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Climate Change: A Scientist’s Perspective

Climate Change: A Scientist’s Perspective Taplin Lecture Princeton Environmental Institute April 7, 2011 Ralph J. Cicerone, President National Academy of Sciences. Science and Climate Change. What is Happening? Is There an Explanation? Is There An Alternate Explanation?

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Climate Change: A Scientist’s Perspective

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  1. Climate Change: A Scientist’s Perspective Taplin LecturePrinceton Environmental InstituteApril 7, 2011 Ralph J. Cicerone, President National Academy of Sciences

  2. Science and Climate Change What is Happening? Is There an Explanation? Is There An Alternate Explanation? What Can Be Predicted?

  3. OUTLINE Earth’s Energy Balance The Greenhouse Effect Observed Changes Temperatures of Air and Water Sea-Level Rise Ice Losses from Greenland & Antarctica Future Fossil-Fuel Usage

  4. Over Earth’s history, climate has changed many times (global sea level, ice amounts, windiness, rain amounts). What forces control or influence climate? How can humans affect our planet’s climate?

  5. 239 341 H2O, CO2, O3 102 68 390 327 90 16 169 Earth receives visible light from hot Sun and Earth radiates to space as a blackbody at infrared wavelengths

  6. Infrared for Mars Te = - 28 ºC (± 5 ºC) (large day/night swings) Greenhouse effect is very small, low pressure OK ! Calculating the Surface Temperatures of Planets Visible S(1 - a) = sTe4 for Venus Actual Te = 450 ºC Greenhouse effect and clouds, high pressure for Earth, S = 341 W/m2, a = 0.3, so we calculate Te = - 18 ºC (or - 32 ºF) Greenhouse effect & clouds are needed WRONG ! WRONG !

  7. [Hanel et al. (1972)]

  8. Energy in the Climate System Averaged over the whole Earth All Human Energy Usage 0.025 watts/meter2 Extra Heat Trapped by Greenhouse gases (2007) 2.6 watts/meter2 Energy Absorbed from Sunlight 239 watts/meter2

  9. www.scrippsco2.ucsd.edu

  10. http://agage.eas.gatech.edu

  11. [Hansen and Sato (2004)]

  12. CO2 Increase is from Human Activities: Approximate Fractions • 85% from fossil fuels • 15% from deforestation

  13. http://data.giss.nasa.gov/gistemp/graphs 12 Jan 2011

  14. http://data.giss.nasa.gov/gistemp/graphs 12 Jan 2011

  15. http://data.giss.nasa.gov/gistemp/graphs/

  16. Time series of yearly ocean heat content (1022J) for the 0–700 m layer from this study (solid) and from Levitus et al. [2005a] (dashed). Each yearly estimate is plotted at the midpoint of the year. Reference period is 1957–1990. Levitus et. al. (2009)

  17. Relative Sea Level (cm) 1882-2005 sea level rise based on Permanent Service for Mean Sea Level (PSMSL) tide gauge data from 23 sites selected by Douglas (1997)This figure was prepared by Robert A. Rohdehttp://www.globalwarmingart.com/wiki/Image:Recent_Sea_Level_Rise.png

  18. Source : University of Colorado, Boulder http://sealevel.colorado.edu

  19. Greenland Mass Loss – From Gravity Satellite

  20. Greenland Ice mass loss from GRACE • Trend Apr 2002-Sep 2010: • -240±33 Gt/yr (= 0.7 mm/yr sea level rise) • ACCELERATION: -17 ±8 Gt/yr2 Velicogna (2009 GRL), updated by Velicogna (2011)  

  21. Antarctica Ice mass loss from GRACE • Trend Apr 2002-Sep 2010: • -143 Gt/yr (= 0.4 mm/yr sea level rise) • ACCELERATION: -17 Gt/yr2 Velicogna (2009 GRL), updated by Velicogna (2011)  

  22. ALL NATURAL Global annual mean surface temperature anomalies, observed and calculated. From Stott et. al. (2006)

  23. Physical Principles Explain the Warming Since the late 1970’s through the Greenhouse Effect

  24. http://data.giss.nasa.gov/gistemp/graphs 12 Jan 2011

  25. Solar irradiance through September 2008.Reference: Fröhlich, C. and J. Lean, Astron. Astrophys. Rev., 12, pp. 273--320, 2004. http://www.pmodwrc.ch/pmod.php?topic=tsi/composite/SolarConstant

  26. Global Fossil-Fuel Carbon Dioxide Emissions, 1751 to 2007Includes Cement Manufacturing All emissions estimates are expressed in million metric tons of carbon Boden & Marland (2009) cdiac.ornl.gov

  27. World marketed energy consumption, 1990-2035(quadrillion Btu) EIA, International Energy Statistics database (as of November 2009), web site www.eia.gov/emeu/international. Projections: EIA, World Energy Projection System Plus (2010).

