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Transcript
Climate Change: The Move to Action (AOSS 480 // NRE 480) Richard B. Rood Cell: 301-526-8572 2525 Space Research Building (North Campus) [email protected] http://aoss.engin.umich.edu/people/rbrood Winter 2010 February 2, 2010 Class News • Ctools site: AOSS 480 001 W10 • On Line: 2008 Class • Reading – IPCC Working Group I: Summary for Policy Makers Make Up Class / Opportunity • Make up Class on March 8, Dana 1040, 5:00 – 7:30 PM, Joint with SNRE 580 – V. Ramanathan, Scripps, UC San Diego – Please consider this a regular class and make it a priority to attend. Think about Projects • Today we will discuss project topics and think about teams …. – Are there groups that have self organized? • What seems especially interesting and relevant (to me)? – The near-term solution space. • What seems especially difficult to me – Carbon market versus carbon tax – Social justice as a driver of the problem versus a part of the problem What can we do now? • Some ideas – Pacala and Socolow, Science, 2004 – Socolow and Pacala, Scientific American, 2006 – Carbon Mitigation Initiative Class Projects • Think about Projects for a while – – – – – – – – – – – – The role of the consumer Energy efficiency / Financing Policy Science influence on policy, Measurements of carbon, influence Role of automobile, transportation, life style Water, fresh water, impact on carbon, Geo-engineering, public education, emergency management, warning, Water, insurance, Midwest development, Michigan, regional Dawkins, socio-biology What leads to a decision What does it really mean in the village Geo-engineering, urban sustainability US Policy, society interest, K-12, education Class Projects • Think about Projects for a while some previous ideas – Impact of local climate change efforts – Important sources of scientific uncertainty and how they impact policy – Urban planning – Geo-engineering – Natural sinks in carbon market – Ecotourism – Ecosystem services and valuation – Evaluation of Kyoto Impact – Public opinion, comparative study, impact on what we do Today • Foundation of science of climate change (continued) Some Basic References • Rood Climate Change Class – Reference list from course • Rood Blog Data Base • Koshland Science Museum: Global Warming • IPCC (2007) Working Group 1: Summary for Policy Makers • IPCC (2007) Synthesis Report, Summary for Policy Makers • Osborn et al., The Spatial Extent of 20th-Century Warmth in the Context of the Past 1200 Years, Science, 311, 841-844, 2006 Let’s Build up the Scientific Foundation • Which means lets build up – The observational foundation – The theory foundation – The validation foundation Let’s look at just the last 1000 years Surface temperature and CO2 data from the past 1000 years. Temperature is a northern hemisphere average. Temperature from several types of measurements are consistent in temporal behavior. { Note that on this scale, with more time resolution, that the fluctuations in temperature and the fluctuations in CO2 do not match as obviously as in the long, 350,000 year, record. What is the cause of the temperature variability? Can we identify mechanisms, cause and effect? How? What do we see from the past 1000 years • On time scales of, say, decades the CO2 and T are not highly correlated. • Periods on noted warmth and coolness are separated by changes in average temperature of only 0.5 F. • Changes of average temperature on this scale seem to matter to people. – Regional changes, extremes? • Recent changes in both T and CO2 are unprecedented in the past several hundred thousands of years. – And the last 10,000 years, which is when humans have thrived in the way that we have thrived. Let’s Build up the Scientific Foundation • Which means lets build up – The observational foundation – The theory foundation – The validation foundation Conservation Principle Conservation (continuity) principle • There are certain parameters, for example, energy, momentum, mass (air, water, ozone, number of atoms, … ) that are conserved. – “classical” physics, we’re not talking about general or special relativity! – Simple stuff, like billiard balls hitting each other, ice melting • Conserved? That means that in an isolated system that the parameter remains constant; it’s not created; it’s not destroyed. • Isolated system? A collection of things, described by the parameter, that might interact with each other, but does not interact with other things. Nothing comes into or goes out of the system … or, perhaps, nothing crosses the boundary that surrounds the system. Conservation (continuity) principle • There are many other things in the world that we can think of as conserved. For example, money. – We have the money that we have. • If we don’t spend money or make money then the money we have today is the same as the money we had yesterday. Mtoday = Myesterday That’s not very interesting. Conservation (continuity) principle Mtoday = Myesterday Living in splendid isolation Conservation (continuity) principle Income Mtoday = Myesterday + I - E Let’s get some money and buy stuff. Expense Conservation (continuity) principle Income Mtoday = Myesterday + N(I – E) And let’s get a car Expense per month = E Get a job Income per month = I N = number of months I = NxI and E= NxE Expense Some algebra and some thinking Mtoday = Myesterday + N(I – E) Rewrite the equation to represent the difference in money (Mtoday - Myesterday ) = N(I – E) This difference will get more positive or more negative as time goes on. Saving money or going into debt. Divide both sides by N, to get some notion of how difference changes with time. (Mtoday - Myesterday )/N = I – E Some algebra and some thinking (Mtoday - Myesterday )/N = I – E If difference does NOT change with time, then I=E Income equals Expense With a balanced budget, how much we spend, E, is related to how much we have: E = eM (Mtoday - Myesterday )/N = I – eM Some algebra and some thinking (Mtoday - Myesterday )/N = I – eM If difference does NOT change with time, then M = I/e Amount of money stabilizes Can change what you have by either changing income or spending rate All of these ideas lead to the concept of a budget: What you have = what you had plus what you earned minus what you spent Conservation Principle seems intuitive for money • The conservation principle is posited to apply to energy, mass (air, water, ozone, ... ), momentum. • Much of Earth science, science in general, is calculating budgets based on the conservation principle – What is the balance or imbalance • If balanced, then we conclude we have factual information on a quantity. • If unbalanced, then there are deficiencies in our knowledge. Tangible