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University Course Module Planning for Climate Change Lecture 1 The science of climate change LECTURE 1 THE SCIENCE OF CLIMATE CHANGE Table of Contents I. Overview, learning objectives and notes to instructors ............................................................ 5 II. Suggested reading assignments .............................................................................................. 6 III. Lecture Notes ......................................................................................................................... 7 A. Introduction to climate change planning .................................................................... 7 1. 2. 3. 4. 5. B. What is climate change? ............................................................................................. 7 The scientific approach to generating climate information...................................... 10 General concepts in climate policy and role of land use planning ........................... 14 Opportunities and challenges for planners ............................................................... 20 Links to other disciplines and planning domains ...................................................... 22 The science of climate change .................................................................................. 23 1. The theory of climate change ................................................................................... 23 a) b) c) d) 2. 3. 4. The climate system: complexity and variability................................................ 23 The greenhouse effect ...................................................................................... 27 The carbon cycle: sources and sinks ................................................................. 34 Thresholds and feedbacks ................................................................................ 37 Evidence of climate change....................................................................................... 39 Probabilities, uncertainties and gaps in our knowledge ........................................... 44 Techniques of climate modeling ............................................................................... 47 a) Construction of general circulation models...................................................... 48 b) Downscaling and regional climate models ....................................................... 53 C. Climate and the built environment ........................................................................... 60 1. 2. Water, air and energy cycles in built environments ................................................. 61 Masking or compounding effects of urban form ...................................................... 65 IV. Exercises and instructional activities ..................................................................................... 66 1. 2. 3. 4. 5. V. Exercise 1 (Introductory video and quiz) .................................................................. 66 Exercise 2 (Dimensions of climate change) ............................................................... 66 Exercise 3 (Extracting climate model data) ............................................................... 66 Exercise 4 (Pros/cons of LUP as a mitigation policy tool) ......................................... 67 Exercise 5 (Identify and discuss key voices on climate change)................................ 67 Suggestions for in-depth exploration..................................................................................... 68 1. 2. 3. 4. 5. In Depth Exploration Topic 1 (Some key climate processes) .................................... 68 In Depth Exploration Topic 2 (More facts about GHGs)............................................ 69 In Depth Exploration Topic 3 (Sources of uncertainty) ............................................. 70 In Depth Exploration Topic 4 (Methods of scenario construction) ........................... 71 In Depth Exploration Topic 5 (Statistical downscaling techniques) .......................... 72 UNIVERSITY COURSE MODULE: PLANNING FOR CLIMATE CHANGE I-2 LECTURE 1 THE SCIENCE OF CLIMATE CHANGE VI. REFERENCES ......................................................................................................................... 73 VII. END NOTES........................................................................................................................... 76 List of figures Figure 1 Representation of the three dimensions of climate change .................................................... 8 Figure 2 Global Climate Model Output – Map of Change In Winter Temperature Projected For Nunavut From 2035-2065. ............................................................................................... 10 Figure 3 Global CO2 emissions related to energy and industry from 1900 to 1990 and for the forty SRES scenarios from 1990 to 2100 shown as an index (1990-1).. ................................. 11 Figure 4 Steps to generate future climate information. ....................................................................... 12 Figure 5 Mitigation and adaptation responses to climate change impacts. ........................................ 14 Figure 6 Depiction of one way in which mitigation and adaptation are linked.................................... 15 Figure 7 Land use practices to mitigate climate change and adapt to it. ............................................. 16 Figure 8 Reduction of industrial emissions through ‘market based’ regulations a key focus of mitigation policy advocates and governments. ...................................................................... 17 Figure 9 Development of alternative energy sources a key element of mitigation agenda. ................. 17 Figure 10 Coastal sensitivity anlysis of Atlantic Canada. ........................................................................ 19 Figure 11 Estimate of the Earth’s annual global mean energy balance. ................................................ 23 Figure 12 Changes in the climate system and external factors can lead to warming or cooling. .......... 24 Figure 13 Greenhouse Effect ................................................................................................................. 27 Figure 14 Atmospheric concentrations of three key GHGs during the last 2000 years. ........................ 28 Figure 15 Increase in observed global average temperature. ................................................................ 28 UNIVERSITY COURSE MODULE: PLANNING FOR CLIMATE CHANGE I-3 LECTURE 1 THE SCIENCE OF CLIMATE CHANGE List of figures (continued) Figure 16 Extent of various forms of radiative forcing since 1750 ......................................................... 29 Figure 17 Depiction of the global carbon cycle and capacity of various sources and sinks. .................. 35 Figure 18 Observed changes in global average surface temperature, average sea level and Northern Hemisphere snow cover relative to period 1961–1990. ........................................ 39 Figure 19 Selected regional climate change observations. .................................................................... 40 Figure 20 Recent and dramatic decrease in Arctic sea ice between 2006 and 2007. ............................ 42 Figure 21 Recent human perturbation of atmospheric CO2 concentrations. .......................................... 43 Figure 22 Probabilities, uncertainty in climate change projections ....................................................... 45 Figure 23 Representation of global grid used in generating general circulation climate models. ......... 48 Figure 24 Depiction of data sources for a general circulation climate model........................................ 49 Figure 25 Spatial detail of the early GCM map, regional models and observations data ...................... 50 Figure 26 Comparison of GCM and RCM spatial resolutions. Source Hadley center. ............................ 53 Figure 27 Scatter plot of precipitation and temperature change models for the 2050s (compared to 1961-1990) for Eastern Ontario. ...................................................................... 55 Figure 28 Scenario map of July precipitation for 2011 to 2040 (compared to 1961-1990).. ................. 56 Figure 29 Bioclimate profile for Regina, SK, projecting mean, maximum and minimum temperatures for 2041-2070 .................................................................................................. 57 Figure 30 Depiction of progress in modeling since the 1970s. ............................................................... 58 Figure 31 Depiction of urban heat island above dense urban areas ...................................................... 62 Figure 32 Motion-based phenomena influencing urban microclimates. ............................................... 62 Figure 33 The meteorologically utopian city (after Landsberg 1973). ................................................... 64 UNIVERSITY COURSE MODULE: PLANNING FOR CLIMATE CHANGE I-4 LECTURE 1 THE SCIENCE OF CLIMATE CHANGE Lecture 1 The science of climate change I. Overview, learning objectives and notes to instructors The first part of this introductory Lecture provides a basic description of climate change as a physical phenomenon, identifies some of the key challenges it presents for planners and describes some of the links between climate change planning concepts and those of other academic fields and domains of planning. This helps to situate the course within the profession and the rest of the planning curriculum. The lecture then proceeds with a discussion of key theories and methods in climate change science most relevant to planning. The key learning objectives in that regard include: - - Imparting a basic level of scientific literacy to planning students, including understanding of the basic scientific theories and lines of evidence of climate change; Describing the nature and extent of probabilities and uncertainty regarding climate theories and projections; Setting out some of the basic methods of climate modeling and key sources of climate information for Canadian planners; Explaining how the urban environment impacts, and is impacted by, climatic conditions and can therefore mask or exacerbate climate change in cities. The lecture is divided into three parts: Section A Introduction to climate change planning Section B The science of climate change Section C Climate and the built environment It is expected that Section B, on the science of climate change, will require the greater part of the time allotted to this Lecture. This Lecture relies on a series of images to illustrate the science and evidence of climate change and therefore a projector could be very useful. UNIVERSITY COURSE MODULE: PLANNING FOR CLIMATE CHANGE I-5 LECTURE 1 THE SCIENCE OF CLIMATE CHANGE II. Suggested reading assignments On land use planning and climate change generally: - Chapter 1 of Davoudi, S., J. Crawford, et al. (2009). Planning for climate change: strategies for mitigation and adaptation for spatial planners. London ; Sterling, VA, Earthscan - Campbell, H. (2006). "Is the Issue of climate change too big for spatial planning?" Planning Theory & Practice 7(2): 201 – 230 On the basic science of climate change: - IPCC, 2007: Summary for Policymakers. In: Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change [Solomon, S., D. Qin, M. Manning, Z. Chen, M. Marquis, K.B. Averyt, M.Tignor and H.L. Miller (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA (available on line at http://www.ipcc.ch/pdf/assessment-report/ar4/wg1/ar4-wg1-spm.pdf - PewCenter (2009, 19 July 2010). "Key scientific developments since the IPCC Fourth Assessment Report." from http://www.pewclimate.org/docUploads/Key-ScientificDevelopments-Since-IPCC-4th-Assessment.pdf - McKeown, A. and G. Gardner (2009). Climate change reference guide. Washington, DC, Worldwatch Institute (available at www.worldwatch.org/files/pdf/CCRG.pdf) - ENSEMBLES (2009). "Understanding Climate Science." Retrieved 16 July 2010, from http://www.cru.uea.ac.uk/projects/ensembles/pus/index.html - PewCenter (2009). Climate Change 101: Understanding and responding to global climate change. Arlington, VA, Pew Center on Global Climate Change available at http://www.pewclimate.org/docUploads/Climate101-Science-Jan09.pdf On urban climatology: - Arnfield, A. J. (2003). "Two decades of urban climate research: a review of turbulence, exchanges of energy and water, and the urban heat island." International Journal of Climatology 23: 1 - Souch, C. and S. Grimmond (2006). "Applied climatology: urban climate." Progress in Physical Geography 30(2): 270-279 UNIVERSITY COURSE MODULE: PLANNING FOR CLIMATE CHANGE I-6 LECTURE 1 THE SCIENCE OF CLIMATE CHANGE III. Lecture Notes A. Introduction to climate change planning Climate change is first and foremost a physical phenomenon, describing systems, conditions and interactions present and occurring in the physical world. In recent decades, climate change has been the subject of an intense inter-disciplinary scientific research efforts focused on understanding how climate change occurs and projecting possible climates of the future. Planning for climate change therefore requires learning the theories, methods and findings of climate change science. 1. What is climate change? When scientists speak of climate change, they are referring simply to the warming of the Earth’s surface, including the oceans and the atmosphere, and to the many consequences flowing from that global warmingi. A warming trend has been observed in recent decades and is reflected in a rise in the global average of air temperatures (Solomon, Qin et al. 2007). Scientists believe most of the recent increase in global temperature is very likely caused by human activity, primarily the burning of fossil fuels and, to a lesser extent, agriculture, deforestation and other human practices that alter the land (IPCC 2007). These activities contribute to a rise in the concentration of certain gases, known as ‘greenhouse gases’ (GHGs), which trap heat in the atmosphere. Global warming is expected to affect the climate in four waysii: - Changes to the weather ‘normals’ or mean conditions; - Greater variance in the range of typical conditions (less predictable, more erratic weather); - More frequent, more severe or longer extreme events; and - Changes in the composition and temperature of oceans, causing sea levels to rise. 2. Figure 1 below may be used to illustrate three ways in which a temperature) may change as a result of climate change. Exercise 1 (Introductory video and quiz) The following video by National Geographic is helpful for setting the stage. Global Warming 101 http://video.nationalgeographic.com/video/player/environment/global-warmingenvironment/global-warming-101.html (3 minutes). Can be used with accompanying on-line Global Warming Quiz of about 10 min: http://environment.nationalgeographic.com/environment/global-warming/quiz-global-warming/. Exercise 2 (found at page 66 of this Lecture) asks students to provide examples of different types of climate outcomes of global warming for a particular region, learning to distinguish changes in climate mean, variances and extremes. From those potential climate outcomes, there flow a multitude of secondary effects or impacts, touching virtually every life form on the planet and all human endeavours. That is because both human UNIVERSITY COURSE MODULE: PLANNING FOR CLIMATE CHANGE I-7 LECTURE 1 THE SCIENCE OF CLIMATE CHANGE societies and ecosystems are deeply and intricately connected to each other and to the climate system. A change in the climate can have broad, deep and lasting effects, both positive and negative. UNIVERSITY COURSE MODULE: PLANNING