The Science of Climate Change

1. Jeff Lewis The Science of Climate Change

2. Where do we learn about global warming? The Media!

3. Sunday, January 14, 2001 Tuesday, January 23, 2001

4. Good Information Intergovernmental Panel on Climate Change (IPCC)www.ipcc.ch Environment Canada http://www.ec.gc.ca Arctic Climate Impact Assessment (ACIA) www.amap.no/acia/index.html Kyoto Protocol unfccc.int/resource/convkp.html

5. Overview • What is climate change and global warming? • Recent history of climate change • Anthropogenic (human induced) climate change • Projections of future climate change • Climate feedbacks • The Kyoto Protocol • A climate success story

6. What is Climate Change? “Climate is what you expect, weather is what you get” Climateis the “average weather” Climate Changeis a “change in the average weather” Global Climate Changewill affect different regions of the world in different ways

7. What is Global Warming? • Increase in Earth’s mean temperature due to an increase in atmospheric greenhouse gases • Increasing C02 amplifies the greenhouse effect Enhanced greenhouse effect

8. Medieval Warm Period Norse western settlement of Greenland abandoned (1350) Norse settlement of Greenland (980) Recent History of Climate Change Temperature anomalies in the Northern Hemisphere over the last 1000 years Little Ice Age

9. Medieval Warm Period The great famine (1315-21) Pieter Bruegel (1565) Recent History of Climate Change Temperature anomalies in the Northern Hemisphere over the last 1000 years Little Ice Age

10. The Hunters in the Snow, Pieter Bruegel, 1565

11. CH4 = 1750 ppb A 420,000 year record of CO2, CH4 and inferred Antarctic Temperature CO2 = 375 ppm

12. Long-Term Temperature Trends Over the last 1000yrs the global mean temperature was decreasing until the 1900s

13. THE TOP 10 1: 1998 2: 2003 3: 2002 4: 2001 5: 1997 6: 1995 7: 1990 8: 1999 9: 2000 10: 1991 Warming over the last 100 years

14. Intergovernmental Panel on Climate Change (IPCC) • Established by the World Meteorological Organization (WMO) and the United Nations Environment Program (UNEP) in 1988 • Does NOT carry out research or monitor climate data • Undertakes an assessment of the peer-reviewed scientific literature www.ipcc.ch Working Group I (WGI): Science Working Group II (WGII): Socioeconomic impacts and adaptation Working Group III (WGIII): Mitigation

15. IPCC Summary for Policy Makers (Working Group I) IPCC 1996 “The balance of evidence suggests a discernible human influence on global climate” IPCC 2001 “There is now new and stronger evidence that most of the warming observed over the last 50 years is attributable to human activities”

16. Can models reproduce the climate of the 20th Century? Model Observations

17. Anthropogenic Climate Change

19. Greenhouse Gases Main Greenhouse Gases H2O – Water Vapour CO2 – Carbon Dioxide CH4 – Methane N2O – Nitrous Oxide O3 – Ozone (Troposphere) CFCs – Chloro-fluorocarbons Longwave Absorption Band N2O O3 CO2 H2O

20. Contribution to the Greenhouse Effect (including water vapor) Water vapour is the most dominant greenhouse gas

21. Contribution to the Greenhouse Effect (without water vapour) Carbon dioxide is the second most dominant greenhouse gas

22. Direct Global Warming Potential relative to carbon dioxide Global Warming Potential

23. Greenhouse Gases Carbon Dioxide Highest amountof greenhouse gases in last 1000 years Methane Nitrous Oxide

24. Greenhouse Gases Carbon Dioxide Methane Nitrous Oxide

25. Greenhouse Gas Emissions In Canada

26. CO2 = 486–1248 ppm CH4 = 1750–3731 ppb The influence of humans on climate evolution What about concentrations in the year 2100?

27. Land-Use Change Loss of vegetation burning releases CO2 Leads to warming More reflective ground less sunlight absorbed Leads to cooling

28. Projections of future climate The Emissions Scenarios Carbon Dioxide Emissions Atmospheric Carbon Dioxide Concentration Atmospheric Sulphur Dioxide Concentration Also done for other greenhouse gases (methane, nitrous oxide etc)

29. Projections of future climate — Year 2100 Global Mean Temperature Global Mean Sea Level 9 – 88 cm increase 1.4 – 5.8°C increase

30. Projections of future climate (Annual Mean Temp. Change) Years 2071–2100 relative to years 1961–1990

31. Climate Feedbacks Water Vapour (positve feedback) Temperature increases Atmosphere More H2O Enhanced greenhouse effect More evaporation Ocean Land More water vapour in the atmosphere

32. Climate Feedbacks Ice albedo feedback (positve feedback) Temperature increases More radiation is absorbed Ice melts Reveals darker surface

33. Climate Feedbacks Cloud feedbacks 1)Positive feedback Temperature increases More water vapour More outgoing longwave radiation is absorbed longwave radiation

34. Climate Feedbacks More incoming shortwave radiation is reflected shortwave radiation Cloud feedbacks 2)Negative feedback Temperature increases Temperature decreases More water vapour Less incoming shortwave radiation is absorbed

35. Climate Feedbacks Cloud feedbacks Overall Effect Unknown

36. Impacts of Global Warming • Amplified warming at high latitudes • Amplified warming in N. Hemisphere • Amplified warming over land • Increased winter precip. at mid-high latitudes • Increased likelihood of summer drought • Increased likelihood of extreme events • Retreat of glaciers and sea ice

37. Impacts on Canada • Flooding and erosion in coastal areas • Forests at risk from pests and drought • Environmental changes may harm plant and animal life • Decrease in quality of drinking water • More severe and frequent extreme weather • Changes to fishery habitats and populations • Possible benefit to agriculture industry

38. Glaciers Melting Wedgemont Glacier, Whistler BC

39. 20 glacier length records from different parts of the world Fig 2.18 (IPCC Report 2001) Glacier locations

40. Sea level rise 1910-1990 (IPCC Report 2001)

41. Freezing Point Warming of the Oceans As water heats it expands Thermal expansion

42. If Greenhouse gas concentrations were stabilized, sea level would nonetheless continue to rise for hundreds of years! (after 500 years, sea level rise from thermal expansion may have reached only half of its eventual level)

43. 21% of the world’s population live within 30 km of a shoreline Large coastal cities and agglomerations at the start of the 21st century (8 million people and above)

44. The Kyoto Protocol The Kyoto Protocol was adopted in Kyoto, Japan, on 11 December 1997 under theUnited Nations Framework Convention on Climate Change. The goal of the Kyoto Protocol is to cut the total greenhouse-gas emissions by at least 5% from 1990 levels in the commitment period 2008-2012

45. The Kyoto Protocol For Canada Cut emissions to 6% less than 1990 emissions Kyoto will now be legal

46. Global mean temperature Global mean sea level The Policy Action Warming (°C) Sea Level Rise (cm) 50.0 2.08 • We all do nothing: 48.5 2.00 • We all meet Kyoto targets but do no more: 45.5 1.80 • We all meet Kyoto targets and meet a 1%/year further reduction in emissions after 2010: The effect of Kyoto

47. Reductions Required for Stabilisation To stabilise the atmospheric concentration of CO2 at nearly 4 times preindustrial levels, emissions need to be cut by ~50% of 1990 levels globally

48. A Climate Success Story The 1987 Montreal Protocol and CFCs