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NASA

NASA. Global Warming 101. Roy W. Spencer, Ph.D Principal Research Scientist The University of Alabama In Huntsville 19 March 2007. Height . Due to greenhouse effect. Temperature . We are probably not as warm as during Medieval Warm Period.

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NASA

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  1. NASA

  2. Global Warming 101 Roy W. Spencer, Ph.D Principal Research Scientist The University of Alabama In Huntsville 19 March 2007

  3. Height Due to greenhouse effect Temperature

  4. We are probably not as warm as during Medieval Warm Period The GRIP (Greenland) borehole record is one of the best records because it is not a proxy, it is a DIRECT measure of temperature.  Shown are the last 2000 years. (Dahl-Jensen et al. 1998, Science, 282, 268-271 "Past Temperatures Directly the Greenland Ice Sheet").  A similar reconstruction occurs for the Ural Mountain borehole temperatures (i.e. warmer 1000 years ago, Bemeshko, D., V.A. Schapov, Global and Planetary Change, 2001.

  5. Global Warming Basic Hypothesis: • Carbon Dioxide is a greenhouse gas, • it is increasing in the atmosphere (at ½ rate of human production), • therefore, the lower atmosphere MUST warm CO2 concentration is now about => 40% above pre-industrial times.

  6. Most of our atmosphere is being continuously recycled by precipitation systems, which then determine the strength of the Greenhouse Effect Cooling (loss of IR radiation) by dry air to space Heat released through condensation causes air to rise, rain falls to surface Air sinks in response to precipitation systems: Sinking air is relatively dry Sunlight absorbed at surface Boundary layer warm, humid air cool, dry air evaporation removes heat Ocean or Land

  7. Outline • Evidence for climate change • Predictions of future climates • Assessing response of natural ecosystems • Future directions

  8. GLOBAL WARMING BASICS: “Radiative Energy Balance” (= const. Temp.) Incoming Sunlight Emitted Infrared Radiation = Global average input = output = ≈235 Watts per square meter => Greenhouse gases affect Infrared Radiation

  9. “Global Warming”(at least since 1920)is Real… But how unusual is it? How much of it is natural versus man-made? Data source: J. Hansen/ GISS “Little Ice Age”

  10. Niagara Falls NY - 1911

  11. Spreading disease Coral reef bleaching Heat waves and periods of unusually warm weather Downpours, heavy snowfalls, and flooding Glaciers melting Earlier spring arrival Plant and animal range shifts and population declines Sea level rise and coastal flooding Arctic and Antarctic warming Droughts and fires GLOBAL WARMING: Early Warning Signs http://www.climatehotmap.org/ Fingerprints and Harbingers

  12. Changes in surface temperatures US 20th century Global 20th century °F

  13. A 1000-year record of temperatures

  14. Borehole temperatures

  15. Retreat of glaciers Grinnell glacier, 1938 Grinnell glacier, 1981

  16. Retreat of glaciers

  17. Sea ice extent and mass

  18. Coral reef bleaching Bleaching hot spots in last 15 years Bleached Goniopora coral, Micronesia

  19. Rising sea levels

  20. Rising sea levels

  21. Rising sea levels

  22. Insect pests and disease

  23. Changes in growing season length Mauna Loa, HI Thoning and Tans

  24. Changes in US precipitation regimes % 20th c.

  25. Arctic Climate Impact Assessment (ACIA) Sources: Claire Parkinson and Robert Taylor

  26. Greenland Mass Loss – From Gravity Satellite

  27. Responsibility for CO2 Emissions and Climate Change

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