FOR CLIMATE CHANGE I-8 LECTURE 1 THE SCIENCE OF CLIMATE CHANGE Figure 1 Representation of the three dimensions of climate change (i.e., change in normal values, variances and extremes), in the case of air temperatures (http://tinyurl.com/32f8e3b). UNIVERSITY COURSE MODULE: PLANNING FOR CLIMATE CHANGE I-9 LECTURE 1 THE SCIENCE OF CLIMATE CHANGE It is important for students to be clear about the difference between climate and weather. As NASA explains: The difference between weather and climate is a measure of time. Weather is what conditions of the atmosphere are over a short period of time, and climate is how the atmosphere behaves over relatively long periods of time. In most places, weather can change from minuteto-minute, hour-to-hour, day-to-day, and season-to-season. Climate, however, is the average of weather over time and space. An easy way to remember the difference is that climate is what you expect, like a very hot summer, and weather is what you get, like a hot day with popup thunderstorms. NASA, "Climate and Global Change, Features: What is the Difference Between Weather and Climate?", available at http://tinyurl.com/2fqcug. The distinction is critical and helps explain how it is possible to project the climate (a longer term set of conditions) with confidence while the weather (a short term highly variable event) can not be predicted with confidence more than a few days in advance. Key teaching points CLIMATE CHANGE = GLOBAL WARMING CLIMATE OUTCOMES (temps, rains, winds, sea level) IMPACTS (env, social, econ, etc…) DIMENSIONS OF CHANGE = MEANS | VARIANCE | EXTREMES DISTINCTION BETWEEK CLIMATE AND WEATHER: A MEASURE OF TIME Learn more - Frequently Asked Questions from IPCC’s 2007 4th Assessment Report, available at http://www.ipcc.ch/pdf/assessment-report/ar4/wg1/ar4-wg1-faqs.pdf. - Synthesis Report from IPCC’s 2007 4th Asessment http://www.ipcc.ch/pdf/assessment-report/ar4/syr/ar4_syr.pdf. Report, available at UNIVERSITY COURSE MODULE: PLANNING FOR CLIMATE CHANGE I-10 LECTURE 1 THE SCIENCE OF CLIMATE CHANGE 3. The scientific approach to generating climate information Scientists use a variety of analytical tools to project climate change far into the future, identify potential impacts to ecosystems and communities, and describe how they may respond. There are three basic steps in the process of generating scientific information about climate change: - GHG emissions scenarios and other assumptions about factors affecting climate are constructed; - Based on those scenarios, climate models are run to project climate change for a given climate variable, geographic area and time period; - Assessments of impacts, vulnerabilities, and adaptive capacity of communities or ecosystems are completed. Climate models are often cited by policy advocates and constitute a primary resource for planners. They are essentially very complex computer programs that mimic the behaviour of various components of the climate system. Figure 2 shows output data from a global model created by scientists at the University of Victoria. With this run of their model, they projected winter time temperature change for the period from 2035 to 2065. According to the model, areas of Nunavut would warm by as much as 6.9°C. A more detailed description of the techniques of climate modeling is provided in Section B(5) of this Lecture. Figure 2 Global Climate Model Output – Map of Change In Winter Temperature Projected For Nunavut From 2035-2065 (PCIC 2010). UNIVERSITY COURSE MODULE: PLANNING FOR CLIMATE CHANGE I-11 LECTURE 1 THE SCIENCE OF CLIMATE CHANGE Exercise 3 (found at page 66 below) requires students to access this modeling database and produce climate change projections for a particular climate variable, region and time frame. An important assumption of any climate change model is the extent of GHGs in the atmosphere at any one time. Recall that human-induced increases in GHGs are believed to be causing most of the global warming observed to date. Accordingly, a specific pathway of future GHG concentrations must be constructed. These are known as emission scenarios. A commonly used set of such scenarios, describing alternative socio-economic and development futures for the planet were described by the Intergovernmental Panel on Climate Change (IPCC) in a Special Report on Emissions Scenarios (SRES) (Nakicenovic, Alcamo et al. 2000). See Figure 3. Figure 3 Global CO2 emissions related to energy and industry from 1900 to 1990 and for the forty SRES scenarios from 1990 to 2100 shown as an index (1990-1). The dashed time-paths depict individual SRES scenarios and the area shaded in blue the range of scenarios from the literature as documented in the SRES database. 4. Clouds: In Depth Exploration Topic 1 (Some key climate processes) On a cloudy day, less radiation from the sun reaches the Earth's surface and we feel cool. On the other hand, on a cloudy night the heat generated during the day is trapped and the temperature near the surface remains relatively warm. Thin cirrus clouds high up in the atmosphere let solar radiation in and trap exiting terrestrial radiation, warming the climate. Low level, thicker clouds reflect sunlight and trap little infra-red radiation. Their dominant effect is believed to be cooling the surface climate. UNIVERSITY COURSE MODULE: PLANNING FOR CLIMATE CHANGE I-12 LECTURE 1 THE SCIENCE OF CLIMATE CHANGE The oceans: They take much longer to warm up than the land. They also move heat around the globe; for example, the Gulf Stream in the north Atlantic Ocean brings warm water from the tropical Atlantic up to northern Europe, and has a strong effect on the temperatures that the UK experiences. The land surface: It influences how much radiation is absorbed at the surface. An area that is covered in trees will be dark and will heat up more by absorbing more radiation. Areas covered in ice, or at the opposite extreme desert, will both reflect more radiation and absorb less heat. Aerosols: These are atmospheric particles, such as sulphate and black carbon, that are produced naturally from volcanoes and forest fires, as well as by humans from fossil fuel power stations and other industrial activities. They generally have a cooling effect on climate, by reducing the amount of sunlight reaching the surface and by changing the properties of clouds. The presence of man-made aerosols is reducing global warming in the short term. The biosphere: Plants, soils and algae absorb half of the carbon dioxide that man produces. The latest climate model predictions suggest that this will not continue indefinitely and that some parts of the biosphere (in particular soils) could start to release carbon if temperatures increase too much. Source: http://news.bbc.co.uk/2/hi/science/nature/6320515.stm UNIVERSITY COURSE MODULE: PLANNING FOR CLIMATE CHANGE I-13 LECTURE 1 THE SCIENCE OF CLIMATE CHANGE In Depth Exploration Topic 2 (More facts about is one area suggested for more in-depth study (at page 68 below). The construction of scenarios and climate models are only the first steps in the generation of climate change knowledge. Next, the impacts on ecosystems and communities of the projected change must be determined. The nature and severity of an impact depends in part on the vulnerability (susceptibility) of the natural or human system involved, the extent and frequency of exposure and the capacity of the system to withstand or absorb a change (i.e., adapt). Various techniques and methods have been devised to perform such studies. They are referred to in the literature as impacts, adaptation and vulnerability assessments. Significantly, both scientific and other forms of knowledge, including community and traditional experience and histories, may be highly relevant in such assessments. Figure 4 below summarizes in graphic form the three basic steps in generating climate change knowledge. Figure 4 Steps to generate future climate information. Source: (Kropp and Scholze 2009) UNIVERSITY COURSE MODULE: PLANNING FOR CLIMATE CHANGE I-14 LECTURE 1 THE SCIENCE OF CLIMATE CHANGE A more detail description of how climate models and scenarios are constructed is set forth later in this Lecture. Lecture 3 is devoted to methods of assessing impacts, adaptation capacity and vulnerabilities. Key teaching points STEPS TO GENERATE SCIENTIFIC CLIMATE KNOWLEDGE: Select emission scenarios and other assumptions Construct and run climate model Assess impacts, adaption and vulnerability MULTIPLE SOURCES OFRELEVAN T INFORMATION TO BE INTEGRATED Learn more - Kropp, J. and M. Scholze (2009). Climate Change Information for Effective Adaptation. Eschborn, Germany, available at http://www2.gtz.de/dokumente/bib/gtz2009-0175en-climate-changeinformation.pdf UNIVERSITY COURSE MODULE: PLANNING FOR CLIMATE CHANGE I-15 LECTURE 1 THE SCIENCE OF CLIMATE CHANGE 5. General concepts in climate policy and role of land use planning The literature on climate change recognizes two basic ways human societies may respond, mitigation and/or adaptation: Mitigation refers to measures to stop human interference with the climate system by either reducing emissions of GHGs or increasing their removal from the atmosphere. GHG concentrations would thus be stabilized at a certain concentration (e.g., 450 parts per million). The ultimate goal of mitigation, as articulated by the United Nations, is to prevent a dangerous level of climate change so as to allow ecosystems to adapt naturally, ensure food production and enable sustainable development (UN 1992); Adaptation, by contrast, comprises those adjustments in natural or human systems intended to moderate harm and exploit opportunities arising from a changing climate (IPCC 2007). The goal of planned adaptation is to make those adjustments in anticipation of a change in conditions, rather than reacting after the change has been experienced. Note the differences in objectives: adaptation is largely focused on responding to the impacts of climate change (“managing the unavoidable”), while mitigation addresses the underlying causes of climate change (“avoiding the unmanageable”) (Kropp and Scholze 2009) (See Figure 5). Figure 5 Mitigation and adaptation responses to climate change impacts. Source: (Smithers and Smit 1997) UNIVERSITY COURSE MODULE: PLANNING FOR CLIMATE CHANGE I-16 LECTURE 1 THE SCIENCE OF CLIMATE CHANGE These two policy responses, mitigation and adaptation, are interrelated in multiple and complex ways. For instance, the more successful mitigation is, the less necessary adaptation may become. See Figure 6. There has been controversy regarding which of the two responses should take precedence. Some argue that pursuing adaptation (especially in richer societies) is wrong in that it arguably diverts resources from efforts to correct the problem, leaving those most at risk (generally poorer societies) to suffer [cite]. Perhaps for that reason, more attention was given to mitigation policy at the initial international negotiations on climate change beginning in the late 1980s. More recently adaptation has become more prominent in international policy dialogues. [cite] Figure 6 Depiction of one way in which mitigation and adaptation are linked. Should mitigation succeed in keeping global temperature rise below 2°C, the extent of adaptation needed is presumed to be lower, especially in the long term (Kropp and Scholze 2009). Land use practices and the spatial planning system have been recognized as key arenas for both mitigation and adaptation policies. However, each of these policy objectives calls for different sets of planning measures and tools. See Figure 7. Further, there is overlap (synergies) between mitigation and adaptation measures as well as potential for conflict. Indeed, their integration into a coherent set of climate policies, and how that may fit within the larger sustainability and development agendas, are areas of considerable scholarly interest (Davoudi, Crawford et al. 2009, 14); (Pizarro 2009); (Swart and Raes 2007). We discuss those issues in detail in Lecture 2. What follows are some key points to serve as an introduction to the subject. UNIVERSITY COURSE MODULE: PLANNING FOR CLIMATE CHANGE I-17 LECTURE 1 THE SCIENCE OF CLIMATE CHANGE Figure 7 Many land use practices have been advocated to mitigate climate change as well as to adapt to it. Many measures are effective for both. Synergies and conflicts in mitigation and adaptation plans are explored in Section E of Lecture 2. In general, land use planning for mitigation of climate change entails pursuing development pathways toward lower GHG emissions, principally through lower fossil fuel use. Development would be focused on improving the energy efficiency of buildings, infrastructures and transportation systems, and promoting lower consumption lifestyles and a strong conservation ethic. Measures might include the protection of trees, zoning for denser, mixed use development to reduce transportation demand and promote transit, green building codes and subsidies for retrofits, permitting of renewable energy generation and distribution systems and the creation of community gardens. Note that many mitigation measures are staples of other planning movements and concepts like New Urbanism, Transit Oriented Development, Smart Growth and Peak Oil, that call for less fuel dependent, healthier urban environments, although for reasons unrelated to climate change. UNIVERSITY COURSE MODULE: PLANNING FOR CLIMATE CHANGE I-18 LECTURE 1 THE SCIENCE OF CLIMATE CHANGE Methods often employed in mitigation planning include the generation of inventories of GHG emissions, long term visioning exercises, public awareness and education campaigns, pilot projects at municipal sites and the promulgation of community energy plans. The land use planning system is only one of many policy instruments that may be used to stabilise GHG concentrations. Indeed it may be said that land use planning has not been a primary focus of mitigation policy to date. GHG reduction policies often target energy policy, industrial and environmental regulations or tax rules. For example, Canada’s policy proposals for mitigation have relied heavily on regulation of emissions from industrial sources (so-called ‘large final emitters’), proposing ‘cap and trade’ schemes to reduce them, in addition to fuel efficiency requirements for new vehicles and incentives for energy improvement of consumer products. (EnvironmentCanada 2008). Two provinces, British Columbia and Quebec, have introduced ‘carbon taxes’, levied on fossil fuel sales or distribution (BCEnvironment 2010). None of those approaches directly involve the land use planning system. There are a number of political and practical reasons why this may be. Existing air emissions legislation provides a ready platform for regulatory action at national and provincial levels. The relatively small number of large final emitters arguably presents political opportunities (and challenges) for immediate action and short term results. Figure 8 Reduction of industrial emissions through ‘market based’ regulations is a key focus of mitigation policy advocates and governments. Image source: http://www.avc2009.org/avc2009/img/emission.jpg Figure 9 Development of alternative energy sources and improvement of electricity distribution systems are key elements of the mitigation agenda, with important implications for land use planning systems. UNIVERSITY COURSE MODULE: PLANNING FOR CLIMATE CHANGE I-19 LECTURE 1 THE SCIENCE OF CLIMATE CHANGE Image source: http://tinyurl.com/2etfdgj And yet, many have argued that land use planning offers important advantages as a mitigation policy tool, especially in the long term. Land use planning targets the underlying physical conditions that drive (some way compel) fuel demand to a large extent (e.g., prevailing transport modes and distances to be