Download GC2 Climate

Climate Change
Greenhouse Warming
Prediction
Major information sources:
Climate Change 2001: IPCC Synthesis Report, at http://www.grida.no/climate/ipcc_tar/vol4/english/
Vital Climate Graphics, at http://www.grida.no/climate/vital/
Climate Change Impacts on US, at http://www.gcrio.org/NationalAssessment/
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Energy Consumption and C emissions, 1990-2020
(no climate policy intervention)
Carbon Dioxide Emissions
(Million Metric Tons Carbon
Equivalent)
Energy Consumption
(Quadrillion Btu)
Region
1990
1999
2010
2020
182.4
209.6
243.4
270.4
76.3
50.5
60.3
Asia
51.0
70.9
Middle East
13.1
Industrialized
EE/FSU
1990
1999
2010
2020
2,842
3,122
3,619
4,043
72.3
1,337
810
940
1,094
113.4
162.2
1,053
1,361
2,137
3,013
19.3
26.9
37.2
231
330
451
627
9.3
11.8
16.1
20.8
179
218
294
373
13.7
19.8
29.6
44.1
178
249
394
611
87.2
121.8
186.1
264.4
1,641
2,158
3,276
4,624
346.0
381.8
489.7
607.1
5,821
6,091
7,835
9,762
Developing
Africa
Central and South America
Total
Total World
Sources: History: Energy Information Administration (EIA), International Energy Annual 1999, DOE/EIA-0219(99)
(Washington, DC, January 2001). Projections: EIA, World Energy Projection System (2001).
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Major Questions
Third Assessment Report, IPCC 2001
3
Question 2
What is the evidence for, causes of, and consequences of
changes in the Earth’s climate since the pre-industrial era?
(a) Has the Earth’s climate changed since the pre-industrial era at the regional
and/or global scale? If so, what part, if any, of the observed changes can be
attributed to human influence and what part, if any, can be attributed to
natural phenomena? What is the basis for that attribution?
(b) What is known about the environmental, social, and economic
consequences of climate changes since the pre-industrial era with an
emphasis on the last 50 years?
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Question 3
What is known about the regional and global climatic,
environmental, and socio-economic consequences in the next
25, 50, and 100 years associated with a range of greenhouse
gas emissions arising from scenarios used in the TAR
(projections which involve no climate policy intervention)?
To the extent possible evaluate the:
• Projected changes in atmospheric concentrations, climate, and sea level
• Impacts and economic costs and benefits of changes in climate and
atmospheric composition on human health, diversity and productivity of
tecological systems, and socio-economic sectors (particularly agriculture and
water)
• The range of options for adaptation, including the costs, benefits, and
challenges
• Development, sustainability, and equity issues associated with impacts and
adaptation at a regional and global level
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Question 5
What is known about the inertia and time scales associated
with the changes in the climate system, ecological systems,
and socio-economic sectors and their interactions?
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Question 7
What is known about the potential for, and costs and benefits
of, and time frame for reducing greenhouse gas emissions?
• What would be the economic and social costs and benefits and equity
implications of options for policies and measures, and the mechanisms of the
Kyoto Protocol, that might be considered to address climate change
regionally and globally?
• What portfolios of options of research and development, investments, and
other policies might be considered that would be most effective to enhance
the development and deployment of technologies that address climate
change?
• What kind of economic and other policy options might be considered to
remove existing and potential barriers and to stimulate private- and publicsector technology transfer and deployment among countries, and what effect
might these have on projected emissions?
• How does the timing of the options contained in the above affect associated
economic costs and benefits, and the atmospheric concentrations of
greenhouse gases over the next century and beyond?
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Question 9
What are the most robust findings and key uncertainties
regarding attribution of climate change and regarding model
projections of:
• Future emissions of greenhouse gases and aerosols?
• Future concentrations of greenhouse gases and aerosols?
• Future changes in regional and global climate?
• Regional and global impacts of climate change?
• Costs and benefits of mitigation and adaptation options
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Integrated Framework of Climate Change
Schematic and simplified
representation of an integrated
assessment framework for
considering anthropogenic
climate change. The yellow
arrows show the cycle of
cause and effect among the
four quadrants shown in the
figure, while the blue arrow
indicates the societal response
to climate change impacts.
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Climate Feedbacks
Feedbacks in the climate system occur when the output
from one component is input into a second component,
which then generates an output altering the first component.
Example:
Increase in
Ambient Air Temperatures
Increase in
Sea-surface Temperatures
Increase in
Atmospheric CO2
Decrease in
Ocean CO2 Uptake
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The Fundamentals of Global Climate
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The Climate System
Components of the global climate system (bold), their processes and
interactions (thin arrows) and aspects that may change (bold arrows).