  28. Shares of world energy consumption in the United States, China, and India, 1990-2035 (percent of world total) EIA, International Energy Statistics database (as of November 2009), web site www.eia.gov/emeu/international. Projections: EIA, World Energy Projection System Plus (2010).

  29. Coal consumption in selected world regions, 1990-2035 (quadrillion Btu) EIA, International Energy Statistics database (as of November 2009), web site www.eia.gov/emeu/international. Projections: EIA, World Energy Projection System Plus (2010).

  30. Global Carbon Cycle Management How to control the tap to avoid risk Anthropogenic Emission 7.2 GtC / y ex: 2.4-2.8℃ rise from PI 425～440ppm Dangerous Level 2ppm/y Present 380ppm industrialization 280ppm Pre-Industrial Feedback CO2 in Atmosphere Absorption 3.1 GtC/ y Ocean2.2 Land 0.9 Adapted from Nishioka, NIES, Japan

  31. In future climate: Global temperatures ? Sea-level rise ? Precipitation amounts in each region and season? Frequencies of extreme events? How to limit CO2 emissions from fossil-fuel burning?

  32. Oceans acidifying as well as warmingpH history and “business as usual” projection Red line is global annual average; blue lines show ocean-to-ocean and seasonal variation. Surface ocean pH has already fallen by 0.1 pH unit. Projected additional changes are likely to have large impacts on corals and other ocean organisms that make skeletons/ shells from calcium carbonate.

  33. Article 2, UN Framework Convention on Climate Change (1992) “The Ultimate objective of this Convention and any related legal instruments that the Conference of the Parties may adopt is to achieve, in accordance with the relevant provisions of the Convention, stabilization of greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system. Such a level should be achieved within a time-frame sufficient to allow ecosystems to adapt naturally to climate change sufficient to allow ecosystems to adapt naturally to climate change, to ensure that food production is not threatened and to enable economic development to proceed in a sustainable in a sustainable manner.”

  34. Who Should Define "Dangerous" ? scientists? elected leaders? ____________ ?

  35. Global Methane Release Rates Total = 540 Tg/yr Cicerone & Oremland, 1988

  36. Immediate action with multiple benefits. Energy efficiency would: • decrease our dependency on foreign oil • improve our national security • decrease our trade deficit • decrease local air pollution • increase our national competitiveness • encourage development of new products for global markets • decrease household energy costs while also slowing the increases of CO2 and CH4 !

  37. Evidence • Time history of CO2 increase and that of fossil-fuel usage • Amounts of atmospheric CO2 increase (0.6 x fossil-fuel emissions) • Contemporary atmospheric amounts exceed those of previous four glacial cycles • Geographical patterns of atmospheric CO2 • Isotopic contents of CO2 • Ice-core data show that CH4 and N2O amounts are also unprecedented

  38. Extreme heat waves in Europe, already 2X more frequent because of global warming, will be “normal” in mid-range scenario by 2050 Black lines are observed temps, smoothed & unsmoothed; red, blue, & green lines are Hadley Centre simulations w natural & anthropogenic forcing; yellow is natural only. Asterisk and inset show 2003 heat wave that killed 35,000. Stott et al., Nature 432: 610-613 (2004)

  39. World electricity generation by fuel, 2007-2035 (trillion kilowatthours) EIA, International Energy Statistics database (as of November 2009), web site www.eia.gov/emeu/international. Projections: EIA, World Energy Projection System Plus (2010).

  40. Renewable electricity generation in China by energy source, 2007-2035 (billion kilowatthours) EIA, International Energy Statistics database (as of November 2009), web site www.eia.gov/emeu/international. Projections: EIA, World Energy Projection System Plus (2010).

  41. World liquids consumption by region and country group, 2007 and 2035 (million barrels per day) EIA, International Energy Statistics database (as of November 2009), web site www.eia.gov/emeu/international. Projections: EIA, World Energy Projection System Plus (2010).

  42. World liquids consumption by sector, 2007-2035 (million barrels per day) EIA, International Energy Statistics database (as of November 2009), web site www.eia.gov/emeu/international. Projections: EIA, World Energy Projection System Plus (2010).

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