travelled, housing size and type). Further, as much mitigation policy is promulgated through international and national-level policies, planning may have an important role to play in effectively ‘localising’ mitigation objectives (Davoudi, Crawford et al. 2009). Exercise 4 (Pros/cons of LUP as a mitigation policy tool) at page 67 asks students to consider the advantages and drawbacks of land use planning as a mitigation policy tool Key teaching points TABLE 1 GOALS AND TYPICAL METHODS AND MEASURES OF MITIGATION AND ADAPTATION POLICY. MITIGATION ADAPTATION Sample LUP measures Goal Common LUP Methods Core policy areas stabilize GHG concentrations GHG inventories, long term visioning, public awareness and education, pilot projects, community energy plans green building codes, density bonuses near transit, protection of urban canopy emission regulations, tax policy, industrial and trade rules minimize loss maximize gain risk, adaptation and vulnerability assessments, public awareness and education flood zone controls, heat alert systems, stronger building codes land use planning, emergency/crisis response, risk management MANY SYNERGIES / POTENTIAL CONFLICTS BETWEEN ADAPTATION AND MITIGATION MEASURES LAND USE PLANNING AS BOTH MITIGATION AND ADAPTATION POLICY TOOL, WITH VARIOUS ADVANTAGES AND DISADVANTAGES RELATIVE TO OTHER POLICY AREAS. Learn more - Chapter 1 of Davoudi, S., J. Crawford, et al. (2009). Planning for climate change: strategies for mitigation and adaptation for spatial planners. London; Sterling, VA, Earthscan - Campbell, H. (2006). "Is the Issue of climate change too big for spatial planning?" Planning Theory & Practice 7(2): 201 – 230 UNIVERSITY COURSE MODULE: PLANNING FOR CLIMATE CHANGE I-20 LECTURE 1 THE SCIENCE OF CLIMATE CHANGE With regard to adaptation, the efforts is clearer and core a call for and management of Measures and infrastructures to communities regarding new risks, are staples of the planner’s agendaiv. See Figure 10. Figure 10 The analysis and amelioration of hazards, such as coastal sensitivity to sea level rise as in this study of Atlantic Canada, is a core function of existing land use planning systems. UNIVERSITY COURSE MODULE: PLANNING FOR CLIMATE CHANGE I-21 LECTURE 1 THE SCIENCE OF CLIMATE CHANGE This course devotes more attention to adaptation rather than to mitigation. As will be discussed in detail later, Canada is vulnerable to a range of impacts associated with climate change, including rising temperatures, more frequent, intense storms and rising sea levels. These changes are already affecting community life in many ways from environmental through long-term economic, health and social implications. Communities need to understand these changes but more importantly, must develop strategies and plans for adaptation and build these strategies into their day-to-day planning and decision-making processes. Planners are one of the key professional groups that have the ability to mainstream climate change adaptation strategies in their communities. The bulk of these Lectures address methods and tools of planning relevant to adaptation, not mitigation. Nonetheless, we do address the methods of mitigation planning in some greater detail in Section C of Lecture 2. UNIVERSITY COURSE MODULE: PLANNING FOR CLIMATE CHANGE I-22 LECTURE 1 THE SCIENCE OF CLIMATE CHANGE 6. Opportunities and challenges for planners Human settlements have been planned with consideration of climatic conditions since time immemorial (Oke 1984). Since its inception, the planning profession has been engaged in the systematic and comprehensive analysis and amelioration of varied social and environmental problems. Indeed, many land use practices believed to reduce GHG emissions are similar to those advocated by planners long before climate change became a hot topic for policy makers. On the adaptation side, many of the most serious impacts from climate change merely heighten risks already present and against which planners have well known responses (Bicknell, Dodman et al. 2009, 4). In light of the above, how is climate change different from other problems planners deal with every day? Couldn’t climate change be planned for using existing land use practices and techniques? There appear to be some distinct (though not necessarily unique) challenges that climate change planners tackle. Many of these stem from the deep uncertainties and strong disagreements which pervade climate change science and policy. Planning for climate change may require new ways of thinking about growth and development and new planning processes and tools (Davoudi et al. 2009). Key practical challenges for climate change planners include: - Applying complex scientific data and other forms of climate knowledge Planning in a highly contested political environments Decision making in conditions of high uncertainty and serious risk Reconciling climate change policy goals and development objectives Developing more effective land use planning tools and methods Ensuring vertical and horizontal coordination in climate planning. We will look at these challenges in the Lectures that follow, particularly Lectures 2 and 4. More fundamentally, climate change raises questions about the role of land use planning as human civilisation faces a grave environmental threat (Bulkely 2006; Byrne et al 2009). Planning occurs within a particular social, economic and political context and is subject to various social influences. It has been called a forum where policy and governing principles are continually negotiated and reinforced (Bulkeley & Betsill). Thus, it not only acts as an instrument for policy implementation but as a forum where social interests are traded off and social practices forged. Planners must give serious consideration to how climate change objectives are framed within development debates and the planning agenda. This suggests a number of fundamental questions: Is the planning system part of the problem? If so, how may it be reformed to improve our chance of survival as a civilisation? Is climate change an environmental or a development problem at its core, or both? Will the climate change crisis require a reframing of ‘sustainable development’ to highlight the environmental/ecological goals embedded therein? Many planning theorists have noted the loss of confidence in large scale planning after the 1960s, in part due to a rejection of urban revitalisation plans. Will climate change give planning, at last, a new ‘big idea’ upon which to base large-scale plans and unit society behind a new comprehensive visionary idea of urban life? (Breheny 1996; Berke 2002) We return to many of these questions in Section A of Lecture 2. UNIVERSITY COURSE MODULE: PLANNING FOR CLIMATE CHANGE I-23 LECTURE 1 THE SCIENCE OF CLIMATE CHANGE Table 2 Land use planning and climate change, areas of concern, development goals and key challenges. key challenges development goals area of concern Mitigation how design and operation of settlements impacts: use of fuel for transport energy use in buildings and infrastructures consumption and generation/management of waste siting of energy generation plants and distribution networks preservation of open areas / trees (carbon sinks) steer development toward low emission/low consumption path Adaptation how design and operation of settlements impacts exposure and vulnerability to climate hazards interaction of built environment with natural water, air and heat cycles and ecosystems capacity of social networks to cope with climate stress identify and prioritize climate risks prepare for (prevent, reduce and spread) climate risks increase community adaptive capacity and resilience generation and use of relevant climate knowledge vertical and horizontal policy coordination ‘localising’ national policy targets capacity building (knowledge of policy, markets, governance and technologies) consensus on risks capacity building (impacts and vulnerability modeling and assessments, scenarios) avoiding mal-adaptations integrating mitigation/adaptation/sustainable development goals MORE….. UNIVERSITY COURSE MODULE: PLANNING FOR CLIMATE CHANGE I-24 LECTURE 1 THE SCIENCE OF CLIMATE CHANGE 7. Links to other disciplines and planning domains Many of the methods, tools and practices used by Canadian planners today are highly useful and readily applicable to climate change planning. In other respects, climate change objectives may frustrate or complicate existing objectives and practices. Planners need to exploit those synergies and address any conflict as climate change concerns begin to be incorporated in the planning agenda. Concepts and skills learned in this course will to some extent reinforce what the students learn in other courses. Table 2 provides an outline of some of the overlap between key concepts and practices of other professions and domains of planning, and the work of a climate change planner. Table 3 Synergies between planning for climate change and other professions, domains of planning. Profession or domain Key concept or practice Transportation planning Improved fuel efficiency, reduced demand in transportation services Environmental planning Earth’s carrying capacity, sustainability principle, ecological footprints and limits/constrains to growth (ecological economics) Engineering Green infrastructure and building design Relevance to CC planning Disaster / risk management Urban climatology Public health Architecture UNIVERSITY COURSE MODULE: PLANNING FOR CLIMATE CHANGE I-25 LECTURE 1 THE SCIENCE OF CLIMATE CHANGE B. The science of climate change 1. The theory of climate change a) The climate system: complexity and variability While we often think and talk about the weather, what is it that produces the temperatures, winds or snow storms that we experience from day to day? The climate is in fact a bio-physical system of enormous complexity involving interactions between the atmosphere, the oceans, the water cycle (i.e., evaporation, condensation and precipitation), ice, snow and frozen ground, the land surface and even living organisms. The atmosphere is the most unstable, rapidly-changing component of that system. It is the flow of energy between the different layers of the atmosphere (especially the lower troposphere and the stratosphere above it) that is believed to drive most of the circulation of air masses and ocean currents that lead to weather and climate patterns (IPCC, 610). Energy enters the climate system from space in the form of radiation from the Sun. Solar (short-wave) radiation, once it arrives on Earth, can be absorbed, scattered or reflected, re-emitted as heat, transferred between the various components of the climate system, absorbed by organisms or re-emitted back to space. See Figure 11. The net balance of energy in the system determines the global temperature. That balance can change in response to the internal dynamics of the system or through the influence of external factors like volcanoes or various forms of pollution. Figure 11 Estimate of the Earth’s annual global mean energy balance. About half of the incoming solar radiation is absorbed by the surface. This energy is transferred to the atmosphere by surface thermals, evapo-transpiration and surface radiation absorbed by clouds and GHGs. The atmosphere in turn radiates energy back to Earth and out to space. Source: IPCC (2007). UNIVERSITY COURSE MODULE: PLANNING FOR CLIMATE CHANGE I-26 LECTURE 1 THE SCIENCE OF CLIMATE CHANGE Scientists refer to those external influences on the net energy balance, including human interferences, as radiative forcing. If such forcing causes more energy to be stored in the system, it will lead to global warming. If the forcing causes more energy to escape, the system will cool. As reported by the IPCC, there are three fundamental ways to change (or ‘force’) the net energy balance of the Earth and thus alter the climate: 1) changing the amount of incoming solar radiation; 2) changing the fraction of solar radiation that is reflected back to space; and 3) trapping the radiation which emanates from Earth (the greenhouse effect). IPPC 20078 (http://www.ipcc.ch/pdf/assessment-report/ar4/wg1/ar4-wg1-faqs.pdf). Changes in solar inputs (item 1) may occur due to changes in the Earth’s orbit around the Sun or in the function of the Sun itself (e.g., Sun spots) (Garnaut 2008, 27). The other two, changes in albedo and the trapping of terrestrial radiation, can occur as a result of changes in the composition and circulation of the atmosphere and oceans, the type and amount of clouds, the hydrologic cycle, the uses of the land, or the extent of ice, snow and frozen ground. See Figure 12. Image source: http://www.ipcc.ch/graphics/ar4-wg1/jpg/faq-1-2-fig1.jpg Figure 12 Changes in the internal dynamics of the climate system and influences from external factors such as volcanoes and human activities can alter the net energy balance of the overall system, leading to global warming or cooling. UNIVERSITY COURSE MODULE: PLANNING FOR CLIMATE CHANGE I-27 LECTURE 1 THE SCIENCE OF CLIMATE CHANGE Radiative forcing of the second type, which involves a change in reflectivity (or albedov) values, could occur as a result of a volcanic eruption that releases tiny reflective particles (aerosols) into the upper reaches of the atmosphere, tending to cool it. An increase in clouds could have a similar cooling effect, as the top of the clouds reflect sunlight back toward space (note that clouds also absorb heat emanating from the surface, producing localised warming) (Garnault 29). A decrease in the extent of vegetation or ice cover can also lower surface reflectivity (dark surfaces absorb more heat) and thus increase global temperatures. It is the third type of radiative forcing, the trapping of the terrestrial radiation, which most concerns climate change scientists. There, it is a change in the composition of the atmosphere itself, due in large part to human activity, which is believed to increase the natural ability of the atmosphere to trap terrestrial radiation. This is the so-called greenhouse effect, discussed in more detail later on. While the greenhouse effect has attracted the most attention, it should be clear that human activity may interfere with the energy balance of the climate system through changes in reflectivity as well (item two on the list above). For instance, our air pollution adds to the presence of aerosols. Aviation and shipping are believed to contribute to cloud formation. Deforestation and other changes in land use affect surface reflectivity as well. In Depth Exploration Topic 1 (Some key climate processes) found at page 68 below describes in further detail how clouds, the oceans, the biosphere and other key components of the climate system influence the extent of radiative forcings. Key teaching points THE CLIMATE SYSTEM IS A BIO-PHYSICAL SYSTEM (IDENTIFY COMPONENTS AND KEY INTERACTIONS) FLOW OF ENERGY, ESPECIALLY BETWEEN LAYERS OF ATMOSPHERE, IS KEY DRIVER OF WEATHER SYSTEMS NET ENERGY BALANCE OF SYSTEM SETS GLOBAL TEMPERATURE AND WARMING OR COOLING TRENDS THREE FORMS OF RADIATIVE FORCING: SOLAR INPUT SURFACE REFLECTIVITY HEAT TRAPPING (GREENHOUSE EFFECT) HUMAN INTEFERENCE, THROUGH VARIOUS MEANS, AFFECTS REFLECTIVITY AND GREENHOUSE EFFECT EXTENT AND SCALE OF NATURAL VARIABILITY HAS IMPLICATIONS FOR SCIENCE AND POLICY MAKING UNIVERSITY COURSE MODULE: PLANNING FOR CLIMATE CHANGE I-28 LECTURE 1 THE SCIENCE OF CLIMATE CHANGE One of the signature characteristics of the climate system is its natural variability. We know that climates vary considerably from one location to another on the planet and from season to season. There are also natural climate cycles that span across several years, such as the El Niño Southern Oscillation (ENSO) and the Pacific Decadal Oscillation (PDO), both of which are regional ocean temperature anomalies. Longer