1. Global Warming ‘Political hype or reality?’ The Fernhurst Society - 5 April 2007 - John Clement

2. Global warming - questions  What is happening?  What are the reasons?  What is likely to happen from now on?  What can we do?

3. What’s happening? Observable warming Trending strongly above long-term averages since mid ‘70-s

4. NOT the Earth’s long-term climate cycle ‘000 years before present - + 5 - 0 - - 5 - - This cycle is driven by Earth’s orbit changes

5. What’s happening? Consistent observations Similar trending since mid ‘70-s by three independent measures

6. What are the reasons? The climate system

7. What are the reasons? Radiation balance  Energy coming into the Earth from the Sun — SOLAR radiation  Energy leaving the Earth to outer Space — INVISIBLE INFRARED radiation INFRARED radiation

8. Solar radiation at poles and equator Near the poles, the Sun’s rays are spread out over a wide area, so the heating is less intense Near the equator, the Sun’s rays are spread out over a smaller area, so the heating is more intense The Earth’s climate systems in the atmosphere and oceans transport heat between the equator and the poles - and produce the ‘weather’ SUN’S RAYS

9. Range of global temperatures

10. What are the reasons? Is it solar radiation?

11. Implied changes in global temperature (°C) What are the reasons? Solar radiation? 0.1 0.2 0 Solar radiation – has been stable for the last 50 years

12. What is the reason?  Energy coming into the Earth from the Sun — SOLAR radiation  Energy leaving the Earth to outer Space — INVISIBLE INFRARED radiation INFRARED radiation

13. What is the reason? The ‘greenhouse’ effect?

16. Greenhouse gas increases through Industrial Age  CO 2 – roughly constant at 280 ppm until 1800 – then rising rapidly to 380+ ppm today, and then rising rapidly to 380+ ppm today, and further yet. further yet.  Methane – 800 ppb until 1800, now 1,750 ppb. now 1,750 ppb.  Nitrous oxide 270ppb until 1800 – now 310 ppb  Lower atmosphere ozone increased around 30% over the same period.

18. Greenhouse gases Predicted warming effect over the next 100 years Methane 24% Carbon dioxide 63% Nitrous oxide 10% Others 3% CO2 is the major contributor

19. Volcanoes also affect the atmosphere

20. Volcanic aerosols in the atmosphere 543210543210 543210543210 Estimated cooling effect, Wm 1883 Krakatau 1980 Mt. St. Helens 1991 Mt. Pinatubo

21. What’s happening? Observable warming Trending strongly above long-term averages since mid ‘70-s Suspected effect of atmospheric particulates

22. Climate models - improving

23. Natural factors alone do not explain the pattern of global warming since industrialisation

24. CO 2 in the atmosphere – long term stability until industrialisation The Industrial Age

25. CO 2 from fossil fuels – rapid rise since 1950

26. Addition of man-made factors to models duplicates observations

27. Q. Global Warming? Change between 1750 and 2000 A. Man-made gases dominate

28. Global warming - questions  What is happening?  What are the reasons?  What is likely to happen from now on?  What can we do?

29. Global warming  What is happening?  What are the reasons?  What is likely to happen from now on?  What can we do?

30. What is likely to happen from now on?  Depends on what we do.  Slowing down GHG emissions, particularly carbon, will mitigate future temperature rises – but there is a lot of momentum already embedded in the climate system.  Adaptation will be needed for coming changes in – rainfall patterns - glaciers and sea-ice - sea-levels - land temperatures - food crop, forest and animal ranges - human impacts – livelihoods, wealth and health

31. Rainfall Glaciers and sea-ice Sea levels Land temperatures

32. Rainfall - changing

33. UK precipitation by 2080s

34. European summer rainfall outlook - 2080s

35. Rainfall Glaciers and sea-ice Sea levels Land temperatures

36. Glaciers – melting 16,700 in the world – 13,500 are in retreat

37. Gangotri glacier, Himalayas – a case study

38. Himalayan glaciers - critical

39. Himalayan glaciers feed 7 of Asia’s great rivers - The Ganges - The Indus - The Brahmaputra - The Salween - The Mekong - The Yangtze - The Yellow river Himalayan glaciers - critical 2.3 billion people

40. Rainfall Glaciers and Sea-ice Sea levels Land temperatures

41. Sea ice – also melting 1.3 million km 2 Arctic ice lost since mid-70s

42. Arctic sea-ice, maybe disappearing by 2080s

43. West Antarctic and Greenland ice sheets = 6m sea level rise = 7m sea level rise 1,000 years to melt, but……..

44. Oceans - The north Atlantic Conveyor

45. Hypothetical collapse in ocean currents

46. Best forecasts of Atlantic circulation – its OK!

47. Rainfall Glaciers and sea-ice Sea levels Land temperatures

48. Components of sea level rise

49. Long-term momentum of sea-level rises

50. IPCC estimates of global mean sea-level rise

51. North Sea storm surges by 2080

52. Rainfall Glaciers and sea-ice Sea levels Land temperatures

53. European hot summers – human activity has roughly doubled the chances

54. European summer temperatures rising 2003

55. Global warming - questions  What is happening?  What are the reasons?  What is likely to happen from now on?  What can we do?

56. What can we do?  Avoid unnecessary carbon  Be prudent with necessary carbon  Offset and seuester as much carbon as possible  Adapt

57. CO 2 emissions reductions - the only route to stable concentrations. CO 2 concentration (ppm) 750 650 550 450 350 250 1990 2010 2030 2050 2070 2090 Year ◄ Pre-industrial concentration Constant 1990 emissions Business as usual 50% 1990 emissions

58. No getting away from it – future warming

59. What can we do?  Avoid unnecessary carbon  Be prudent with necessary carbon  Offset and sequester as much carbon as possible  Adapt Cross fingers for approx. 200 years!

60. The End The Fernhurst Society - 5 April 2007 - A presentation by John Clement