1. Introduction to Global Warming
CLIM 101: Weather, Climate and Global Society
Introduction to Global Warming
Jagadish Shukla
Lecture 5: Sep 15, 2009
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2. Center of Ocean-Land-Atmosphere studies
Weather
Climate
Ecosystems
Humans
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3. (sustainability, security and the future of civilization)
The Global Challenge
Global Well-Being
(sustainability, security
and the future of civilization)
Environmental
Degradation
Inequality and
Extreme Poverty
Human Population
Growth
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4. World Population World Population from AD 1 to 2002
Planet under Stress
Since 1750, population increased 10 times; Production per person also increased 10 times; Therefore, total world economic production increased 100 times.
Therefore, the impact of human activity on life-sustaining system on earth increased enormously.
World Income from 1500 to 2001
World Income per Capita from 1500 to 2001
Source: Data from Maddison (2001), Calculated using data from Maddison (2002)
‘Common Wealth’ by Jeffrey Sachs, 2008
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5. Center of Ocean-Land-Atmosphere studies
Global Poverty
From 1820 to 1992
‘Common Wealth’ by Jeffrey Sachs, 2008
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6. Examples of Short-Term Climate Variability
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7. El Nino/Southern Oscillation
1998 JFM SST [oC]
JFM SST Climatology [oC]
1998 JFM SST Anomaly [oC]

8. Summer 2003 European Heat Wave: Result of Global Warming?
The immediate cause of the heat-wave was a persistent high pressure center over Northwest Europe.
There is currently no evidence that human influence on climate makes such circulation patterns more likely.
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Summer 2003 temperatures relative to

9. Center of Ocean-Land-Atmosphere studies
LAST CENTURY OR SO …
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10. Monthly Mean Carbon Dioxide NOAA CMDL Carbon Cycle Greenhouse Gases
Atmospheric carbon dioxide mixing ratios determined from the continuous monitoring programs at the 4 NOAA CMDL baseline observations. Principal investigator: Dr. Pieter Tans. NOAA CMDL Carbon Cycle Greenhouse Gases. Boulder, Colorado. (303)
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13. LAST TWO MILLENIA OR SO …
2000 Year Northern Hemisphere Reconstruction of Surface Air Temperatures
Temperature Anomaly (oC)
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14. Center of Ocean-Land-Atmosphere studies
What’s Happening in the Upper Atmosphere?
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15. The Climate of a Planet Depends On …
Energy from the Sun
(energy from the interior)
Planetary Albedo
Speed of Planet’s Rotation
Mass of the Planet
Radius of the Planet
Atmospheric Composition
Ocean-Land, Topography S   M a
H2O, CO2, O3, clouds h*
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16. Earth’s Energy Balance
Solar Radiation
S = 1380 Wm-2
(plane, parallel)
Planetary Emission
Assume radiative equilibrium, so that
INCOMING ENERGY = OUTGOING ENERGY
Measured albedo () = 0.31
Measured planetary E = 237 Wm-2
Implied TE = 255 K
Measured surface Es = 390 Wm-2
Atmosphere absorbs Wm-2
Measured Ts = 288 K
Ts (288K) > Te (255K) …
Greenhouse Effect (H2O, CO2)
Life on planet Earth!

18. Center of Ocean-Land-Atmosphere studies
(Net) Global Warming
Warming
1. Greenhouse gases (CO2, CH4, N2O)
CO2: Carbon Dioxide : Emission from fossil fuel
CH4: Methane : Agriculture
N2O: Nitrous Oxide
2. Land use change
Cooling
Aerosols
Man made/Natural
Volcanoes
※Rate of increase of GHG is largest in 10,000 years
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19. Center of Ocean-Land-Atmosphere studies
Solar Irradiance
Recent analyses of satellite measurements do not indicate a long-term trend in solar irradiance (the amount of energy received by the sun), Frohlich and Lean (2005)
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20. Center of Ocean-Land-Atmosphere studies
Greenland Ice Mass
Greenland Grace monthly mass solutions. For the entire Greenland ice sheet, for April 2002 to April 2006, after scaling the results and removing the mean. The blue error bars include only the contributions from uncertainties in the GRACE gravity fields. Velicogna and Wahr (2006)
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Thanks: R. Cicerone