term variations such as glacial and interglacial periods occur in cycles believed to last tens of thousands of years, associated with changes in the orbit of the Earth. This natural variation in the climate has several important consequences for scientists and policy makers. First, human induced climate change may be masked or compounded by natural cycles. Thus, a natural cooling cycle may counter to some extent warming caused by human activity. Some may misinterpret a plateau or slow down in the global temperature rise as evidence that climate change is not caused by humans or that it has stopped. The natural variation in the climate also provides a ‘natural experiment’ for impact and vulnerability assessments (Stehr and Von Storch 1995). For instance, even the most extreme projections of changes in temperature and precipitation at any one location by the end of this century pale in comparison to the differences in the climate of Recife, Brazil and Nunavut, Canada today. Those cities and countless other human settlements have adapted, more or less successfully, to a very wide variety of climates. For scientists, high natural variability makes it harder to identify long term trends in the system and to establish whether observed or projected changes result from human activities (Garnaut 40). UNIVERSITY COURSE MODULE: PLANNING FOR CLIMATE CHANGE I-29 LECTURE 1 THE SCIENCE OF CLIMATE CHANGE b) The greenhouse effect Let’s look more closely at radiative forcing caused by heat trapping in the atmosphere, the so-called ‘greenhouse effect’. Recall it is the accumulation of GHGs due to human activity that scientists believe is very likely the primary source of the recent global warming. Scientists estimate that half of the incoming solar radiation reaches the surface of the Earth (the rest is reflected by the atmosphere and clouds). Recall Figure 11. Some of that energy is then re-emitted by the Earth as longwave, infrared radiation. GHGs present in the atmosphere trap most of this terrestrial radiation, scattering it within the atmosphere and further warming it. This is the greenhouse effect; the gases act to provide additional warmth, much as the glass roof of a greenhouse. See Figure 13. Eighteen GHGs have been identified, many of which occur naturally. The most common is water vapour(H2O), followed by carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), the family of halocarbons (many of them the products of industry) and ozone (O3). Altogether, GHGs account for only a very small fraction of the atmosphere. Water vapour, by far the most common, accounts for only about two percent of the atmosphere by volume. GHG molecules and clouds trap most of the outbound terrestrial infrared radiation (the red arrows), scattering it and further warming the atmosphere. Figure 13 Greenhouse Effect Source: IPCC 2007. "Climate Change 2007. Assessment Report 4, Working Group 1, Historical Overview of Climate Change Science", FAQ 1.3, Figure 1.1. Figures are available at http://www.ipcc.ch/graphics/gr-ar4-wg1.htm UNIVERSITY COURSE MODULE: PLANNING FOR CLIMATE CHANGE I-30 LECTURE 1 THE SCIENCE OF CLIMATE CHANGE It is important to note that the greenhouse effect is a natural occurrence and that is it indeed necessary to keep the Earth warm enough for humans and present ecosystems to survive. Thanks to the greenhouse effect, the average global temperature at the surface is 14°C, or about 33°C warmer than if there were no greenhouse gases at all (Garnaut, 25). The problem lies in the fact that, since the start of the industrial revolution (roughly the year 1750), GHG concentrations have increased significantly. See Figure 14. Carbon dioxide, the second most prevalent GHG (after water vapour) has increased by about 25% since pre-industrial era levels, from about 280 parts per million (ppm) in 1750 to 383 in 2007, increasing in the past ten years at an average rate of two ppm per year. This increase in GHGs has coincided with an observed rise in global average temperatures of a magnitude and rate unprecedented in human history. See Figure 15. Figure 14 Atmospheric concentrations of three key GHGs during the last 2000 years. Source: IPCC (2007). Figure 15 Increase in observed global average temperature. Source: IPCC 2007. UNIVERSITY COURSE MODULE: PLANNING FOR CLIMATE CHANGE I-31 LECTURE 1 THE SCIENCE OF CLIMATE CHANGE Some have asked whether the observed global warming may have been caused by factors other than GHGs or human activity. According to the IPCC, the scientists who have looked at this question estimate that, of all the factors contributing to recent global warming (through different forms of radiative forcing), human activity, and primarily that activity which increases GHGs, is by far the most influential. Figure 16 depicts the relative weight of the various human and natural processes which have contributed to the forcing of the climate. A relatively small increase in solar radiance is the only natural process that has materially influenced the net energy balance of the climate from 1750 to 2005. By contrast the cumulative effect of human activities (some cooling through aerosols and changes in land uses, but mostly warming through GHG emissions) has been many times more influential. Image source Figure 16 This IPCC graph shows the extent of various forms of radiative forcing since 1750, human and natural. Human activity has impacted the concentration of GHGs, ozone and water vapour in the upper atmosphere as well as the reflectivity of the land, the extent of aerosols and linear contrails (from aviation). Of all forms of radiative forcing, GHGs have had the greatest impact. The net effect from all human activities is one of warming (bottom row of graph). The only natural warming of significance between 1750 and 2005 occurred in solar irradiance. Note the considerable uncertainty for some forms of forcing, as represented by the lines extruding beyond each coloured bar. UNIVERSITY COURSE MODULE: PLANNING FOR CLIMATE CHANGE I-32 LECTURE 1 THE SCIENCE OF CLIMATE CHANGE Others have noted that natural concentrations of GHGs have fluctuated significantly over time and that at certain periods in the very distant past have been much, much higher than today. For instance, scientists believe that CO2 exceeded 4000 ppm at some points in the past 400 million years. Yet, there is reason to be concerned about the current rise in GHGs and global temperatures. As Garnaut explains: Apart from the earliest identified hominids, the history of our species [about 200,000 years in length] has been within the period of relatively low carbon dioxide concentrations. … The period in which human civilization has developed, located within an interglacial period known as the Holocene, has been one of equable and reasonably stable temperatures. Concentrations of carbon dioxide now exceed the natural range of the last two million years by 25 per cent, of methane by 120 per cent and of nitrous oxide by 9 per cent (IPCC 2007a: 447). The … rise in carbon dioxide since the beginning of the industrial revolution (around 100 ppm) is about double the normal ‘operating range’ of carbon dioxide during glacial–interglacial cycling (180–280 ppm) (Steffen et al. 2004). … it is not just the magnitude of the post-industrial increase in greenhouse gas concentrations that is unusual, but also the rate at which it has occurred. Garnaut, 25. UNIVERSITY COURSE MODULE: PLANNING FOR CLIMATE CHANGE I-33 LECTURE 1 THE SCIENCE OF CLIMATE CHANGE Besides their ability to trap and scatter terrestrial radiation, GHGs have other characteristics of interest. The intrinsic ability of a particular GHG to trap heat varies greatly. On a molecule for molecule basis, methane is 22 times more potent that CO2. Accordingly, while methane is much less prevalent than CO2, its radiative forcing impact is significant. The most potent GHG of all, sulfur hexaflouride is 22,800 times more powerful as a GHG than CO2. Fortunately, it is very rare. GHGs also differ significantly from one another in how long they remain in the air. Carbon dioxide is particularly stable and long lasting. Over the course of a century, half of the carbon dioxide emitted in any one year will be removed, but around 20% will remain in the atmosphere for millennia. Water vapour is the most abundant GHG. Its impact on temperature is complex. By forming clouds, which reflect solar radiation, it contributes to cooling. Moreover, human activities have only a small direct influence on the amount of atmospheric water vapour. Indirectly, humans have the potential to affect water vapour by changing climate. That is because a warmer atmosphere is able to carry more water vapour. Human activities also influence water vapour through methane emissions as methane undergoes chemical destruction in the stratosphere, producing a small amount of water vapour. In order to simplify discussions, scientists and policymakers often group GHGs, with relative weights assigned based on their heat trapping potential, and refer to “CO2 equivalents”. The term refers to concentrations or emissions of all greenhouse gases that would have an equivalent effect of a stated amount of CO2. For instance, when scientists talk about the impacts of a doubling of CO2, they really mean an increase in greenhouse gases that would produce an effect equivalent to the doubling the CO2 in the atmosphere. In Depth Exploration Topic 2 (More facts about GHGs) found at page 69 provides further information about the characteristics of GHGs. The natural and human sources of various GHGs are identified in Table 4 below. UNIVERSITY COURSE MODULE: PLANNING FOR CLIMATE CHANGE I-34 LECTURE 1 THE SCIENCE OF CLIMATE CHANGE One very important question for scientists is the extent of climate sensitivity of the Earth. The concept of climate sensitivity, as defined by scientists, refers to the extent of global temperature change for a given rise in the concentration of GHGs. It is also conceived as measurement, conventionally defined as the quantity of global average surface warming (in degrees Celsius) that would be experienced as a result of a doubling of carbon dioxide (Garnaut 38). This relationship of GHGs to global warming is critical for climate change scientists and policy advocates alike. It allows us to translate a given climate policy goal (e.g., no more than a 2°C increase in global temperature) into a corresponding GHG concentration (e.g., 450 parts per million CO2 equivalents). A particular GHG concentration can thus be tied to a global temperature change above which advocates believe ‘dangerous’ impacts are likely or inevitable. This can then be used to design specific emission control measures to reach stabilisation at or below that level of GHGs. Climate model data suggests a wide range of climate sensitivity values, depending on assumptions about feedback effects within the climate system. In its Fourth Assessment Report, the IPCC found that it is likely (i.e., greater than a 66% chance) that a doubling of carbon dioxide will lead to a long term temperature increase of between 1.5 to 4.5°C, with a best estimate of about 3°C, and less than 1.5°C very unlikely. Key teaching points GREENHOUSE EFFECT = TRAPPING OF OUTBOUND TERRESTRIAL RADIATION (HEAT) IN ATMOSPHERE HUMAN ACTIVITY PRIMARY INFLUENCE ON RADIATIVE FORCING SINCE 1750 GHG CONCENTRATIONS HISTORICALLY HIGH AND OF CONCERN DESPITE HIGHER PREHISTORIC RECORD KEY GHGS - H2O (MOST PREVALENT, COMPLEX RESPONSE TO HUMAN ACTIVITY, COOLING AND WARMING) CO2 (GREATEST WARMING IMPACT, STANDARD FOR MEASUREMENT) CH4 (POTENT BUT RARER) HALOCARBONS (POTENT, MAN MADE) SOURCES, POTENCY AND LIFETIME OF SPECIFIC GHGS (CONSIDERABLE VARIATION) CLIMATE SENSITIVITY A CRITICAL ISSUE = EXTENT OF WARMING FROM DOUBLING OF CO2 (IPCC: “2°C TO 4.5°C LIKELY “) KEY TO ESTABLISHING POLICY UNIVERSITY COURSE MODULE: PLANNING FOR CLIMATE CHANGE I-35 LECTURE 1 THE SCIENCE OF CLIMATE CHANGE Table 4 Natural and anthropogenic sources of GHGs (Garnaut 2008, 31-32). UNIVERSITY COURSE MODULE: PLANNING FOR CLIMATE CHANGE I-36 LECTURE 1 THE SCIENCE OF CLIMATE CHANGE c) The carbon cycle: sources and sinks Human contributions of carbon dioxide and other GHGs to the atmosphere must be understood in the context of the global, largely natural carbon cycle. This is the process whereby carbon molecules in the atmosphere are removed and converted into organic matter by plants and algae (through the process of photosynthesis) or taken up by the Earth’s oceans and crusts. Scientists refer to carbon sinks to denote those materials and processes which remove carbon. They include sedimentary rocks and marine sediments, the atmosphere, ocean water, fossil fuels, living plans and organic matter in the soil. See Figure 17. There are also multiple carbon sources, those materials and processes that emit GHGs. They include soils and decomposing organic matter, oceans and marine life, among others. See Table 4. Note that the human contribution to the carbon cycle is relatively small but potentially important in terms of climate sensitivity. UNIVERSITY COURSE MODULE: PLANNING FOR CLIMATE CHANGE I-37 LECTURE 1 INTRODUCTION TO CLIMATE CHANGE PLANNING AND THE SCIENCE OF CLIMATE CHANGE Image source Figure 17 Depiction of the global carbon cycle and capacity of various sources and sinks. Red figures indicate extent of human interference. UNIVERSITY COURSE MODULE: PLANNING FOR CLIMATE CHANGE I-38 LECTURE 1 THE SCIENCE OF CLIMATE CHANGE In light of the natural carbon cycle, projecting the accumulation of GHGs is a function of two variables: (1) the rate of emissions (human and natural) and (2) the rate of natural removal (oceans and vegetation primarily). For policy makers and planners, there are a number of salient points in this regard: - Stabilizing GHG concentrations or reducing them will be made difficult by the long life of some GHG molecules and the fact that current emission rates for CO2 may be much higher than the natural absorption rate. Avoiding ‘dangerous’ human interference with the climate may thus require dramatic, long term reduction in human carbon emissions. Some argue that in fact it is necessary to ‘overshoot’ a GHG reduction objective, that is produce even less than the natural absorption rate, and do so soon if we are to avoid the worst effects of climate change (Garnaut 46); - Reducing GHG concentrations will not result in an immediate slow down or stop of climate change. The internal dynamics of the climate system are such that it may not reach a new equilibrium temperature for a very long time. In this regard, scientists point to the role of the oceans, capable of storing enormous amounts of heat and to hold it for decades or even centuries. Additional heat stored there will continue to alter the net energy balance of the climate system long after GHGs return to pre-industrial levels; - Two policy options exist to achieve stabilization. One may reduce emissions through the sort of measures described above (reduction of fuel use, increased efficiency, etc.) Alternatively, one may accelerate the removal of GHG, increasing the capacity of carbon sinks. Aforestation (planting more trees) is the measure that comes readily to mind. Other, more esoteric (and potentially risky) geo-engineering proposals have been advanced. For example, some wish to seed the oceans with iron compounds to increase CO2 absorption. Some other measures focus instead on cooling through increased reflectivity, proposing that airplanes disperse aerosol particles in the upper reaches of the troposphere or ships that spray sea water into the air to increase cloud formation. UNIVERSITY COURSE MODULE: PLANNING FOR CLIMATE CHANGE I-39 LECTURE 1 THE SCIENCE OF CLIMATE CHANGE d) Thresholds and feedbacks Predicting precisely how the climate system will respond to a certain amount of forcing is made much more