uncertainties. Conservation (continuity) principle EnergyIncome from the Sun Mtoday = Myesterday + I - E Earth at a certain temperature, T Let’s get some money and buy stuff. Energy emitted Expenseby Earth (proportional to T) Some jargon, language • Income is “production” is “source” • Expense is “loss” is “sink” • Exchange, transfer, transport all suggest that our “stuff” is moving around. The first place that we apply the conservation principle is energy • Assume that Energy is proportional to temperature, T, if the average temperature of the Earth is stable, it does not vary with time. Tnext year - Tlast year 0 Production - Loss change in time Production Loss And the conservation of CO2 • Assume that total CO2 is balanced. It sloshes between reservoirs and gets transported around. CO2 next year - CO2 last year change in time Production Loss 0 Production - Loss Let’s think of this as a cycle SOURCES CHANGE [CO2 ] PCO2 LCO2 t SINKS EXCHANGE Equilibrium and balance • We often say that a system is in equilibrium if when we look at everything production = loss. There might be “exchanges” or “transfers” or “transport,” but that is like changing money between a savings and a checking account. – We are used to the climate, the economy, our cash flow being in some sort of “balance.” As such, when we look for how things might change, we look at what might change the balance. Need to think about our “system” • What about carbon dioxide? What are the mechanisms for production and loss of CO2? Important things in this figure. System? • When we look at the Earth and talk about climate change what is our system? System? • When we look at the Earth and talk about climate change what is our system? Energy from the Sun Energy emitted by Earth (proportional to T) System? • But our focus is at the surface of the Earth. We change “stuff” in the system as a whole, and then we want to know how the balance of energy at the Earth’s surface will change. In both of these cases our definition of system implicitly looks at the intersection of climate and people. Energy from the Sun Energy emitted by Earth (proportional to T) One of my rules • In the good practice of science, of problem solving, to first draw a picture. Conservation (continuity) principle Energy from the Sun Stable Temperature of Earth could change from how much energy (production) comes from the sun, or by changing how we emit energy. Earth at a certain temperature, T Energy emitted by Earth (proportional to T) The Greenhouse Effect (Is this controversial?) SUN Based on conservation of energy: If the Earth did NOT have an atmosphere, then, the temperature at the surface of the Earth would be about -18 C ( ~ 0 F). Earth But the Earth’s surface temperature is observed to be, on average, about 15 C (~59 F). This greenhouse effect in not controversial. This surface temperature, which is higher than expected from simple conservation of energy, is due to the atmosphere. The atmosphere distributes the energy vertically; making the surface warmer, and the upper atmosphere cooler, which maintains energy conservation. The Greenhouse Effect (Is this controversial?) SUN Based on conservation of energy: If the Earth did NOT have an atmosphere, then, the temperature at the surface of the Earth would be about -18 C ( ~ 0 F). Earth But the Earth’s surface temperature is observed to be, on average, about 15 C (~59 F). This greenhouse effect in not controversial. This surface temperature, which is higher than expected from simple conservation of energy, is due to the atmosphere. The atmosphere distributes the energy vertically; making the surface warmer, and the upper atmosphere cooler, which maintains energy conservation. We are making the atmosphere “thicker.” Some aspects of the greenhouse effect • Greenhouse warming is part of the Earth’s natural climate system. – It’s like a blanket – it holds heat near the surface for a while before it returns to space. • Water is the dominant greenhouse gas. • Carbon dioxide is a natural greenhouse gas. – We are adding at the margin – adding some blankets • Or perhaps closing the window that is cracked open. • N20, CH4, CFCs, ... also important. But in much smaller quantities. – Molecule per molecule stronger than CO2 • We have been calculating greenhouse warming for a couple of centuries now. The first place that we apply the conservation principle is energy • If we change a greenhouse gas e.g. CO2, we change the loss rate. For some amount of time we see that the Earth is NOT in balance, that is ΔT/Δt is not zero, temperature changes. temperatur e difference T H - T time difference t H Heating Production T Cooling Loss Conservation (continuity) principle Energy from the Sun Stable Temperature of Earth could change from how much energy (production) comes from the sun, or by changing how we emit energy. Earth at a certain temperature, T Energy emitted by Earth (proportional to T) The first place that we apply the conservation principle is energy • We reach a new equilibrium T 0 H - T t Production Loss H Changing a greenhouse gas T changes this The sun-earth system (What is the balance at the surface of Earth?) SUN Based on conservation of energy: If the Earth did NOT have an atmosphere, then, the temperature at the surface of the Earth would be about -18 C ( ~ 0 F). What else could be happening in this system? Earth But the Earth’s surface temperature is observed to be, on average, about 15 C (~59 F). This greenhouse effect in not controversial. Conservation of Energy • The heating could change. That is the sun, the distance from the sun, ... . T H - T t H Heating Production Loss T Cooling Loss The first place that we apply the conservation principle is energy • We reach a new equilibrium T 0 H - T t Production Loss H T Can we measure the imbalance when the Earth is not in equilibrium? Changes in orbit or solar energy changes this Still there are many unanswered questions • We know that CO2 in the atmosphere holds thermal energy close to the surface. Hence, more CO2 will increase surface temperature. – Upper atmosphere will cool. – How will the Earth respond? • Is there any reason for Earth to respond to maintain the same average surface temperature? • Why those big oscillations in the past? – They are linked to solar variability. – Release and capture of CO2 by ocean plausibly amplifies the solar oscillation. • Solubility pump • Biological pump • What about the relation between CO2 and T in the last 1000 years? – Look to T (temperature) variability forced by factors other than CO2 • • Volcanic Activity • Solar variability • CO2 increase Radiative forcing other than CO2? – Other greenhouse gases – Aerosols (particulates in the atmosphere)