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Climate Change

Climate Change. What Does the Science Really Tell Us?. Craig Cogger WSU Puyallup. Simplified Greenhouse Effect. Energy radiates back toward space as lower-energy infrared waves. Greenhouse gases absorb and re-radiate some of the infrared energy, trapping heat in the atmosphere. . 2. 3. 1.

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Climate Change

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  1. Climate Change What Does the Science Really Tell Us? Craig Cogger WSU Puyallup

  2. Simplified Greenhouse Effect • Energy radiates back toward space as lower-energy infrared waves • Greenhouse gases absorb and re-radiate some of the infrared energy, trapping heat in the atmosphere. 2 3 1 Solar energy passes through atmosphere and is absorbed by the earth

  3. Greenhouse Gases • CO2, H2O, N2O, CH4:Absorb infrared energyAct like a blanket • Without the greenhouse effect, earth’s mean temperature would be 0o F, nearly 60o lower than it is now Carbon Dioxide Water

  4. The Problem:We are increasing atmospheric CO2, adding to the greenhouse effect, and warming the planet

  5. Some of the Complicating Details Atmospheric Circulation moves heat NASA Carbon Cycle moves, transforms, and stores CO2 G. Holloway, Institute of Ocean Sciences, Sidney, BC UCAR USDOE PNNL Aerosols interact with solar energy Ocean Circulation moves and stores heat and CO2

  6. Definitions:Weather and Climate • Weather: The current state of the atmosphere (hours, days, weeks, months) • Climate: Average weather over time (30 years or more) • Climate is what you expect, weather is what you get San Antonio Daily San Antonio Daily

  7. Weather: Climate: http://data.giss.nasa.gov/gistemp/graphs/

  8. Climate Forcing • Climate forcing: Affects global energy balance, forcing a change in climate • Examples: • Changes in solar energy (sunspot cycles, orbital changes – small over short time scales) • Changes in greenhouse gas concentrations (CO2, CH4, N2O, others) • Aerosols NOAA USGS USGS Minnesota public radio

  9. Climate FeedbackAmplifies or dampens climate forcing • H2O in atmosphere: Positive feedback, increases warming • Snow and ice melting: Positive feedback – more melting, less reflection of heat, more warming • Melting permafrost and thawing soil releasing greenhouse gases: Positive feedback • Changes in cloud cover: Both positive and negative NASA UNEP Katey Walter, UAF Jon Sullivan

  10. Evidence for Current Climate Change:Temperature Anomalies http://data.giss.nasa.gov/gistemp/graphs/

  11. Evidence for Current Climate Change:Temperature Extremes – US 48 states www.ucar.edu

  12. Evidence for Current Climate Change:Sea Ice Extent

  13. Evidence for Current Climate Change:AcceleratingGlacier Loss USGS

  14. Evidence for Current Climate Change:Ecosystem Changes • Bleached coral reef • Coral death and decline appear linked to increased water temperatures • Pine bark beetle damage • Extreme cold keeps beetle populations in check. Recent severe infestations appear related to moderating winter temperatures NOAA US Forest Service

  15. Evidence for Current Climate Change:Sea Level Rise http://sealevel.colorado.edu/

  16. Evidence for Current Climate Change: http://www1.ncdc.noaa.gov/pub/data/cmb/bams-sotc/2009/bams-sotc-2009-brochure-lo-rez.pdf

  17. IPCC Regional Temperature ProjectionsChange compared with 1980-1999 baseline IPCC 4th Assessment

  18. IPCC Regional Precipitation Projections for 2090-2099Compared with 1980-1999 baseline IPCC 4th Assessment

  19. Land at risk from 1m sea level rise SaifulHuq Omi/Polaris, for The New York Times

  20. Isn’t there another point of view? Not one with a credible scientific basis. Watts Up With That? Commentary on puzzling things in life, nature, science, weather, climate change, technology, and recent news by Anthony Watts

  21. The Global Challenge • 86% of world’s energy comes from fossil fuel • Deforestation is #2 human source of CO2 • Target 80% reduction in CO2 emissions by 2050 to avoid worst outcomes of climate change • Individual and government action needed

  22. Responding to the climate change challenge We basically have three choices: mitigation, adaptation and suffering. We’re going to do some of each. The question is what the mix is going to be. The more mitigation we do, the less adaptation will be required and the less suffering there will be. John Holdren

  23. The “Wedge Strategy” for Mitigation • Each wedge plays a role in reducing greenhouse gas emissions • Think of how our industry can contribute to these wedges. NRDC

  24. Getting Involved • Reduce emissions at home and work • Learn more about climate science • Talk to your friends, neighbors, and co-workers • Write to decision makers • Support organizations who work for those in greatest need

  25. Take-home message • Greenhouse effect • Science is unassailable: Added greenhouse gases warm the earth • Multiple lines of evidence show effects of warming across the globe • We need to act now to avoid the most severe harm to people and the environment.

  26. Looking to the future:Many of the youngest among us will still be alive in the closing decades of this century. How can we shape the world will they be living in?

  27. Recommended Reading IPCC synthesis of the best science, 2007 (already a little out-of-date) Readable, robust science, 2009 Well written by a physicist/historian, 2008 Trustworthy climate science blogs

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