difficult by the non-linearity of some relationships/interactions within the climate system and the external bio-physical environment. There are many feedback mechanisms that can either amplify (‘positive feedback’) or diminish (‘negative feedback’) the effects of a change. For instance: as rising concentrations of GHGs warm the planet, snow and ice begin to melt. This melting reveals darker land and water surfaces that were beneath the snow and ice, and these darker surfaces absorb more of the Sun’s heat, causing more warming, which causes more melting, and so on, in a self-reinforcing cycle. This feedback loop, known as the ‘ice-albedo feedback’, amplifies the initial warming caused by rising levels of greenhouse gases. IPCC 2007 (http://www.ipcc.ch/pdf/assessment-report/ar4/wg1/ar4-wg1-faqs.pdf) There are also feedbacks in the interaction between the carbon cycle and the climate system. They occur when changes in climate affect the rate of absorption or release of carbon dioxide from land and oceans. Examples of climate–carbon feedbacks include the decrease in the ability of the oceans to remove carbon dioxide from the atmosphere with increasing water temperature, reduced circulation and increased acidity (IPCC 2007a: 531); and the weakening of the uptake of carbon in terrestrial sinks due to vegetation dieback and reduced growth from reduced water availability, increased soil respiration at higher temperatures and increased fire occurrence. Methane release from melting permafrost can also constitute a feedback loop. (Kropp and Scholze 2009). Garnaut (2008, 37) describes the problems presented by thresholds as follows: Many of the processes within the climate and other earth systems (such as the carbon cycle) are well buffered and appear to be unresponsive to changes until a threshold is crossed. Once the threshold has been crossed, the response can be sudden and severe and lead to a change of state or equilibrium in the system. This is often referred to as rapid or abrupt climate change...a small change can have large, long-term consequences. The threshold at which a system is pushed into irreversible or abrupt climate change occurs is often referred to as the ‘tipping point’. In other cases, the crossing of a threshold may lead to a gradual response that is difficult or even impossible to reverse. An example is the melting of the Greenland ice sheet, which may occur over a period of hundreds of years, but once started, would be difficult to reverse. For most elements of the climate system there is considerable uncertainty as to when the tipping point might occur, but with each increment of temperature rise, the likelihood of such an event or outcome increases. UNIVERSITY COURSE MODULE: PLANNING FOR CLIMATE CHANGE I-40 LECTURE 1 THE SCIENCE OF CLIMATE CHANGE For planners and policy makers, the implications are significant. The pathway of climate change may not be smooth, predictable or amenable to reversal. Once certain conditions are reached, the system may proceed in an unexpected, inexorable way towards a new equilibrium point, frustrating human attempts to shape or alter the rate or direction of further change. Refer to Table 5 for a list of select tipping points and possible climate consequences. Table 5 Tipping points that may destabilise the climate system through positive feedbacks and consequences expected. Source: (McKeown and Gardner 2009) UNIVERSITY COURSE MODULE: PLANNING FOR CLIMATE CHANGE I-41 LECTURE 1 THE SCIENCE OF CLIMATE CHANGE 2. Evidence of climate change As with any scientific theory, climate change is based not only on laboratory experiments and mathematical analyses, but also on observations and measurements in the natural world. This section examines the observed evidence that global warming and climate change are in fact occurring. There is high confidence that the Earth’s atmosphere is warming based on global and regional observations. Eleven of the 12 warmest years on record (since 1850) have occurred between 1995 and 2006. The global average surface temperature has increased by 0.74°C over the past 100 years (Field et al. 2007). See Figure 18. Increases in sea level and decreases in snow and ice cover have also been observed, consistent with warming. Based on those and other observations, the IPCC concludes that “warming of the climate system is unequivocal” (IPCC 2007, Synthesis Report, Summary for Policy Makers, 2). The map on the following pages includes selected regional climate change observations from across the world, compiled by Garnaut (2008). Figure 18 Observed changes in (a) global average surface temperature, (b) global average sea level from tide gauge (blue) and satellite (red) data, and (c) Northern Hemisphere snow cover for March-April. All changes are relative to corresponding averages for the period 1961–1990. Smoothed curves represent decadal average values, while circles show yearly values. The shaded areas are the uncertainty intervals (IPCC 2007). UNIVERSITY COURSE MODULE: PLANNING FOR CLIMATE CHANGE I-42 LECTURE 1 THE SCIENCE OF CLIMATE CHANGE Figure 19 Selected regional climate change observations (from Garnaut p. 76-77) (continues next page). UNIVERSITY COURSE MODULE: PLANNING FOR CLIMATE CHANGE I-43 LECTURE 1 THE SCIENCE OF CLIMATE CHANGE Figure 19 Selected regional climate change observations (from Garnaut p. 76-77) (continued) UNIVERSITY COURSE MODULE: PLANNING FOR CLIMATE CHANGE I-44 LECTURE 1 THE SCIENCE OF CLIMATE CHANGE Climate change observed in the polar regions of the world is especially acute. Until now, the Wilkins ice shelf (one of the largest in Antarctica) has been unthreatened by the warming climate. It now appears to be breaking apart. The loss of Wilkins is alarming given that its location is further south than previously lost ice shelves. It was considered to be better protected by colder temperatures (Source: guardian.co.uk, Wednesday, March 26th, 2008). Between 1979 and 2001, there was a 20% reduction in September sea ice cover in the Arctic Ocean (Source: NASA/ Goddard Space Flight Center) and more recent images illustrate a dramatic decrease in arctic sea ice between 2006 and 2007 (Figure 20). . Figure 20 Recent and dramatic decrease in Arctic sea ice between 2006 and 2007. MODIS satellite image composites, Courtesy: A. Trichtchenko, NRCan Other indications of climate change have been observed in Greenland and the Western North Pacific. Between 1996 and 2005, Greenland experienced double the amount of historic ice loss (Error! Reference source not found.). The implications of this change are serious because open water absorbs 80% of the sun’s energy while ice reflects 80% (Campbee 2007). Hurricane power has intensified, doubling over the past thirty years in the Western North Pacific and the Atlantic. This is attributed to greater intensity and longer storms (Error! Reference source not found.). UNIVERSITY COURSE MODULE: PLANNING FOR CLIMATE CHANGE I-45 LECTURE 1 THE SCIENCE OF CLIMATE CHANGE Observations from Prehistoric Times (Paleoclimates) Scientists have constructed a history of the amount of greenhouse gases in the atmosphere over the past 420,000 years. They measured the concentrations of gases, such as CO2, in deep cores of ice taken from the Antarctic ice sheet. The ice core records showed four climate cycles; four glacial-interglacial periods with lower CO2 concentrations during the periods of glaciation. Over the past 150 years, human perturbation, e.g., industrial development and intensification of agriculture, has produced significantly higher concentrations of CO2 in the atmosphere than at any other time. (Source: http://www.in-cites.com/papers/JeanRobertPetit.html) Figure 21 below shows the atmospheric CO2 concentration from the Vostock ice core record, with the recent human perturbation superimposed. The inset shows the observed contemporary increase in atmospheric CO2 concentration from the Mauna Loa (Hawaii) Observatory. Sources: Petit et al. (1999) Nature 399, 429-436 and National Oceanic and Atmospheric Administration (NOAA), USA. Figure 21 Recent human perturbation of atmospheric CO2 concentrations. UNIVERSITY COURSE MODULE: PLANNING FOR CLIMATE CHANGE I-46 LECTURE 1 THE SCIENCE OF CLIMATE CHANGE 3. Probabilities, uncertainties and gaps in our knowledge There are many aspects of climate change as to which there remain considerable uncertainties. Uncertainty can arise for several reasons: - the nature/behaviour of certain components of the climate system are not well understood; - there is limited historical record of observations to test theories or validate models; or - the computing power required is not available. As a result, models built to simulate the climate and project future change may not align with past observations or disagree with each other, raising doubts about the likelihood of resulting scenarios. While we may expect future research and advancements in computers to reduce uncertainty, some uncertainty is inherent to dynamic, complex systems like the climate. There are simply too many relevant initial conditions and alternative pathways for any model to be able to predict the future. The behaviour of the climate system may best be described by chaos theory, especially at finer geographic scales and short time periods, the scales of greatest relevance to land use planning (Mukheibir & Ziervogel 2007). In short, uncertainty will remain irreducible and even unquantifiable to some extent. The key teaching points for planners must therefore be to be aware and alert to the sources and types of uncertainty and how they impact scientific products. Planners must be able to communicate and explain the probabilities of specific climate change outcomes to stakeholders and decision makers. Further, they must be able to suggest and support appropriate action under conditions of high uncertainty and data gaps. Methods to do this will be addressed in more detail in Lecture 4. Planners must also be concerned about the potential to understate risk of extreme events. When facing a range of possible outcomes all shrouded in uncertainty, one tendency of policy makers is to focus on medians or ‘best estimates’ or to look for the average of many projections, disregarding extremes. While by definition extremes are less likely to occur based on current assumptions, a proper assessment of risk requires that the potential for those more damaging outcomes be considered (Garnau 97). The level of certainty also varies amongst climate outcomes. Some climate variables are ‘well constrained’, including those that have a well-established response to increase global temperatures or other related parameter. Models generally agree about such projections. Examples include regional temperature response and melting of the permafrost (Garnau, 85). Other aspects of the climate system cannot be as accurately modeled. Such ‘partly constrained’ outcomes include the extent and direction of rainfall change. Finally, the response of some aspects of the climate system to increased global temperature is largely unknown. One example is the ENSO interannual anomaly, which can have significant impact on weather systems in large parts of the Earth. Scientists remain very unsure where the fluctuations will increase in frequency or intensity or perhaps decline in influence (Garnau 85). Uncertainty is also high regarding risk of extreme and abrupt climate change (recall discussion above regarding thresholds and feedbacks). In Depth Exploration Topic 3 (Sources of uncertainty) found below at page 70 provides additional details regarding the nature and extent of uncertainties in climate change science. In the following page, Figure 22 depicts some of these areas of uncertainty. UNIVERSITY COURSE MODULE: PLANNING FOR CLIMATE CHANGE I-47 LECTURE 1 THE SCIENCE OF CLIMATE CHANGE Figure 22 Probabilities, uncertainty in climate change projections There is general scientific agreement that there has been a global warming trend in the past few decades, accentuating beginning in the 1970s. The IPCC found very likely that most of the global warming has been caused by human activity since 1750. There is debate over the meaning of a temperature plateau since the early 2000s. Questions have been raised about the validity of the observations, including the effect of urban heat on monitoring stations. Most scientists express confidence that indeed the warming trend is real. Generally, certainty regarding projected change in any particular climatic variable (temperature, rain, snow cover, etc) will be much greater at global and continental scales and for longer periods of time. Conditions at regional or local scales and for shorter periods are much less certain. Significant gaps in knowledge regarding climate change impact on interannual cycles such as El Nino. The relationship between global temperature and particular climate outcomes is well understood in some respects, much less so in others. Melting glaciers and permafrost, sea level rise from ocean warming, regional temperature changes are consequences as to which there is greater confidence. Other outcomes such as rain patterns and seasonality are much less certain. The precise contribution of aerosols and clouds to radiative forcing is not well understood. There is uncertainty as well regarding the behaviour of the carbon cycle as temperatures rise. This raises doubts about the rate of climate change as global warming continues (i.e., climate sensitivity of the Earth). The IPCC’s 4th Assessment Report was most certain as to the minimum value (less than 1.5°C warming very unlikely). Anywhere from 2°C to 4.5°C was likely and higher than that could not be ruled out. Note: purpose of diagram is not to quantify confidence levels precisely or show all relationships but rather to illustrate how uncertainties and probabilities vary. UNIVERSITY COURSE MODULE: PLANNING FOR CLIMATE CHANGE I-48 LECTURE 1 THE SCIENCE OF CLIMATE CHANGE Key teaching points MAIN SOURCES AND SINKS IN CARBON CYCLE IDENTIFIED, AS WELL AS THE CONTRIBUTION FROM HUMAN ACTIVITIES (RELATIVELY SMALL BUT BELIEVED TO BE SIGNIFICANT) TWO MAIN POLICY ALTERNATIVES FOR STABILISING GHG CONCENTRATIONS: 1. DECREASE EMISSIONS (sources) 2. INCREASE UPTAKE (sinks) STABILISATION COMPLICATED BY LONG LIFETIME OF GHGS AND TIME SCALES OF CLIMATE EFFECTS (E.G. HEAT STORED IN OCEANS) MANY LINES OF EVIDENCE AND OBSERVATIONS OF CLIMATE CHANGE SUPPORT THEORY / PROJECTIONS RISK OF ABRUPT CHANGE (THRESHOLDS AND FEEDBACKS) SERIOUS CONCERN (UNCERTAINTIES ABOUND) SOURCES OF UNCERTAINTY: IMPERFECT UNDERSTANDING LIMITED RECORD OF OBSERVATIONS MODELING POWER INSUFFICIENT PROBABLITY/UNCERTAINTY OF PARTICULAR CLIMATE OUTCOMES CAN VARY SIGNIFICANTLY SOME PROJECTIONS MORE CERTAIN (E.G., LOCAL TEMPERATURE RISE), OTHERS LESS SO IN GENERAL FINER SCALES AND SHORTER TERM PROJECTIONS MORE UNCERTAIN SOME UNCERTAINTY INHERENT TO SYSTEM, IRREDUCIBLE AND UNQUANTIFIABLE ASSESSMENT OF RISK OF EXTREME OUTCOMES IS AS NECESSARY AS IT IS DIFFICULT (BEWARE TENDENCY TO ADOPT MEDIAN PROJECTIONS) ESSENTIAL FOR PLANNERS TO UNDERSTAND AND COMMUNICATE EXTENT OF UNCERTAINTY, URGE APPROPRIATE ACTION Learn more Garnau, R. (2008). "The Garnaut Climate Change Review: Understanding climate science." Retrieved 19 July 2010, from http://www.garnautreview.org.au/chp2.htm. UNIVERSITY COURSE MODULE: PLANNING FOR CLIMATE CHANGE I-49 LECTURE 1 THE SCIENCE OF CLIMATE CHANGE 4. Techniques of climate modeling As noted earlier, models are essential tools in the scientific analysis of climate change. They are computer-based representations of the climate that provide specific values or range of values for changes in the temperature, sea level rise, precipitation and other climate variables over some period of time. In this section, we discuss the techniques used to build the models most often used in climate change research, how they