Climate Change 2001: The Scientific Basis; IPCC 2001
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Hadley Cells
The excess heat received in the equatorial region causes air to rise and move towards
higher latitudes. The outward motion at high latitudes near the equator has to be
balanced by inward low altitude winds. This system is a huge twin-cell circulation
pattern (one cell in each atmosphere), called Hadley Cells.
Because Earth rotates and has continental land masses, the actual prevailing winds do
not directly blow from pole to equator, but curve around and form a multicellular
circulation pattern. The curving form is called the "Coriolis effect“ and is so great as to
split up each Hadley cell into three smaller cells.
from GC1:Physical Processes
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Global air circulation and biomes
The direction of air flow and the ascent and descent of air masses in these
convective (Hadley) cells determine Earth’s general climatic zones
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Ocean Conveyer Belt
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Greenhouse Effect
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Main Greenhouse Gases
Global Warming Potential (GWP)
• used to compare the abilities of different greenhouse gases to trap heat in the atmosphere
(heat-absorbing ability and decay rate)
• provides a construct for converting emissions of various gases into a common measure
(relative toCO2)
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Greenhouse gas warming
Other
Halocarbons
5%
CFC-12
6%
Carbon
Dioxide
64%
Nitrous Oxide
6%
Methane
19%
J. T. Houghton et al., eds. Climate Change 1995: The Science of Climate Change, published for the
IPCC, in collaboration with WMO and UNEP
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Cooling Factors
19
Radiative Forcing: Cooling and Heating
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The Global Climate Record
21
400,000 years climate record
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Earth’s recent surface temperature
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Atmospheric CO2
Multi-year measurements of carbon dioxide abundances from a single location
in Hawaii, showing strong yearly signal (peak in winter months, minimum in
summer months) together with overall increase due to anthropogenic effects.
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Human influence
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Modeling Climate Change
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Modeling the Climate System
Hi all
Climate Change Impacts on the United
States, NAST, 2000.
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Climate Models:
How are they built? How are they applied?
•
•
Major components of the climate system represented in sub-models (atmosphere,
ocean, land surface, cryosphere and biosphere), along with processes within and
between them
General circulation models (GCMs)
– e.g., Atmosphere GCMs and Ocean GCMs
– equations that describe the large-scale evolution of momentum, heat and
moisture are solved in both cases
– Model resolution:
• Atmosphere GCM: ~ 250 km in the horizontal and ~ km in the vertical above
the boundary layer
• ocean GCM: ~ 125 - 250 km in the horizontal and ~ 200 to 400 m in the
vertical
• many physical processes (e.g., clouds or ocean convection) take place on
much smaller spatial scales than the model grid and therefore cannot be
modeled and resolved explicitly
their average effects are approximately included in a simple way by taking advantage of
physically based relationships with the larger-scale variables. This technique is known as
parameterization.
•
Regional circulation models (RCMs)
– smaller spatial scales allow regional variations
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Climate Models, ctn’d
• Quantitative projections of future climate change require
– models that simulate all the important processes governing the future
evolution of the climate
• atmosphere, land, ocean and sea ice
• developed separately and then gradually integrated
– considerable computing power to run comprehensive AOGCMs
• Simpler models (e.g., coarser resolution and simplified dynamics and
physical processes) are widely used
– to explore different scenarios of emissions of greenhouse gases
– to assess the effects of assumptions or approximations in model
parameters
• Simple, intermediate and comprehensive models form a “hierarchy of
climate models”, all of which are necessary to explore choices made
in parameterizations and assess the robustness of climate change
Climate Change 2001: The Scientific Basis; IPCC 2001
29
Climate Model
Short-term Climate Change from NCAR Global Circulation Model
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Comparison between Models and Observation
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Key Findings
Third Assessment Report,
Intergovernmental Panel on Climate Change
(IPCC, 2001)
32
Key Findings
 The global average surface temperature has increased over the 20th
century by about 0.6oC.
 Temperatures have risen during the past four decades in the lowest 8
kilometers of the atmosphere.
 Snow cover and ice extent have decreased.
 Global average sea level has risen and ocean heat content has
increased.
 Concentrations of atmospheric greenhouse gases and their radiative
forcing have continued to increase as a result of human activities.
Climate Change 2001: The Scientific Basis. Summary for Policymakers; IPCC 2001
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Key Findings, cnt’d
 Natural factors have made small contributions to radiative forcing over
the past century.
 There is new and stronger evidence that most of the warming observed
over the past 50 years is attributable to human activities.
 Human influences will continue to change atmospheric composition
throughout the 21st century.
 Global average temperature and sea level are projected to rise under all
IPCC SRES scenarios.
 Anthropogenic climate change will persist for many centuries.
