Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
The Case for Anthropogenic Warming The Case for Anthropogenic Warming Richard McGehee Is the globe warming? What determines the Earth’s temperature? Did human activity cause the problem? How big is the problem? What’s at stake? Seminar on the Mathematics of Climate Change School of Mathematics September 9, 2009 The Case for Anthropogenic Warming What’s at stake? The Case for Anthropogenic Warming What’s at stake? The USA in the Ice Free Earth Computer Simulation, Clarence Lehman, Univ. Mn. 2006 •No ice fishing in Minnesota •No polar bears in the Arctic •No ice in Antarctica •No Florida The Case for Anthropogenic Warming The Case for Anthropogenic Warming What’s at stake? The Modern Ice Free Earth Computer Simulation, Clarence Lehman, Univ. Mn. 2006 Is the globe warming? What determines the Earth’s temperature? Did human activity cause the problem? How big is the problem? What’s at stake? Sea level rises 63 meters. 1 The Case for Anthropogenic Warming Is the Globe Warming? The Case for Anthropogenic Warming Is the Globe Warming? 2007 Polar Sea Ice Public Perception National Journal, Feb 3, 2007 http://syndication.nationaljournal.com/images/203Insiderspoll_NJlogo.pdf Press Release, 1 October 2007, National Snow and Ice Data Center http://nsidc.org/news/press/2007_seaiceminimum/20071001_pressrelease.html The Case for Anthropogenic Warming Is the Globe Warming? Polar Sea Ice Press Release, 2 October 2008, National Snow and Ice Data Center http://nsidc.org/news/press/20081002_seaice_pressrelease.html The Case for Anthropogenic Warming Is the Globe Warming? Northern Hemisphere Data http://www.ncdc.noaa.gov/paleo/globalwarming/paleolast.html The Case for Anthropogenic Warming Is the Globe Warming? Global Mean Temperature Technical Summary, IPCC AR4, p.37 http://ipcc-wg1.ucar.edu/wg1/Report/AR4WG1_Print_TS.pdf The Case for Anthropogenic Warming Is the Globe Warming? Lake Vostok http://www.nsf.gov/news/mmg/media/images/lake_vostok_nsf_h.jpg 2 The Case for Anthropogenic Warming The Case for Anthropogenic Warming Is the Globe Warming? Is the Globe Warming? Core Samples Lake Vostok Photographs copyright Reto Stöckli, NASA GSFC http://svs.gsfc.nasa.gov/vis/a000000/a000900/a000996/index.html The Case for Anthropogenic Warming The Case for Anthropogenic Warming Is the Globe Warming? Is the Globe Warming? Antarctic Temperature Data Antarctic Temperature Data 2 1.5 kiloyear bp 0 -0.5 400 350 300 250 200 150 100 50 0 4 2 0 -2 -4 -6 -8 -10 delta deg C 0.5 450 -1 temperature 1 -1.5 -8000 -7000 -6000 -5000 -4000 -3000 -2000 -1000 0 1000 -2 2000 year Petit, et al, Nature 399 (June 3 1999), pp.429-436 Petit, et al, Nature 399 (June 3 1999), pp.429-436 The Case for Anthropogenic Warming The Case for Anthropogenic Warming Is the Globe Warming? Is the Globe Warming? Ocean Temperature Data 2.5 Benthic Data (δ18 O O) 3 3 3.5 4 4.5 5 5.5 ‐4500 ‐4000 ‐3500 ‐3000 ‐2500 ‐2000 ‐1500 ‐1000 ‐500 0 time (Kyr) Lisiecki, L. E., and M. E. Raymo (2005), A Pliocene-Pleistocene stack of 57 globally distributed benthic d18O records, Paleoceanography,20, PA1003, doi:10.1029/2004PA001071. Hansen, et al, Target atmospheric CO2: Where should humanity aim? Open Atmos. Sci. J. 2 (2008) 3 The Case for Anthropogenic Warming The Case for Anthropogenic Warming What Determines the Earth’s Temperature? Is the globe warming? Heat Balance T 4 = kS What determines the Earth’s temperature? where T = surface temperature (ºK) Did human activity cause the problem? S = solar influx ((W/m2) How big is the problem? What’s at stake? k = constant depending on reflectivity of the surface, emissivity of the surface, and the Stefan-Boltzmann constant. For the current value of k , T = 255° K = −18°C = 0° F Why isn’t the Earth a Snowball? C.Lorius, The ice-core record: climate sensitivity and future greenhouse warming, Nature 347 (1990), pp.139-145 The Case for Anthropogenic Warming The Case for Anthropogenic Warming What Determines the Earth’s Temperature? What Determines the Earth’s Temperature? Heat Balance Why isn’t the Earth a Snowball? The Greenhouse Effect! J Joseph hF Fourier, i Mémoires Mé i d de l'A l'Académie dé i d des Sciences de l'Institut de France, t. vii. 1827. Svante Arrhenius, "On the Influence of Carbonic Acid in the Air upon the Temperature of the Ground," Philosophical Magazine and Journal of Science (Fifth Series) 41, pp. 237-276, 1896. Historical Overview of Climate Change Science, IPCC AR4, p.96 http://ipcc-wg1.ucar.edu/wg1/Report/AR4WG1_Print_CH01.pdf The Case for Anthropogenic Warming The Case for Anthropogenic Warming What Determines the Earth’s Temperature? What Determines the Earth’s Temperature? Radiative Forcing by Greenhouse Gases Technical Summary, IPCC AR4, p.25 http://ipcc-wg1.ucar.edu/wg1/Report/AR4WG1_Print_TS.pdf Greenhouse Gases Technical Summary, IPCC AR4, p.24 http://ipcc-wg1.ucar.edu/wg1/Report/AR4WG1_Print_TS.pdf 4 The Case for Anthropogenic Warming The Case for Anthropogenic Warming What Determines the Earth’s Temperature? What Determines the Earth’s Temperature? Atmospheric CO2 (Vostok data) 400 400 350 350 300 300 atmos CO2 (ppm m) atmos CO2 (ppm m) Atmospheric CO2 (Vostok data) 250 200 150 200 150 100 ‐450 250 100 ‐400 ‐350 ‐300 ‐250 ‐200 ‐150 ‐100 ‐50 0 ‐450 ‐400 ‐350 ‐300 ‐250 time (Kyr) ‐150 ‐100 ‐50 The Case for Anthropogenic Warming The Case for Anthropogenic Warming What Determines the Earth’s Temperature? What Determines the Earth’s Temperature? Vostok Data 150 4 200 250 0 Vostok Data CO2 (ppm) 300 CO2 (ppm) 350 400 150 200 250 300 350 400 15 2 10 0 -2 Ice Core Today -4 temperature 5 temperature Current conditions are well outside the range recorded in the ice core data. ‐200 time (Kyr) 0 Ice Core trend imbalance -5 -6 -10 -8 -15 -10 The Case for Anthropogenic Warming to be continued ... 5