evolved, key assumptions built into them and some typical outputs. First, however, it is important to explain to students the significance of the model output data and terminology used by scientists to describe results. Climate model results are described as scenarios or projections. However, they are not predictions or forecasts. The distinction is important. In scientific parlance, a prediction or forecast, by definition, is the most probable outcome of future developments (ENSEMBLES 2009). It is what scientists believe will in fact happen. Generally, scientists may be able to make future predictions provided there is sufficient knowledge of the initial set of conditions and the major steering components for change in the system. Thus, generally accurate weather forecasts can be made for the next few days based on the wealth of data available about the current conditions. For very long periods of time, thousands of years, predictions of climate can also be made because major ‘steering components’ such as the orbit of the Earth can be determined with some certainty (ENSEMBLES 2009). For climate change in the scale of decades, of greatest relevance to us, prediction is impossible. Rather, Rather, scientists (using models) prepare scenarios and projections which are contingent on a set of assumption built in from the start (i.e., the extent of GHG concentrations and what an increase will mean for global average temperatures). As the assumptions are changed, different results are obtained. Thus the outputs are said to be descriptions of alternative, possible, plausible, internally consistent, but not necessarily equally probable futures. By definition a projection may in fact not be the most probable outcome. Accordingly, it is necessary to perform additional analyses of the probability of particular projections, often by reference to the agreement between various models and the extent of concordance with historic and current observations (i.e., to the extent the model’s formulas are able to mimic current and past (known) climate conditions). UNIVERSITY COURSE MODULE: PLANNING FOR CLIMATE CHANGE I-50 LECTURE 1 THE SCIENCE OF CLIMATE CHANGE a) Construction of general circulation models Models are essentially sets of mathematical equations based on the laws of physics, fluid motion and chemistry (NOAA 2008). The most commonly cited models in the climate change literature are those which mimic both oceanic and atmospheric behaviour, which are known as atmosphere-ocean general circulation models (AOGCM) or combined general circulation models (CGCM) or simply global circulation models (GCM). The model whose output was shown in Figure 2 at page 11 above is one such GCM. Note that there are many different types of climate models, not just GCMs. For each type, dozens of individual models will have been created and run, with more under development. For each model, multiple versions and many data runs may exist. CGCMs are global-scale models, meaning they project climate conditions for the entire globe. They divide the globe’s surface and atmosphere into a stacked grid of three dimensional boxes, with the side of a box typically about 200 to 300 kilometres in length. See Figure 23. A series of mathematical formulas in the model describe the relationship between the various elements of the climate system, mimicking the winds, heat transfers, radiation, relative humidity and surface hydrology within each grid and evaluating the interactions with neighbouring points. Figure 23 Schematic representation of global grid used in generating general circulation climate model. Image source: (NOAA 2008) UNIVERSITY COURSE MODULE: PLANNING FOR CLIMATE CHANGE I-51 LECTURE 1 THE SCIENCE OF CLIMATE CHANGE (Barsugli, Averyt et al. 2009) describe the basic building blocks of a climate model as follows (refer to Figure 24): In a virtual system that evolves similarly to the real world, climate models attempt to integrate all of the known factors that influence climate, from the transfer of atmospheric heat into the oceans to the reflection of solar rays by polar and mountain ice. From the climate modeler’s standpoint, the processes that control the climate can be expressed by mathematical equations derived from scientific laws, empirical data, and observations. These equations are converted into computer language and, along with information about the Earth’s geography, such as topography and vegetation, form the basis of a climate model. … “Component models” for each [part of the climate system] have been developed and are continually refined at more than a dozen scientific centers worldwide. Atmosphere models … have at their core the equations for fluid motion, which describe air movement, and the first law of thermodynamics, which relates to the conservation of energy. ... Ocean component models … simulate ocean currents, salinities, and temperatures. ... Some AOGCMS also include land surface components. Surface hydrologic processes such as evaporation, changes in snowpack, and infiltration of water into soil are typically found in these models. Figure 24 The Community Climate System Model run with the supercomputer at the U.S. National Center for Atmospheric Research incorporates data about all of the natural processes shown in this diagram. Source: http://windows2universe.org/earth/climate/ cli_models2.html&edu=high UNIVERSITY COURSE MODULE: PLANNING FOR CLIMATE CHANGE I-52 LECTURE 1 THE SCIENCE OF CLIMATE CHANGE Because conditions and events from all across the globe can affect the climate system (e.g., currents originating on the other side of an ocean), models must encompass the entire world. Further, because some conditions can affect the climate for centuries (e.g, effect of heat transfer to oceans), model runs will span decades or even centuries. This leads to a major drawback of GCMs: their coarse scale (Figure 25). Local topography, the development of thunderstorms, the presence of lakes and coastlines, the effects of large cities on temperature and precipitation, and other factors that can strongly influence local climates, and which take place at spatial scales that are smaller than a model grid box, may be missed. These processes are usually “parameterized” (i.e., the average effect of the physics of the process and its sensitivity to change are captured, but without going into the small scale details) (Barsugli, Averyt et al. 2009). The coarse spatial resolution of models makes evaluating them difficult, particularly in mountainous regions like western Canada. The large grid sizes (several thousand square miles) means that mountains are smoothed in the formulas; each gridbox with average elevations of all topography therein. Thus, snowpack, which varies from one mountain top to the next, is poorly represented (Barsugli, Averyt et al. 2009). Figure 25 The spatial detail of the early GCM map at the top left cannot match that of the regional models to its right and below it. None of them can beat the spatial detail of the map based on observations (bottom right). Image source: http://tinyurl.com/27nn69e UNIVERSITY COURSE MODULE: PLANNING FOR CLIMATE CHANGE I-53 LECTURE 1 THE SCIENCE OF CLIMATE CHANGE Scientists building a climate model make many assumptions about the internal behaviour of the climate system as well as about external influences, which assumptions are built into the mathematics of the model. Scenarios of future GHG emissions are major drivers of the current generation of climate models. Of course, the future composition of the atmosphere will depend on population growth, economic activity and the use of energy and technology, all of which drive how much GHGs we are likely to emit. Climate projections are generated for a range of emissions scenarios. For example, one scenario may be characterized by very rapid economic growth, global population peaking around 2050, and the rapid introduction of new technologies. Another scenario may include the introduction of clean and resourceefficient technology. (Warren and Egginton 2007), p. 27-56. Other natural factors, such as incoming solar radiation and volcanic aerosols, which may alter the amount of energy within the climate system and cause changes to the climate may be incorporated into the model (Barsugli, Averyt et al. 2009). UNIVERSITY COURSE MODULE: PLANNING FOR CLIMATE CHANGE I-54 LECTURE 1 THE SCIENCE OF CLIMATE CHANGE The accuracy of models is generally evaluated (validated) based on how closely the model reproduces real, observed climate statistics. Note that this is different from predicting individual events (recall difference between climate and weather). Thus, the climate models cannot reproduce a specific event such as Hurricane Katrina or the 1997–98 El Niño, but they are designed to create virtual El Niño and La Niña events that have similar magnitudes, durations, and recurrences as the real ones. Results from any one run of a climate model will likely conflict with those produced by other runs and other models. Barsugli, Averyt et al. 2009 note that: the approximately two dozen different climate models developed at the world’s climate modeling centers produce somewhat different climate states and projections of the future climate. Ultimately, the main reason for the differences among climate model results is an incomplete scientific understanding of many climate-related processes, particularly at smaller spatial scales. Even for processes that are comparatively well understood...there can be legitimate scientific differences about the best way to represent these processes in the models through parameterization. This situation has led many researchers to analyze multi-model ensembles, which are collections of simulations from many different climate models, to better encompass the range of plausible future climates. UNIVERSITY COURSE MODULE: PLANNING FOR CLIMATE CHANGE I-55 LECTURE 1 THE SCIENCE OF CLIMATE CHANGE b) Downscaling and regional climate models In order to project climate changes at finer scales, results from GCMs are ‘downscaled’ to create regional climate models (RCMs). Commonly, downscaling involves using statistical formulas that assume the existing relationships between climate at the regional and local scales will remain the same in the future. RCMs can have spatial scales as fine as 25-35 kilometres. The amount of information at this scale is much more useful and relevant to planner’s work. See Figure 24. Figure 26 Comparison of GCM and RCM spatial resolutions. Source Hadley center. RCMs take into account geographic features, such as mountains, and provide climate projections at a finer scale. Some regional models employ grid boxes as small as 50 kilometres each side of the grid box. This more detailed analysis — compared to 300 km grid boxes for GCMs — makes these models better for assessing how climate change projections may be distributed within a region. See Figure 26. However, they do have some limitations. The regional models are currently only available for a limited number of global models and emissions’ scenarios, and so do not provide as wide a range of possible projection scenarios as the global models do (Barsugli, Averyt et al. 2009). UNIVERSITY COURSE MODULE: PLANNING FOR CLIMATE CHANGE I-56 LECTURE 1 THE SCIENCE OF CLIMATE CHANGE Note that there is a connection between the spatial and time scale at which a climate condition operates and our ability to simulate it accurately using models. For those climate variables which are of a regional or global scale and which are not subject to high variability, confidence in model outputs is generally higher. Bader et al. (2008) explain the accuracy of model with respect to various climate conditions: Temperature: The seasonal cycle and large scale geographical variations of near-surface temperature are indeed well simulated in recent models, with typical correlations between models and observations of 95% or better. Precipitation: Climate model simulation of precipitation has improved over time but is still problematic. Correlation between models and observations is 50 to 60% for seasonal means on scales of a few hundred kilometers. Storms: Simulation of storms and jet streams in middle latitudes is considered one of the strengths of atmospheric models because the dominant scales involved are reasonably well resolved. As a consequence, there is relatively high confidence in the models’ ability to simulate changes in these extra tropical storms and jet streams as the climate changes ENSO: Simulations of El Niño oscillations, which have improved substantially in recent years, provide a significant success story for climate models. Extreme events: Regional trends in extreme events are not always captured by current models, but it is difficult to assess the significance of these discrepancies and to distinguish between model deficiencies and natural variability. SOURCE : http://www.climatescience.gov/Library/sap/sap3-1/final-report/sap3-1-final-all.pdf Image source: http://www2.gtz.de/dokumente/bib/gtz2009-0175en-climate-change-information.pdf UNIVERSITY COURSE MODULE: PLANNING FOR CLIMATE CHANGE I-57 LECTURE 1 THE SCIENCE OF CLIMATE CHANGE Output from climate models can be represented in a variety of formats including scatter plots, scenario maps and bioclimatic profiles. See Figure 27, Figure 28 and Figure 29. Figure 27 Scatter plot of precipitation and temperature change models for the 2050s (compared to 1961-1990) for Eastern Ontario (various models are color-coded in left hand column of lower text box) (source: NRCan 2007, Ch. 6). UNIVERSITY COURSE MODULE: PLANNING FOR CLIMATE CHANGE I-58 LECTURE 1 THE SCIENCE OF CLIMATE CHANGE Figure 28 Scenario map of July precipitation for 2011 to 2040 (compared to 1961-1990). Note large reduction in parts of BC (Model:CNRMCM3/IPT04X) (source: CCCSN (2008)). UNIVERSITY COURSE MODULE: PLANNING FOR CLIMATE CHANGE I-59 LECTURE 1 THE SCIENCE OF CLIMATE CHANGE Figure 29 Bioclimate profile for Regina, SK, projecting mean, maximum and minimum temperatures for 2041-2070 (Model: CRCM4.2.0/SR-A2, baseline period: 1961-1990 and/or 1971-2000) (source: CCCSN (2008)). UNIVERSITY COURSE MODULE: PLANNING FOR CLIMATE CHANGE I-60 LECTURE 1 THE SCIENCE OF CLIMATE CHANGE Increasingly, climate projections, based on various models and scenarios are available for downloading by the public on the web (see, e.g., CCCSN 2008). However, it may not always be easy to determine which of hundreds of model/scenario/experiment combinations for which results are available is the most accurate and relevant for the area and climate parameter under study. Planners will need to study the various assumptions built into the model as well as the probabilities associated with a particular model output. Note as well that global climate models have become more sophisticated over the last few decades, factoring a greater number of elements into climate projections. See Figure 30. Figure 30 The sophistication of models has improved since the 1970s as more elements of the climate system are incorporated into the models. UNIVERSITY COURSE MODULE: PLANNING FOR CLIMATE CHANGE I-61 LECTURE 1 THE SCIENCE OF CLIMATE CHANGE Figure 30 (continued) The sophistication of models has improved since the 1970s as more elements of the climate system are incorporated into the models. Image source: http://www.ucar.edu/news/features/climatechange/images/model_flowchart.jpg Key teaching points MAIN TYPES OF CLIMATE MODELS, HOW CONSTRUCTED, KEY ASSUMPTIONS AND MAIN OUTPUTS PROJECTION/SCENARIOS ≠ PREDICTION/FORECAST AOGCM EXPLAINED, INCLUDING COMPONENT ELEMENTS SCALE OF COVERAGE AND LIMITS IN DETAILS: GLOBAL AND REGIONAL CLIMATE MODELS DOWNSCALING TECHNIQUES TO CREATE REGIONAL CLIMATE MODELS Learn more - CCCSN (2010). "Canadian Climate Change Scenarios Network, Scenarios: Introduction." Retrieved 19 July 2010, from