Climate Change 2001: The Scientific Basis. Summary for Policymakers; IPCC 2001
34
Scenarios
35
Scenarios
What are they? Why use them?
• neither predictions nor forecasts
• alternative images of how the
future might unfold
• an appropriate tool with which to analyze how driving
forces may influence future emission outcomes and to
assess the associated uncertainties
IPCC Special Report on Emission Scenarios
36
A1 Storyline and Scenario Family
A world with:
• very rapid economic growth
• low population growth
• rapid introduction of new and
more efficient technologies
Major Underlying Themes:




convergence among regions
capacity building
increased cultural and social interactions
substantial reduction in regional differences in per capita income
Alternative directions of technological change
 A1FI - high coal and high oil and gas
 A1B - balanced (even distribution among options)
 A1T - predominantly non-fossil fuel
IPCC Special Report on Emissions Scenarios
37
A2 Storyline and Scenario Family
A highly heterogeneous world with:
 high population growth (due to slow convergence of fertility
patterns across regions)
 regionally-oriented economic development
 per capita economic growth more fragmented/slower
 technological change more fragmented/slower
Major underlying themes:
 self reliance
 preservation of local identities
IPCC Special Report on Emissions Scenarios
38
B1 Storyline and Scenario Family
A convergent world with:
• rapid changes in economic structures toward a service and
information economy
• low population growth (same as A1)
• reductions in material intensity
introduction of clean and resource-efficient technologies
Major Underlying Themes:
 global solutions to economic, social,
and environmental sustainability
(without additional climate initiatives)
 improved equity
IPCC Special Report on Emissions Scenarios
39
B2 Storyline and Scenario Family
A world with:
• intermediate levels of economic
development
• moderate population growth
• reductions in material intensity
• less rapid and more diverse
technological change
Major Underlying Themes:
 local solutions to economic, social, and environmental
sustainability (without additional climate initiatives
 social equity (with local/regional focus)
 environmental protection (with local/regional focus)
IPCC Special Report on Emissions Scenarios
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Scenarios
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Projections for the 21st Century
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The Emission scenarios and their implications for
atmospheric composition, climate, and sea level
Date
Global
Population
(billions)a
Global
GDP
(1012
US$/yr)b
Per
Capita
Income
Ratioc
GroundLevel O3
(ppbv)d
Global
Global
Temperature Sea-Level
Change
Rise (cm)g
( C)f
CO2
(ppmv)e
1990
5.3
21
16.1
---
354
0
0
2000
6.1 – 6.2
5 – 28
12.3 – 14.2
40
367
0.2
2
2050
8.4 – 11.3
59 – 187
2.4 – 8.2
~60
463 – 623
0.8 – 2.6
5 – 32
2100
7.0 – 15.1
197 - 550
1.4 – 6.3
>70
478 - 1099
1.4 – 5.8
9 - 88
Technical Summary Climate Change 2001: Impacts, Adaptation, and Vulnerability; IPCC 2001
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Effect of Time Scale
After CO2 emissions are reduced and atmospheric concentrations stabilize, surface air
temperature continues to rise slowly for a century or more. Thermal expansion of the
ocean continues long after CO2 emissions have been reduced, and melting of ice sheets
continues to contribute to sea-level rise for many centuries. (Illustration for stabilization at
level between 450 and 1,000 ppm.)
Climate Change 2001: Synthesis Report; IPCC 2001
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Stabilization
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Potential Impacts of Climate Change
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Climate Model
Short-term Climate Change from NCAR Global Circulation Model
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Climate Change Impacts
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Thinning of Arctic Sea Ice
Ice Melting:
• glaciers and ice caps: .5m
• Greenland ice sheet: 7m
• Antarctic ice sheet: 70m
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Sea Level Rise
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Sea level rise: examples
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Extreme Weather
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Precipitation
and Freshwater
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Health and Climate Change
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Dengue Fever and Temperature Rise
CLINICAL FEATURES
Sudden onset of fever, severe headache, myalgias and arthralgias,
leukopenia, thrombocytopenia and hemorrhagic manifestations
Occasionally produces shock and hemorrhage, leading to death
Globally, there are an estimated 50 to 100 million cases of dengue
fever (DF) and several hundred thousand cases of dengue
hemorrhagic fever (DHF) per year
Average case fatality rate of DHF is about 5%
http://www.cdc.gov/
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Regional Analysis
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Climate Change Impacts on the United States: The
Potential Consequences of Climate Variability and Change
The objectives of the National Assessment:
•
to synthesize, evaluate and report on what we presently know about the potential
consequences of climate variability and change for the United States in the 21st
century
•
to identify key climatic vulnerabilities of
particular regions and sectors
-in the context of other changes in the
nation’s environment, resources, and
economy
•
to identify the highest priority
uncertainties about which we must
know more to understand climate
impacts, vulnerabilities, and our ability
to adapt
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Climate Change Impacts on the United States
Regional Evaluations and Sectors
Regions
Northeast
Southeast
Midwest
Great Plains
West
Pacific Northwest
Alaska
Islands
Sectors
Agriculture
Forests
Water
Coastal Areas and Marine Resources
Human Health
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The Analysis Process
• State-of-the-science climate
models were used to generate
climate change scenarios:
– Hadley Center, United Kingdom
– Canadian Centre for Climate
Modeling and Analysis
– AND
• The National Center for Atmospheric Research, USA
• NOAA Geophysical Fluid Dynamics Laboratory, USA
• NASA Goddard Institute for Space Studies, USA
• Models used to study systems responses to the
climate change scenarios:
– Ecological systems
– Hydrological systems
– Socioeconomic systems
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21st C growth in the US
The assessment considered high,
medium, and low scenarios of future U.S.
