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What is Climate?

What is Climate?. Temperature near the surface of Earth:. • Seattle Annual Mean: 52˚F, 11˚C. • Global Annual Mean: 57˚F, 14˚C. Precipitation of water:. • Seattle Annual Sum: 37 inches. • Global Annual Sum: 39 inches. Washington State Annual Precipitation. Western Regional

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What is Climate?

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  1. What is Climate? Temperature near the surface of Earth: • Seattle Annual Mean: 52˚F, 11˚C • Global Annual Mean: 57˚F, 14˚C Precipitation of water: • Seattle Annual Sum: 37 inches • Global Annual Sum: 39 inches

  2. Washington State Annual Precipitation Western Regional Climate Center

  3. Annual Variation of Climate: The Annual Cycle Temperature Precipitation UW Atmospheric Sciences

  4. UW Atmospheric Sciences

  5. Temperature Extremes Maximum 100˚F July 1994 Mean 1949-2000 Minimum 0˚F Jan. 1950 1948-2000 UW Atmospheric Sciences

  6. “The Instrumental Record” ? UW Atmospheric Sciences

  7. 2001 Value = 371 0.45% per year increase recently 35% increase Since Industrial Revolution Pre-industrial Value = 275 Mauna Loa Greenland Ice Core UW Atmospheric Sciences

  8. • Vostok 3,623 meters of Ice Core ~2 Miles of Ice Core ~400,000 years of Earth History USGS

  9. Data from Petit,et al. (1999), and GISS (2003) Previous Warm Periods 2000 Previous Glacial Periods 1990 1980 1970 1960 1750 Vostok, Antarctica Ice Core UW Atmospheric Sciences

  10. What is causing the CO2 increase in the Atmosphere? A: Fossil Fuel Burning: Coal, Oil and Natural Gas. How do we know that? A1: Circumstantial Evidence of timing of increase with rise of fossil fuel use. A2: Smoking gun evidence of isotopic studies.

  11. The Carbon 14 Evidence • Carbon 14 is produced in the atmosphere by cosmic rays. • 14C is incorporated into CO2 and taken up in plants during photosynthesis • Dead plant matter is used to make Fossil Fuels • 14C is radioactive and decays with a half life of ~5,700 years Since the plant matter in fossil carbon fuels is millions of years old, it contains no 14C.

  12. The Carbon 14 Evidence 14C is decreasing with time in the atmosphere at about the right rate to be explained by fossil fuel burning. This is strong evidence that the new carbon in the atmosphere in the form of CO2 is coming from fossil fuel burning.

  13. The Carbon Budget PgC/yr in 1990’s Emissions (fossil fuel, cement) 6.3 ± 0.4 Atmospheric Increase 3.2 ± 0.1 Ocean uptake 1.7 ± 0.5 Land uptake 1.4 ± 0.7 In the 1990’s about half of the CO2 produced by human activities stayed in the atmosphere and the other half was stored in the ocean and land.

  14. Energy Flow in the Climate System UW Atmospheric Sciences

  15. UW Atmospheric Sciences

  16. Cheeka Peak Observatory Olympic Peninsula, WA UW Atmospheric Sciences

  17. Morocco Stratocumulus Canary Islands Saharan Dust over the Eastern Atlantic Ocean Saharan Dust Senegal NASA Image from MODIS Cape Verde Islands Clean Air

  18. Fires in Oregon Ship Tracks Marine Stratocumulus Clouds Smoke from Fires NASA MODIS Image July 29, 2002

  19. Forcing Climate Change Change between 1750 and present Greenhouse Gases +2.4 ± 0.2 Wm-2 (CO2, CH4, CFC, N2O) Direct Aerosol Forcing -1.0 ± 1.0 Wm-2 The forcing of climate change by humans is Uncertain primarily because of the aerosol portion. UW Atmospheric Sciences