http://www.cccsn.ca/Scenarios/Scenarios_Introduction-e.html UNIVERSITY COURSE MODULE: PLANNING FOR CLIMATE CHANGE I-62 LECTURE 1 THE SCIENCE OF CLIMATE CHANGE C. Climate and the built environment There exists a rich body of scientific research, in the field known as urban climatology, which seeks to explain how the built environment responds to and/or interferes with climates and related bio-physical processes like soil hydration, urban heat, wind corridors and air quality (Souch and Grimmond 2006). These are the urban conditions popularly referred to as micro-climates. Planners can draw upon this knowledge to inform climate change planning proposals even when the data may be focused on current rather than future climates. Indeed, many if not all climate change proposals may be justified at least partially by reference to the need to address current climate risks with appropriate land use interventions as prescribed by urban climatologists. Thus, to the extent climate change projections may be too uncertain or politically controversial, data from the field of urban climatology may prove very useful for decision makers and advocates. In this section we provide a brief description of some of the major preoccupations, methods and findings of urban climatology and some references to the key writers in the field that should serve well as conduits for further exploration. UNIVERSITY COURSE MODULE: PLANNING FOR CLIMATE CHANGE I-63 LECTURE 1 THE SCIENCE OF CLIMATE CHANGE 1. Water, air and energy cycles in built environments Dr. Oke, a Canadian scientists and a leading figure in the field, describes urban climatology as follows: The study of urban climates is relatively young …. The field is concerned with interactions between the atmosphere and human settlements. It includes the impact of the atmosphere upon the people, infrastructure and activities in villages, towns and cities as well as the effects of those places upon the atmosphere. … [T]he term urban climate is used as an omnibus term to include the study of meteorological processes, atmospheric phenomena and the longer term amalgam expression of these as climates in areas that have undergone urban development. (Oke 2006). Of course, for many centuries it has been known that urban form and land uses can influence the local climate and how the weather is experienced by city dwellers. Early examples of climate-based town planning include the work of classical Roman architect and engineer Vitruvius (Eliasson 2000). Luke Howard’s work on the urban heat island of London, first published in 1833, is another example (Oke 1984). See Figure 31. Closer to home, the towns of Kitimat, Leaf Rapids, Inuvik and Fermont, all in Canada, were designed decades ago with consideration for extreme weather (Oke 1984). Climatic considerations for the design and layout of new areas and buildings have been part of traditional cultures throughout the world (Eliasson 2000). Modern urban climatologists apply scientific methods to analyse urban climate phenomena of various types, including those that are motion-based (or mechanical), associated with thermal flows or humidity or atmospheric in nature. See Figure 32. The time and space scales involved can vary considerably. Further, modern urban climatologists have shown that appropriate design of urban spaces and buildings can reduce human exposure and vulnerability to extreme weather and climatic conditions (Bitan 1988); (Stone and Rodgers 2001); (Taha 1997); (Bosselmann, Arens et al. 1995). As early as 1973, some urban climatologists described what they called the Meteorologically Utopian City (or ‘Metutopia’ (Landsberg 1973). Their objective was to design urban spaces and buildings so as to minimize climate stress, and to adapt human activities to the prevailing climate. Three bio-physical cycles were considered: hydrological, atmospheric and energy (or heat) cycles. Figure 33 includes a depiction of the major concerns and goals of a meteorological utopia. Notable differences exist among the various climate utopias proposed, in terms of both design elements and also perspectives and goals. The scale of primary intervention, a building, building cluster, or the entire city, has also differed. UNIVERSITY COURSE MODULE: PLANNING FOR CLIMATE CHANGE I-64 LECTURE 1 THE SCIENCE OF CLIMATE CHANGE Figure 31 This now classic image of the urban heat island above dense urban areas illustrate the often dramatic effect of urban environment on exposures to environmental conditions. http://www.london.gov.uk/lccp/ima ges/urban.gif Figure 32 The chart above shows examples of motion-based phenomena: 1) mechanical eddies shed by obstacles, 2) cross canyon vortex, 3) individual building wake, 4) chimney stack plume, 5) urban park breeze circulation, 6) urban-rural breeze system, 7) uplift in city plume, and their variable length in time and space. UNIVERSITY COURSE MODULE: PLANNING FOR CLIMATE CHANGE I-65 LECTURE 1 THE SCIENCE OF CLIMATE CHANGE While the field of urban climatology is too vast and complex to cover in much detail here, some important concepts emerging from this research are worth noting here: - The critical role of trees. Arguably, no element of the urban environment is as important to micro-climates as the tree and the urban canopy of which it is a part. Through the process of evapo-transpiration and by keeping the soil hydrated, trees cool the air close to the ground where it is most important for human comfort and health. The shading trees provide also helps to decrease building energy demand on hot days. Trees and soils also reduce storm water runoff significantly by intercepting rainwater on leaves, branches, and trunks, reducing the total amount of runoff and storm flow that must be managed in urban areas. By slowing water flow and filtering, trees also help to improve water quality. Trees remove many pollutants from the atmosphere, including nitrogen dioxide (NO2), sulfur dioxide (SO2), ozone (O3), carbon monoxide (CO), and particulate matter of ten microns or less (PM10). American Forests 2010 (http://www.americanforests.org/resources/urbanforests/naturevalue.php). - Surface permeability and reflectivity. Proper soil hydrology is important for the preservation of trees and ecosystem health, helping to cool the air and improve water quality. One critical design consideration is the extent of mineralization of surfaces in urban environments. This is also relevant to the albedo effect (defined discussed above). Dark paved materials such as asphalt absorb more solar radiation, increasing air temperatures in their immediate vicinity dramatically. - Street geometries and sky view factors. How air moves through cities can be greatly affected by the location and clustering of buildings. The angles created by building facades, particularly along streets, as well as the extent of exposure to the sky from a particular urban site are said to be important factors determining exposure to heat and poor air. Researchers have confirmed this effect in many locations, proposed design strategies to combat these effects and developed models to predict how new development may impact future climate conditions (Gonçalves dos Santos, Gazzola de Lima et al. 2003). UNIVERSITY COURSE MODULE: PLANNING FOR CLIMATE CHANGE I-66 LECTURE 1 THE SCIENCE OF CLIMATE CHANGE Figure 33 The meteorologically utopian city (after Landsberg 1973) supports and complenents the natural heat (energy), water and air cycles through carefully designed and managed land use interventions (image by author). UNIVERSITY COURSE MODULE: PLANNING FOR CLIMATE CHANGE I-67 LECTURE 1 THE SCIENCE OF CLIMATE CHANGE 2. Masking or compounding effects of urban form As awareness and concern about climate change have grown, researchers have begun to study and quantify the potential of urban design as part of an adaptation strategy. Recently, one research team demonstrated that an increase of only 10% in the vegetated surfaces in central Manchester (UK) would generate a cooling effect large enough to counteract projected temperature increases from climate change 2080 (Gill et al. 2007; (Gill, Handley et al. 2009). Essentially, residents of that city may avoid being exposed to one of the most lethal threats of climate change (increased urban heat) for decades to come by resurfacing and planting a relatively small portion of their city. However, as the effect of trees may be felt only a very short distance away, the location of new plantings must be considered carefully. Stone (2005) (Stone 2005)focused on urban heat islands, specifically their role in ozone formation and air pollution. He called for mitigation of heat islands as an effective strategy for moderating ongoing warming trends and suggested compact, moderate to high density new construction and area-based tree ordinances as policy strategies for mitigating the effects of development on climate change. Key teaching points KEY PREOCCUPATIONS AND SAMPLE FINDINGS FROM FIELD OF URBAN CLIMATOLOGY RELEVANCE OF URBAN CLIMATOLOGY RESEARCH TO CLIMATE CHANGE PLANNING Learn more - Oke, T. R. (1984). "Towards a prescription for the greater use of climatic principles in settlement planning." Energy and Buildings 7(1): 1-10. Souch, C. and S. Grimmond (2006). "Applied climatology: urban climate." Progress in Physical Geography 30(2): 270-279. Landsberg, H. (1973). "The meteorologically utopian city." Bullentin of the American Meteorological Society 54(2): 86-89. UNIVERSITY COURSE MODULE: PLANNING FOR CLIMATE CHANGE I-68 LECTURE 1 THE SCIENCE OF CLIMATE CHANGE IV. Exercises and instructional activities 1. Exercise 1 (Introductory video and quiz) The following video by National Geographic is helpful for setting the stage. Global Warming 101 http://video.nationalgeographic.com/video/player/environment/global-warmingenvironment/global-warming-101.html (3 minutes). Can be used with accompanying on-line Global Warming Quiz of about 10 min: http://environment.nationalgeographic.com/environment/global-warming/quiz-global-warming/. 2. Exercise 2 (Dimensions of climate change) Ask students to select a climate variable (temperature, rain fall, snow cover) and give two examples of climate change with respect to that variable across three dimensions (normals, variance and extremes). Make note of the day to day consequences of the various changes, in term of how weather may be experienced by residents of an area subject to this climate change. For instance, a greater range of variance in rainfall may mean that both drier and wetter July months may become typical in the area. Consider the ramifications of changing weather parameters: - What does a change in average weather conditions mean for your area? We may find, for example, that average daytime highs in July at a particular location may go up 2°C by 2030, with more rain every Spring; - What does warming mean for climate variability and how does that impact how we design and operate buildings and infrastructures? A region which in the past experienced daily lows in January typically in the range of -5°C to -10°C, may expect lows from as warm as 0 to as cold as 15°C by 2030. Note that such changes in variability may mask a change in average conditions. Because of global warming a town may experience more days of colder than normal temperatures; - Thirdly, climate change may bring more frequent, more severe or longer extreme conditions such as droughts, storms and floods. - Finally, global warming is expected to change the composition and temperature of the oceans and the extent of ground water, snow and ice. This will cause changes in sea levels, the flow of rivers and glaciers and the extent of ice fields and snow cover. 3. Exercise 3 (Extracting climate model data) The model created by the scientists at the Pacific Climate Impacts Consortium can be accessed at http://www.pacificclimate.org/tools/select. Current climate normals from Environment Canada are published here: http://www.climate.weatheroffice.gc.ca/climate_normals. Break up the class in groups of two or three students and ask each group to produce projections for a particular climate variable, location and time period, using at least two emission scenarios. Each group UNIVERSITY COURSE MODULE: PLANNING FOR CLIMATE CHANGE I-69 LECTURE 1 THE SCIENCE OF CLIMATE CHANGE should report the results in map or chart form and be prepared to explain the difference in results depending on the emission scenario used. 4. Exercise 4 (Pros/cons of LUP as a mitigation policy tool) Break up the class in two groups. Each group will be asked to consider the pros or cons of using land use planning as a mitigation policy instrument. Consider the political ramifications (cap and trade for electricity producers versus higher parking prices in congested areas), the level of government that acts, how quickly results may be achieved, etc. 5. Exercise 5 (Identify and discuss key voices on climate change) Engage students in discussion of these key voices, by asking, for example: Are you familiar with these organizations? Are there any others that you would add to the list? UNIVERSITY COURSE MODULE: PLANNING FOR CLIMATE CHANGE I-70 LECTURE 1 THE SCIENCE OF CLIMATE CHANGE V. Suggestions for in-depth exploration 1. In Depth Exploration Topic 1 (Some key climate processes) Clouds: On a cloudy day, less radiation from the sun reaches the Earth's surface and we feel cool. On the other hand, on a cloudy night the heat generated during the day is trapped and the temperature near the surface remains relatively warm. Thin cirrus clouds high up in the atmosphere let solar radiation in and trap exiting terrestrial radiation, warming the climate. Low level, thicker clouds reflect sunlight and trap little infra-red radiation. Their dominant effect is believed to be cooling the surface climate. The oceans: They take much longer to warm up than the land. They also move heat around the globe; for example, the Gulf Stream in the north Atlantic Ocean brings warm water from the tropical Atlantic up to northern Europe, and has a strong effect on the temperatures that the UK experiences. The land surface: It influences how much radiation is absorbed at the surface. An area that is covered in trees will be dark and will heat up more by absorbing more radiation. Areas covered in ice, or at the opposite extreme desert, will both reflect more radiation and absorb less heat. Aerosols: These are atmospheric particles, such as sulphate and black carbon, that are produced naturally from volcanoes and forest fires, as well as by humans from fossil fuel power stations and other industrial activities. They generally have a cooling effect on climate, by reducing the amount of sunlight reaching the surface and by changing the properties of clouds. The presence of man-made aerosols is reducing global warming in the short term. The biosphere: Plants, soils and algae absorb half of the carbon dioxide that man produces. The latest climate model predictions suggest that this will not continue indefinitely and that some parts of the biosphere (in particular soils) could start to release carbon if temperatures increase too much. Source: http://news.bbc.co.uk/2/hi/science/nature/6320515.stm UNIVERSITY COURSE MODULE: PLANNING FOR CLIMATE CHANGE I-71 LECTURE 1 THE SCIENCE OF CLIMATE CHANGE 2. In Depth Exploration Topic 2 (More facts about GHGs) Source: McKeown, A. and G. Gardner (2009). Climate change reference guide. Washington, DC, Worldwatch Institute. UNIVERSITY COURSE MODULE: PLANNING FOR CLIMATE CHANGE I-72 LECTURE 1 GLOSSARY, REFERENCES AND END NOTES 3. In Depth Exploration Topic 3 (Sources of uncertainty) One aspect of climate change theory as to which there remains considerable uncertainty is the extent of the climate sensitivity of the Earth (refer to Section III.B.1.b), The greenhouse effect, above). Scientists cannot precisely determine how