population and economic growth.
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Temperature and Heat Predictions
61
Agriculture and Forest Sectors
62
Water, Coastal Areas and Marine Resources
63
Health Sector
64
65
All the
All
66
Key Findings
67
Source: Climate Change Impacts on the United States, NAST Overview, 2000.
Key Findings, ctn’d
68
Source: Climate Change Impacts on the United States, NAST Overview, 2000.
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Today
• The earth is warming, unambiguously. Surface air temperature records, radiosonde data, and satellite
observations all show this has been happening for several decades; there is disagreement over the magnitude
of the warming.
• This warming is unprecedented in historical times. Warming in the NH (northern hemisphere) over last 100 yrs.
has been greater than any over last thousand. 1998 was the warmest year of the millennium.
• There is evidence, independent of temperature recordings, that the planet is warming. Snow cover, glaciers,
spring and summer sea ice are all decreasing and/or receding.
• There are a few opposing data points. For example, parts of Antarctica are not warmer.
• Other parts of the climate system have been affected. Precipitation and cloud cover have increased over the
mid to high latitudes in the NH, and have decreased in NH subtropics. El Ninos are more frequent, and
droughts are more common in Africa and Asia.
• Sea level has risen 10-20cm during 20th century. Half of this expansion is due to thermal expansion. The other
half is from glacial melting.
• Anthropogenic effects are indeed increasing the levels of greenhouse gases. For example, CO2 has increased
by 31% since 1750; ¾ of this increase is due to fossil fuels. Methane (CH4) has increased by 151%; ~1/2 of
which is due to anthropogenic emissions.
• This has had a radiative effect. From 1750-2000, there has been a warming of 2.78 W/m2.
• Man has also produced some cooling influences, for example, -0.65W/M2 cooling has been observed, mostly
from sulfate aerosols and stratospheric O3 reduction.
• Natural variability is probably a small factor here. More important locally than globally.
• Conclusion: Humanity is likely responsible for the warming.
70
Tomorrow?
• Greenhouse gases are projected to increase over the next century. Carbon cycle projections show an increase
of 50-170% for CO2 alone.
• Aerosol projections vary. Sulfate aerosols should decrease; natural and carbon aerosols most will increase.
• Radiative forcing will increase, primarily from CO2 emissions.
• Surface air temperature will increase an estimated 1.4 -5.8 degrees Celsius globally.
• Even the low estimate would be unprecedented for the last 10,000 yrs.
• Areas will not warm equally. Increased warming over land, particularly in high northern latitudes, in winter.
Possibly 40% greater.
• Ocean circulation may change. El Niño events may increase in freq; North Atlantic circulation could change,
mitigating warming of Western Europe.
• Water availability may change influenced by both heavier rainfall and severe droughts. Wetter at high latitudes,
drier in mid latitudes during summer.
• Severe storms will probably increase.
• Snow cover, sea ice cover, glaciers, and ice caps should decrease.
• Sea level rise projections vary greatly. From 1990-2100, 10-90 cm is possible.
• The effects last an unknown amount of time. Even if greenhouse gas emissions were suddenly stabilized, higher
levels of CO2 would persist for hundreds of years, and with that, continued increase in temp and sea level; most
disconcerting is that ice sheet changes could last thousands of years with potential sea level rise of up to 10m.
• Steps necessary to stabilize CO2 levels depend on the level desired. To achieve 450 ppm CO2 levels, we would
have to go below 1990 emissions; in order to stabilize CO2 levels at twice current levels, we would have to do
nothing for one century.
• Confidence levels of the above projections vary, but it is certain that there will be continued warming, sea level
rise, and amplification of the hydrologic cycle.
71