Introduction to Climate Change and its Impact on Society

1. CLIM 101: Weather, Climate and Global Society Introduction to Climate Change and its Impact on Society (lecturer) Lectures 5-6: 15, 17 Sep 2009

2. 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*

4. 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 153 Wm-2 Measured Ts = 288 K Ts (288K) > Te (255K) … Greenhouse Effect (H2O, CO2) Life on planet Earth!

5. Carbon Cycle 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)

6. Net CO2 Flux Takahashi et al. 2002

7. CO2 emissions (Gigatons of Carbon, Gt C), IPCC 2007 1990: 6.4 Gt C (=23.5 Gt CO2 ), 2000-2005: 7.2 Gt C (=26.4 Gt CO2)

8. Carbon Cycle Global Carbon Cycle (for the 1990s), IPCC AR4 The main annual fluxes in GtC yr –1 : pre-industrial ‘natural’ fluxes in black and ‘anthropogenic’ fluxes in red(modified from Sarmiento and Gruber, 2006, with changes in pool sizes from Sabine et al., 2004a).

9. Vulnerable Carbon Pools Current Global Carbon Cycle (2000-2005) After Canadell et al. 2006

10. Global Sulfur Cycle J. D. Butler, Air Pollution Chemistry, 1979.

11. Global Nitrogen Cycle [1012gN] The cycling of nitrogen is different from the cycling of water in at least one important area, which is that the "forms" of nitrogen are more varied than the form of water, which is always H2O and in either a liquid, gas, or solid form. The nitrogen cycle is complex then in part because of the many chemical forms of N such as: Organic-N; NO3; NH4; and the gases N2, N2O, NO + NO2 (=NOx). (Robarts and Wetzel, 2000 )

12. Global Nitrogen Cycle [1012gN] By K.L. Schulz

13. Changes in Greenhouse Gases From Ice Age to Modern Data

14. 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) 497-6678

15. 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)

16. 1 Ma • Mechanism: Orbital Parameters

17. 120 ka • Mechanism: Orbital Parameters

18. 18 ka

19. LAST TWO MILLENIA OR SO … 2000 Year Northern Hemisphere Reconstruction of Surface Air Temperatures Temperature Anomaly (oC)

20. LAST CENTURY OR SO …

21. What’s Happening in the Upper Atmosphere?

24. Mean of 15 Models Surface Air Temperature Difference (Sresa1b YR 71-100) minus (20c3m 1969-98), Global Average = 2.61

25. 1.0º C Courtesy of UCAR

26. Mean of 15 Models Surface Air Temperature Difference (Sresa1b YR 71-100) minus (20c3m 1969-98), Global Average = 2.61

27. (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

28. Global mean, volume mean ocean temperature Courtesy of Tom Delworth (GFDL) GFDL Model Simulations

29. 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 1906-2005 (black line) plotted against the centre of the decade and relative to the corresponding average for 1901-1950. 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.

30. Climate Model Fidelity and Projections of Climate Change J. Shukla, T. DelSole, M. Fennessy, J. Kinter and D. Paolino Geophys. Research Letters, 33, doi10.1029/2005GL025579, 2006

31. 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.”

32. IPCC Working Group 2007

33. 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 (1906-2005). • Eleven of the past twelve years are the warmest on record. • In the past 500 years, the warmest 50 years were 1951-2000.

34. 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.

35. 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 ).

36. The Unknowns • Predictability of climate models for small regions and extreme events. • Change in the frequency and intensity of tropical cyclones. • Timing for complete elimination of the Greenland ice sheet. • (sea level will rise by 7 meters) • Antarctic ice sheet : too cold?, gain mass due to more snowfall? • The probability of large abrupt climate change. • Level of warming for extinction of species • ( 1.5 – 2.5oC: 20 - 30% ; > 4oC: > 40% ) • Carbon uptake by the oceans.

37. 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

38. U. S. Flow of Raw Materials by weight 1900-2000 The use of raw materials in the U. S. increased dramatically during the last 100 years Wagner, 2002

39. THANK YOU! ANY QUESTIONS?