much global warming will result from a specific concentration of GHGs. There is too much uncertainty regarding the magnitude of certain feedback mechanisms. Those feedbacks include the response of water vapour to increased temperatures, changes in cloud formation, and the implications of the melting of ice and snow for the amount of heat absorbed by the surface (Garnaut, 38). The range of climate sensitivity values considered likely is relatively broad, anywhere between 2 and 4.5°C increase in global temperature for a doubling of GHG concentrations. What precise value is chosen for use in a climate model can alter the results considerably. According to Bader et al. (2008) http://www.climatescience.gov/Library/sap/sap3-1/final-report/sap3-1-final-all.pdf: Uncertainties in the climatic effects of manmade aerosols constitute [another] major stumbling block...We do not know how much warming due to greenhouse gases has been cancelled by cooling due to aerosols. Uncertainties related to clouds increase the difficulty in simulating the climatic effects of aerosols, since these aerosols are known to interact with clouds and potentially can change cloud radiative properties and cloud cover. While we focus in this lecture on the uncertainties arising from lack of scientific understanding of the climate system or inherent thereto, human agency plays a key role as well (i.e., how effective will be the effort to reduce GHG emissions). This adds another dimension of uncertainty to the modeler’s work. UNIVERSITY COURSE MODULE: PLANNING FOR CLIMATE CHANGE I-73 LECTURE 1 GLOSSARY, REFERENCES AND END NOTES 4. In Depth Exploration Topic 4 (Methods of scenario construction) Types of scenarios: Development (demographic, economic, transportation) Resource utilisation GHG emissions Relevant data to consider and sources Statistical and numerical approaches to making projections Refer to the IPCC’s “Special Report Emissions Scenarios: Summary for Policy Makers”. Available at http://www.ipcc.ch/pdf/special-reports/spm/sres-en.pdf and http://www.ipcc.ch/ipccreports/specialreports.htm. The document provides a description of the different emissions’ scenarios, and explains how demographic, socioeconomic and technological development plays into the story lines. In particular, page three to the middle of page six are recommended as additional reading; pages six through twelve become more technical, and it is left to the instructor’s discretion whether to include them as part of the recommended additional reading. In summary, the report defines four story lines that characterize possible future states that will influence climate change, taking into account various patterns of demographic development, socioeconomic development and technological change. For example, story line A1 represents a future world of rapid economic growth, global population peaking mid-century followed by decline, and rapid introduction of new and efficient technologies. Story line A2 reflects continuous population growth, and slower economic growth and technological change. Each story line yields a set of scenarios for a total of 40. Scientists develop computer models of projected climate change using some or all of these scenarios. Taken together, all of the different models generate many projections, from high to low, and represent the uncertainty that exists about how climate may change in the future. UNIVERSITY COURSE MODULE: PLANNING FOR CLIMATE CHANGE I-74 LECTURE 1 GLOSSARY, REFERENCES AND END NOTES 5. In Depth Exploration Topic 5 (Statistical downscaling techniques) This approach is based on the construction of relationships between the large-scale and local variables calibrated from historical data. These statistical relationships are then applied to the large scale climate variables from an AOGCM simulation or projection to estimate corresponding local and regional characteristics. A range of methods has been developed, and is described in IPCC TAR WG1 Chapter 10 (Giorgi et al., 2001). The utility of this technique depends upon two assumptions: a) high quality large-scale and local data being available for a sufficiently long period to establish robust relationships in the current climate b) relationships which are derived from recent climate being relevant in a future climate. This last assumption appears to hold well for temperature. However, for precipitation, circulation is the dominant factor in the relationships in recent climate, whereas in a future climate, change in humidity will be an important factor. The main advantages of this approach are that it is computationally very inexpensive and it can provide information at point locations. The main disadvantages are that the statistical relationships may not hold in a future climate and that long time series of relevant data are required to form the relationships. SOURCE: http://precis.metoffice.com/docs/PRECIS_Handbook.pdf, p. 14 ADVANTAGES / DISADVANTAGES OF GCMs AND RCM GCM are starting point for all impacts studies, large-scale response to anthropogenic forcing): Advantages: information physically consistent, long simulations + different SRES scenarios, many variables, data readily available; Disadvantages: coarse-scale information for direct use in impact models where regional or local-scale climate information is essential, daily characteristics may be unrealistic except for very large regions, computationally expensive, large control run biases over heterogeneous surface conditions (e.g. Northern & Eastern Canada). Downscaling techniques: A. Regional Climate Models (i.e. dynamical downscaling): Advantages: highly resolved information, physically based, many variables, better representation of mesoscale phenomena and some weather extremes than in GCMs; Disadvantages: computationally very expensive, lack of two way nesting (feedback with the forcing GCM input), dependent on usually biased inputs from the forcing GCM, fewer scenarios available. B. Statistical downscaling: Advantages: high resolution information (grid or non-uniform regions), some techniques address diverse range of variables, variables internally consistent, computationally inexpensive, rapid application from multiple GCMs and scenarios; Disadvantages: assumption of constant empirical relationships in the future (i.e. the statistical relationships developed for the present day climate also hold under the different forcing conditions of possible future climates), demands access to daily observational surface and/or upper air data, a limited number of variables are produced using some techniques, dependent on usually biased inputs from the driving GCM. Source: http://yukon.cccsn.ca/Scenarios/From_Global_to_High_Resolution-e.html UNIVERSITY COURSE MODULE: PLANNING FOR CLIMATE CHANGE I-75 LECTURE 1 GLOSSARY, REFERENCES AND END NOTES VI. REFERENCES Barsugli, J., K. Averyt, et al. (2009). "How climate models work." Retrieved 16 July 2010, from http://www.southwestclimatechange.org/climate/modeling/how-models-work. BCEnvironment (2010). "Climate Action Secretatiat: BC Carbon Tax." Retrieved 25 June 2010, from http://www.env.gov.bc.ca/cas/mitigation/tax.html. Berke, P. R. (2002). "Does Sustainable Development Offer a New Direction for Planning? Challenges for the Twenty-First Century." Journal of Planning Literature 17(1): 21-36. Bicknell, J., D. Dodman, et al. (2009). Adapting cities to climate change : understanding and addressing the development challenges. London ; Sterling, VA, Earthscan. Bitan, A. (1988). "The methodology of applied climatology in planning and building." Energy and Buildings 11(1-3): 1-10. Blanco, H., M. Alberti, et al. (2009). "Hot, congested, crowded and diverse: Emerging research agendas in planning." Progress in Planning 71(4): 153-205. Bosselmann, P., E. Arens, et al. (1995). "Urban Form and Climate: Case Study, Toronto." Journal of the American Planning Association 61(2): 226 - 239. Breheny, M. (1996). Centrists, decentrists and compromiers: views on the future of urban form. The compact city: A sustainable urban form? M. Jenks, E. Burton and KatieWilliams. London, E & FN Spon. Davoudi, S., J. Crawford, et al. (2009). Planning for climate change : strategies for mitigation and adaptation for spatial planners. London ; Sterling, VA, Earthscan. Eliasson, I. (2000). "The use of climate knowledge in urban planning." Landscape and Urban Planning 48(1-2): 31-44. ENSEMBLES (2009). "Understanding Climate Science." Retrieved 16 July 2010, from http://www.cru.uea.ac.uk/projects/ensembles/pus/index.html. EnvironmentCanada (2008). "News Release: Government delivers details of GHG regulator framework." Retrieved June, 2010, from http://www.ec.gc.ca/default.asp?lang=En&n=714D9AAE-1&news=B2B42466-B768-424C-9A5B6D59C2AE1C36. Garnaut, R. (2008). The Garnaut climate change review : final report. Cambridge ; New York, Cambridge University Press. UNIVERSITY COURSE MODULE: PLANNING FOR CLIMATE CHANGE I-76 LECTURE 1 GLOSSARY, REFERENCES AND END NOTES Gill, S., J. Handley, et al. (2009). Planning for green infrastructure. Planning for climate change: strategies for mitigation and adaptation for spatial planners. S. Davoudi, J. Crawford and A. Mehmood. Sterling (VA), Earthscan. Gonçalves dos Santos, I., H. Gazzola de Lima, et al. (2003). "A comprehensive approach to the sky view factor and building mass in an urban area of the city of Belo Horizonte, Brazil." from http://nargeo.geo.uni.lodz.pl/~icuc5/text/P_3_12.pdf. IPCC (2007). Climate Change 2007: Synthesis Report. R. K. Pachauri and A. Reisinger. Geneva, Switzerland. IPCC (2007). Climte Change 2007: Impacts, adaptation and vulnerability (Working Group II, AR4), Appendix I:Glossary. O. F. C. M.L. Parry, J.P. Palutikof, P.J. van der Linden and C.E. Hanson. Cambridge, UK. Kropp, J. and M. Scholze (2009). Climate Change Information for Effective Adaptation. Eschborn, Germany. Landsberg, H. (1973). "The meteorologically utopian city." Bullentin of the American Meteorological Society 54(2): 86-89. McKeown, A. and G. Gardner (2009). Climate change reference guide. Washington, DC, Worldwatch Institute. Nakicenovic, N., J. Alcamo, et al. (2000). Special report on emissions scenarios : a special report of Working Group III of the Intergovernmental Panel on Climate Change. Cambridge ; New York, Cambridge University Press. NOAA (2008). "Climate model breakthroughs." from http://celebrating200years.noaa.gov/breakthroughs/climate_model/modeling_schematic.html Oke, T. R. (1984). "Towards a prescription for the greater use of climatic principles in settlement planning." Energy and Buildings 7(1): 1-10. Oke, T. R. (2006). "Towards better scientific communication in urban climate." Theoretical and Applied Climatology 84(1): 179-190. PCIC (2010). "Regional Analysis Tool." Retrieved http://www.pacificclimate.org/tools/regionalanalysis/. 24 June 2010, from Pizarro, R. E. (2009). "The mitigation/adaptation conundrum in planning for climate change and human settlements: Introduction." Habitat International 33(3): 227-229. UNIVERSITY COURSE MODULE: PLANNING FOR CLIMATE CHANGE I-77 LECTURE 1 GLOSSARY, REFERENCES AND END NOTES Smithers, J. and B. Smit (1997). "Human adaptation to climate variability and change." Global Environmental Change 7(2): 129-146. Solomon, S., D. Qin, et al., Eds. (2007). Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. New York, NY, Cambridge University Press. Souch, C. and S. Grimmond (2006). "Applied climatology: urban climate." Progress in Physical Geography 30(2): 270-279. Stehr, N. and H. Von Storch (1995). "The social construct of climate and climate change." Climate Research 5(2): 99-105. Stone, B. (2005). "Urban Heat and Air Pollution: An Emerging Role for Planners in the Climate Change Debate." Journal of the American Planning Association 71(1): 13 - 25. Stone, B. and M. O. Rodgers (2001). "Urban Form and Thermal Efficiency: <i>How the Design of Cities Influences the Urban Heat Island Effect</i>." Journal of the American Planning Association 67(2): 186 - 198. Swart, R. and F. Raes (2007). "Making integration of adaptation and mitigation work: mainstreaming into sustainable development policies." Climate Policy 7: 288-303. Taha, H. (1997). "Urban climates and heat islands: albedo, evapotranspiration, and anthropogenic heat." Energy and Buildings 25(2): 99-103. UN (1992). United Nations Framework Convention on Climate Change. New York, United Nations. Warren, F. and P. Egginton (2007). Background Information. From Impacts to Adaptation: Canada in a changing climate. D. S. Lemmen, F. J. Warren, J. Lacroix and E. Bush. Ottawa, ON, Government of Canada. UNIVERSITY COURSE MODULE: PLANNING FOR CLIMATE CHANGE I-78 LECTURE 1 GLOSSARY, REFERENCES AND END NOTES VII. END NOTES i In international agreements, climate change has come to have two different technical definitions. The UN’s Framework Convention on Climate Change, under which the Kyoto Protocol was negotiated, defines climate change as global warming caused solely by human activity. However, the UN’s Intergovernmental Panel on Climate Change (IPCC) is charged with investigating and reporting on all changes to the climate, irrespective of whether the cause is human or natural. ii The term ‘climate outcome’ is used to refer to a future climate that is one fof a range of possible outcomes for a given aspect of the climate, suich as rainfall or temperature. Garnaut p. 83. This terminology is useful to distinguish immediate physical effects of global warming from the knock on set of secondary environmental and socio-economic effects, commonly referred to as ‘impacts’. Thus, we may say that based on a particular assumptions about the climate sensitivity of the Earth system and path of GHG emissions, a rise in local summer average highs is the climate outcome, with a loss of agricultural yields as one possible impact. iii This is not to suggests that planners do not consider mitigation as being equally or more important than adaptation. Indeed, some planners may prefer to tackle mitigation and consider any attention given to adaptation to be a sign of society giving up on addressing the underlying cause of the problem. Our point here is merely that in most climate change mitigation discourses, other areas of public policy dominate, economic development, trade and industrial policy, air pollution regulations, energy and fuel production, taxation. In discussions of adaptation, however, land use and planning more generally tend to be a central focus. iv The distribution geographically and temporally of the costs and benefits associated with climate change and of adaptation and mitigation measures is uneven. This may explain the extent to which certain adaptation measures are more commonly employed. For instance, a community facing high risk of coastal erosion may be keenly interested in avoiding those effects and thus favour local adaptation measures such as building hugher sea walls. The benefit from those expenditures (that is, future harms avoided) will be reaped locally. By contrast, local expenditures to addressing the causes of global climate change (i.e., imposition of energy efficient building code that reduces electricity use and GHG emissions) would be reaped by the entire globe. v Albedo is also one factors impacting climate in urban areas. Many materials used to clad buildings and pave surfaces in urban areas, such as asphalt and roof tiles, tend to be darker and less reflective than open ground, thus absorbing more radiation and potentially generating much higher near surface temperatures. Altering albedo through white paints, the use of alternate materials and de-paving are measures which can have a substantial effect on urban heat and thus feature prominently in the adaptation agenda. The key principles of urban climatology are discussed in Section C of this Lecture. UNIVERSITY COURSE MODULE: PLANNING FOR CLIMATE CHANGE I-79