21. Current Global Carbon Cycle (2000-2005)
Pools of carbon are in Gt and annual fluxed in Gt C y-1. Background or pre-anthropogenic pools and fluxes are in black. The human perturbation to the pools and fluxed are in red. (updated from Sabine et al. 2004)
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22. Center of Ocean-Land-Atmosphere studies
CO2 emissions (Gigatons of Carbon, Gt C), IPCC 2007
1990: 6.4 Gt C (=23.5 Gt CO2 ), : 7.2 Gt C (=26.4 Gt CO2)
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23. Center of Ocean-Land-Atmosphere studies
Net CO2 Flux
Takahashi et al. 2002
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24. Changes in Greenhouse Gases From Ice Age to Modern Data
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25. Sea Level Rise over the Last Century
Climate Change, 1995
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26. Center of Ocean-Land-Atmosphere studies
Greenland Ice Mass
Greenland Grace monthly mass solutions. For the entire Greenland ice sheet, for April 2002 to April 2006, after scaling the results and removing the mean. The blue error bars include only the contributions from uncertainties in the GRACE gravity fields. Velicogna and Wahr (2006)
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Thanks: R. Cicerone

27. Annual Anomalies of Global Temperature
Figure 3.2
Relative to the 1961 to 1990 mean
Figure 3.2. Annual anomalies of maximum and minimum temperatures and DTR (°C) relative to the 1961 to 1990 mean, averaged for the 71% of global land areas where data are available for 1950 to The smooth curves show decadal variations (see Appendix 3.A). Adapted from Vose et al. (2005a).
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28. What’s Happening in the Ocean?

29. The US Historical Climatology Network (USHCN) data
Anomaly time series
The US Historical Climatology Network (USHCN) data
Figure 3.3
Relative to the 1961 to 1990 mean
Figure 3.3. Anomaly (°C) time series relative to the 1961 to 1990 mean of the full US Historical Climatology Network (USHCN) data (red), the USHCN data without the 16% of the stations with populations of over 30,000 within 6 km in the year 2000 (blue), and the 16% of the stations with populations over 30,000 (green). The full USHCN set minus the set without the urban stations is shown in magenta. Both the full data set and the data set without the high-population stations had stations in all of the 2.5° latitude by 3.5° longitude grid boxes during the entire period plotted, but the subset of high-population stations only had data in 56% of these grid boxes. Adapted from Peterson and Owen (2005).
full US Historical Climatology Network (USHCN) data
the USHCN data without the 16% of the stations with populations of over 30,000 within 6 km in the year 2000
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30. Center of Ocean-Land-Atmosphere studies
FAQ 3.1, Figure 1. (Top) Annual global mean observed temperatures1 (black dots) along with simple fits to the data. The left hand axis shows anomalies relative to the 1961 to 1990 average and the right hand axis shows the estimated actual temperature (°C). Linear trend fits to the last 25 (yellow), 50 (orange), 100 (purple) and 150 years (red) are shown, and correspond to 1981 to 2005, 1956 to 2005, 1906 to 2005, and 1856 to 2005, respectively. Note that for shorter recent periods, the slope is greater, indicating accelerated warming. The blue curve is a smoothed depiction to capture the decadal variations. To give an idea of whether the fluctuations are meaningful, decadal 5% to 95% (light grey) error ranges about that line are given (accordingly, annual values do exceed those limits). Results from climate models driven by estimated radiative forcings for the 20th century (Chapter 9) suggest that there was little change prior to about 1915, and that a substantial fraction of the early 20th-century change was contributed by naturally occurring influences including solar radiation changes, volcanism and natural variability. From about 1940 to 1970 the increasing industrialisation following World War II increased pollution in the Northern Hemisphere, contributing to cooling, and increases in carbon dioxide and other greenhouse gases dominate the observed warming after the mid-1970s. (Bottom) Patterns of linear global temperature trends from 1979 to 2005 estimated at the surface (left), and for the troposphere (right) from the surface to about 10 km altitude, from satellite records. Grey areas indicate incomplete data. Note the more spatially uniform warming in the satellite tropospheric record while the surface temperature changes more clearly relate to land and ocean.
1 From the HadCRUT3 data set.
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FAQ 3.1, Figure 1