  20. Relaxation Time Scales Carbon Dioxide: A couple hundred years. Aerosols: A couple weeks. Eventually the warming effect of CO2 and other greenhouse gases will overwhelm the cooling effect of aerosols. UW Atmospheric Sciences

  21. Climate Sensitivity Classic Climate Sensitivity Question: If we doubled the atmospheric CO2, and then waited for the climate to come into a new equilibrium, by how much would the global mean surface temperature increase? Answer: 1.5˚C to 4.5˚C or 3˚F to 8˚F Uncertain to a factor of 3! Why? UW Atmospheric Sciences

  22. Natural Feedbacks within the Climate System Water Vapor Feedback Increase Temperature Increase Water Vapor Increase CO2 +3C ~ +20% H2O Water Vapor Feedback Loop Water Vapor Feedback Approximately Doubles the Sensitivity of Climate ~1 to 2 ˚C warming

  23. Greenhouse Effect = Surface Emission - Outgoing Energy 155 Wm-2 = 390 Wm-2 - 235 Wm-2 UW Atmospheric Sciences

  24. UW Atmospheric Sciences

  25. UW Atmospheric Sciences

  26. Natural Feedbacks within the Climate System Ice-Albedo Feedback Increase Temperature Melt Surface Ice Increase Solar Absorption Ice-Albedo Feedback Loop Ice-Albedo Feedback increases the Sensitivity of Climate by 30% or so

  27. Natural Feedbacks within the Climate System Cloud Feedback Increase Temperature Change Cloud Properties Change Earth’s Energy Balance Cloud Feedback Loop Magnitude potentially large, but neither sign nor magnitude known. ? UW Atmospheric Sciences

  28. Cloud Effects on Earth’s Energy Budget 1. Clouds reflect solar radiation - a cooling effect 2. Clouds emit less energy to space than clear skies • Opaque to infrared radiation • Colder than surface because air temperature decreases with altitude. UW Atmospheric Sciences

  29. GMS-5 IR image 20˚C 0˚C IR Emission Temperature (˚K) -70˚C

  30. NASA Shuttle Photo

  31. Earth Energy Emission 150 200 250 300 UW Atmospheric Sciences

  32. Cloud Effects on the Global Energy Balance Clouds double the Earth’s albedo from 15% to 30% This results in a net loss of energy of 50 Wm-2 But cloud reduce emitted infrared radiation by 30 Wm-2 The net result of today’s clouds on the energy balance is thus a loss of 20 Wm-2 Doubling CO2 changes the energy balance by +4 Wm-2

  33. Cloud Forcing of the Energy Balance • Cover a significant fraction of the Earth’s Surface • Have a large effect on Earth’s Energy Budget -70 -30 0 +30 Wm-2

  34. Marine Boundary Layer Clouds • Cover a significant fraction of the Earth’s Surface 0 20 40 60 80% UW Atmospheric Sciences

  35. Marine Stratocumulus Reduce Energy Budget of Earth Reflect Solar Radiation Low, Warm, emit like surface

  36. Marine Boundary Layer Clouds • Cover a significant fraction of the Earth’s Surface • Have a large effect on Earth’s Energy Budget • Are Potentially sensitive to both direct human influences and to climate change. • Contribute to uncertainty about how climate will change in the future.

  37. Angola Namibia

  38. How will the Climate Change in the future? Best Available Data and Climate models Intergovernmental Panel on Climate Change IPCC

  39. Intergovernmental Panel on Climate Change Uncertain Forcing 5˚F Uncertain Feedbacks

  40. Intergovernmental Panel on Climate Change 15 Inches

  41. What would a 5˚F warming mean?

  42. What would a 5˚F warming mean? +5˚F ~ +20% vapor pressure +20% precip?

  43. What would a 5˚F warming mean? Snowline up about 1000 Feet Stevens Pass 4061 ft Snoqualmie Pass 3022 ft

  44. NASA MODIS Image July 20, 2002

  45. NASA MODIS False Color Image July 20, 2002

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