1. The Science of Climate Change Why We Believe It and What Might Happen Dave Stainforth, University of Exeter Tyndall Centre for Climate Change Research London School of Economics Environmental Change Institute, Oxford University.

2. Climate Change – The Basics Atmospheric Greenhouse Gas Levels are Increasing Source: IPCC Fourth Assessment Report (SPM)

3. Climate Change – The Basics Scenarios of Future Human Activity Note different scale! Source: IPCC Third Assessment Report In 2005 CO 2 concentrations were about 380ppm but greenhouse gas concentrations were about 430 ppme (ppm equivalent)

4. Climate Change – The Basics Global Temperatures and Sea Levels are Rising Source: IPCC Fourth Assessment Report (SPM)

5. Climate Change - Fundamentals Commitment to Further Warming  We are committed to further warming based on past emissions alone. Around 0.5°C - 1°C according to Wigley 2005 and Meehl, 2005.

6. Climate Change: Global Projections By 2020s we can expect global temperatures to be between 0.3°C and 1.3°C warmer than the 1990s. (Stott and Kettleborough, 2002) Source: IPCC Fourth Assessment Report (SPM)

7. "We need to treat climate change not as a long term threat to our environment, but as an immediate threat to our security and prosperity," John Ashton, UK Climate Ambassador at the Foreign Office 2006

8. Terminology – Mitigation and Adaptation  Mitigation: “A human intervention to reduce the sources or enhance the sinks of greenhouse gases.”  Adaptation: “Adjustment in natural or human systems in response to actual or expected climatic stimuli or their effects, which moderates harm or exploit beneficial opportunities”

9. Terminology – Mitigation and Adaptation Mitigation Adaptation

10. What is Climate Science? Maths: non-linear systems, chaos, game theory… Judd.pdf

11. What is Climate Science? Momentum equation Conservation of mass Conservation of energy Ideal gas law (equation of state of an “ideal” gas) Physics: atmosphere, oceans, clouds …

12. What is Climate Science?  Maths, physics, statistics, hydrology, geomorphology, ecology, agricultural science, economics, political science, international development …  Climate change science is a new science.  Climate change science is a mixture of many different disciplines; getting them to work together is itself a challenge.

13. Climate Change: Why we believe it’s a significant global problem  Basic physics:  Atmospheric GHGs increase surface temperatures. (The earth would be 30 o C colder if they didn’t.)  GHGs should increase surface temperatures. (Just based on their basic radiative properties.)  Observations:  Global mean temperatures are increasing.

14. Some Sceptic Arguments: news.bbc.co.uk/2/hi/science/nature/7081026.stm 1.Evidence that the earth's temperature is getting warmer is unclear. 2.If the average temperature was rising, it has now stopped. 3.The earth has been warmer in the recent past. 4.Computer models are not reliable. 5.The atmosphere is not behaving as models would predict. 6.Climate is mainly influenced by the sun. 7.A carbon dioxide rise has always come after a temperature increase not before. 8.Long-term data on hurricanes and arctic ice is too poor to assess trends. 9.Water vapour is the major greenhouse gas; co2 is relatively unimportant. 10.Problems such as hiv/aids and poverty are more pressing than climate change.

16. Some Sceptic Arguments: news.bbc.co.uk/2/hi/science/nature/7081026.stm 1.Evidence that the earth's temperature is getting warmer is unclear. 2.If the average temperature was rising, it has now stopped. 3.The earth has been warmer in the recent past. 4.Computer models are not reliable. 5.The atmosphere is not behaving as models would predict. 6.Climate is mainly influenced by the sun. 7.A carbon dioxide rise has always come after a temperature increase not before. 8.Long-term data on hurricanes and arctic ice is too poor to assess trends. 9.Water vapour is the major greenhouse gas; co2 is relatively unimportant. 10.Problems such as hiv/aids and poverty are more pressing than climate change.

17. Feedbacks  Feedbacks: water vapour, clouds, land surface, ice sheets, methane hydrates …  The sceptic view: Negative feedbacks in the climate system will counteract any potential warming due to increased atmospheric GHGs. (e.g. Richard Lindzen’s Iris effect)

18. What happens next.

19. UK Climate Impacts Programme Scenarios “The UKCIPnext climate change scenarios will be presented … as probability distributions.” They will be available for 25km grid boxes.“Model outputs will include changes in temperature, precipitation, snowfall, wind speed, humidity, cloud cover, solar radiation, air pressure and soil moisture content.” Source : UKCIPnext Consultation

20. Climateprediction.net, distributions and ranges Mediterranean BasinNorthern Europe Winter Summer Annual

21. Exploring Possibilities

22. Going Forward  We all need to start debating how to respond to climate change – not whether it is happening.  To get the best out of the science, industry and academia need to work together.

23. Climate change is happening, but is it man-made? The Royal Society has a website which answers this.