31. Linear Tropospheric Temperature Trends
(°C per decade) for 1979 to 2005
Figure Linear tropospheric temperature trends (°C per decade) for 1979 to 2005 from RSS (based on T2 and T4 adjusted as in Fu et al., 2004a). Courtesy Q. Fu.
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32. Center of Ocean-Land-Atmosphere studies
Global Mean Sea Level
Relative to the 1980 to 1999 mean
FAQ 5.1, Figure 1. Time series of global mean sea level (deviation from the mean) in the past and as projected for the future. For the period before 1870, global measurements of sea level are not available. The grey shading shows the uncertainty in the estimated long-term rate of sea level change (Section 6.4.3). The red line is a reconstruction of global mean sea level from tide gauges (Section ), and the red shading denotes the range of variations from a smooth curve. The green line shows global mean sea level observed from satellite altimetry. The blue shading represents the range of model projections for the SRES A1B scenario for the 21st century, relative to the 1980 to 1999 mean, and has been calculated independently from the observations. Beyond 2100, the projections are increasingly dependent on the emissions scenario (see Chapter 10 for a discussion of sea level rise projections for other scenarios considered in this report). Over many centuries or millennia, sea level could rise by several metres (Section ).
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33. NH Average Snow-Covered Area (SCA)
Figure 4.2
Figure 4.2. Update of NH March-April average snow-covered area (SCA) from Brown (2000). Values of SCA before 1972 are based on the station-derived snow cover index of Brown (2000); values beginning in 1972 are from the NOAA satellite data set. The smooth curve shows decadal variations (see Appendix 3.A), and the shaded area shows the 5 to 95% range of the data estimated after first subtracting the smooth curve.
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34. Annual Minimum Sea Ice Extent (DMSP SSM/I)
Shrinking Sea Ice Extent in Arctic: Result of Global Warming?
High latitudes more vulnerable
Ice-albedo feedback
Perennial sea ice shrinking 9.6% per decade since 1979
2005
1979
Annual Minimum Sea Ice Extent (DMSP SSM/I)

35. Great Natural Disasters 1950 – 2005 Number of events
Others (Heat wave, cold wave, forest fire)
Flood
Storm
Earthquake/tsunami, volcanic eruption
© 2006 NatCatSERVICE, Geo Risks Research, Munich Re

36. U. S. Flow of Raw Materials
by weight
The use of raw materials in the U. S. increased dramatically during the last 100 years
Wagner, 2002
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37. Center of Ocean-Land-Atmosphere studies

38. Center of Ocean-Land-Atmosphere studies

40. Probability Shifting Toward Stronger Tropical Cyclones
Power Dissipitation Index (PDI) - A measure of the total power dissipated annually by tropical cyclones in the North Atlantic compared to September sea surface temperature. Note that total Atlantic hurricane power dissipation has more than doubled in the past 30 years.
See for FAQ about hurricanes and global climate change
Emanuel, Nature, 2005

41. Center of Ocean-Land-Atmosphere studies
The Knowns (Observed)
CO2 emissions have grown by 80% between 1970 and 2004.
(2005: 379 ppm; All GHG: 455 ppm (CO2 equivalent);
Primary reason: fossil fuel use and land-use change)
Rate of increase of CO2, CH4, N2O was the largest in 10,000 years.
Aerosols have partly offset the warming by CO2.
Global mean surface temp. increase (linear trend) 0.76oC in 100 years ( ).
Eleven of the past twelve years are the warmest on record.
In the past 500 years, the warmest 50 years were
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42. Center of Ocean-Land-Atmosphere studies
The Knowns (Observed)
Sea level has risen 1.8 mm/yr since 1961; 3.1 mm/yr since 1993.
Arctic sea ice extent reduced by 2.7% per decade since 1978.
(The summer minimum on record; 2007)
Enhanced run-off and earlier spring peak discharge in many glaciers and snow-fed rivers.
Extreme hot nights have increased ; frost days have decreased.
Earlier timing of spring events (blooms) on land.
Poleward and upward shifts in plant and animal ranges.
Changes in algal, plankton, and fish abundances (~Temp.).
Increase in the acidity of oceans.
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43. Center of Ocean-Land-Atmosphere studies
THANK YOU!
ANY QUESTIONS?
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44. Introduction to Global Warming
CLIM 101: Weather, Climate and Global Society
Introduction to Global Warming
Jagadish Shukla
Lecture 6: Sep 17, 2009
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47. Intergovernmental Panel
on Climate Change (IPCC)
IPCC has been established by WMO and UNEP to assess scientific, technical and socio- economic information relevant for the understanding of climate change, its potential impacts and options for adaptation and mitigation.
Working Group I: The Physical Science Basis
Working Group II: Impacts, Adaptation and Vulnerability
Working Group III: Mitigation of Climate Change
Largest number of U.S. scientists: nominated by the U.S. Govt.
Highest skepticism : “U.S. Govt.”
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48. What is a Climate Model?
Equations of motions and laws of thermodynamics to predict rate of change of:
T, P, V, q, etc. (A, O, L, CO2, etc.)
10 Million Equations:
100,000 Points × 100 Levels × 10 Variables
With Time Steps of: ~ 10 Minutes
Use Supercomputers

49. Center of Ocean-Land-Atmosphere studies
Geographic resolution characteristic of the generations of climate models used in the IPCC Assessment Reports: FAR (IPCC, 1990), SAR (IPCC, 1996), TAR (IPCC, 2001a), and AR4 (2007).
The figures above show how successive generations of these global models increasingly resolved northern Europe. These illustrations are representative of the most detailed horizontal resolution used for short-term climate simulations.
The century-long simulations cited in IPCC Assessment Reports after the FAR were typically run with the previous generation’s resolution. Vertical resolution in both atmosphere and ocean models is not shown, but it has increased comparably with the horizontal resolution, beginning typically with a single-layer slab ocean and ten atmospheric layers in the FAR and progressing to about thirty levels in both atmosphere and ocean.
Figure 1.4. Geographic resolution characteristic of the generations of climate models used in the IPCC Assessment Reports: FAR (IPCC, 1990), SAR (IPCC, 1996), TAR (IPCC, 2001a), and AR4 (2007). The figures above show how successive generations of these global models increasingly resolved northern Europe. These illustrations are representative of the most detailed horizontal resolution used for short-term climate simulations. The century-long simulations cited in IPCC Assessment Reports after the FAR were typically run with the previous generation’s resolution. Vertical resolution in both atmosphere and ocean models is not shown, but it has increased comparably with the horizontal resolution, beginning typically with a single-layer slab ocean and ten atmospheric layers in the FAR and progressing to about thirty levels in both atmosphere and ocean.
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50. Global mean, volume mean ocean temperature
Courtesy of Tom Delworth (GFDL)
GFDL Model Simulations

51. Center of Ocean-Land-Atmosphere studies
Courtesy of UCAR
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52. Mean of 15 Models Surface Air Temperature Difference
(Sresa1b YR ) minus (20c3m ), Global Average = 2.61
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53. Center of Ocean-Land-Atmosphere studies
Climate Model Fidelity and Projections of Climate Change
J. Shukla, T. DelSole, M. Fennessy, J. Kinter and D. Paolino
Geophys. Research Letters, 33, doi /2005GL025579, 2006
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54. Global and Continental Temperature Change
Comparison of observed continental- and global-scale changes in surface temperature with results simulated by climate models using natural and anthropogenic forcings. Decadal averages of observations are shown for he period (black line) plotted against the centre of the decade and relative to the corresponding average for Lines are dashed where spatial coverage is less than 50 %. Blue shaded bands show the 5-95% range for 19 simulates form 5 climate models using only the natural forcings due to solar activity and volcanoes. Red shaded bands show the 5-95% range for 58 simulations from 14 climate models using both natural and anthropogenic forcings.
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55. AOGCM Projection of Surface Temperatures
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56. Projection of Precipitation
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57. Center of Ocean-Land-Atmosphere studies
The Knowns (Models)
Limits of deterministic prediction
(attribution of an event (Katrina) is not possible)
No model can explain the past 50 year observed global warming without increase in the green house gases (GHG).
Sun and volcanoes would have produced cooling.
There is no mechanism known to scientists that can explain the global structure of warming in the A, O, L without GHG.
Warming and sea level rise would continue for centuries, even if GHG were stabilized.
Increase in the frequency of heat waves and heavy precipitation.
Entire disappearance of arctic late summer sea ice ( ~ 2100 ).
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58. Center of Ocean-Land-Atmosphere studies
THANK YOU!
ANY QUESTIONS?
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