1. What is the point of this session? To use the UK’s experience to give ideas about creating and using climate change scenarios in other countries and situations Not a talk on climate modelling! An overview of who, how, what and why Discussion of how these experiences apply to your own needs

2. The next hour and a half….. What are climate change scenarios and how have they featured in the UK? How have the “UKCIP02” scenarios been created? Who are the major players? How have we dealt with uncertainties? Potential applications of the UKCIP02 scenarios How can the scenarios be improved? Lessons for the future Discussion

3. What are scenarios? A scenario is: “a coherent, internally consistent and plausible description of a possible future state of the world” (Parry and Carter, 1998) l Not a forecast or a prediction l A series of pictures of what the world could look like in the future

4. Climate change scenarios Socio-economic futures (eg. population, economy, carbon intensity) - affects how GHG may change Climate modelling Result: integrated scenarios - more sophisticated than pure climate modelling

5. A history of UK Climate Change scenarios Climate Change Impacts Review Group of the DoE (CCIRG) 1991, 1996 Presented a range of highly artificial global- scale scenarios (CO 2 doubling) Tended to present a ‘best guess’ based on 1980s Met Office UKTR model and HadCM1

6. The 1998 UKCIP scenarios 1997: UK Climate Impacts Programme (UKCIP) 1998: Climatic Research Unit, Hadley Centre created UKCIP98 scenarios Wider range of variables and time-scales than CCIRG Range of four scenarios based on IS92a/IS92d HadCM2 model

7. How have the UKCIP02 scenarios been created?

8. UKCIP02 Climate Change Scenarios Mike Hulme Xianfu Lu John Turnpenny Tim Mitchell Geoff Jenkins Richard Jones Jason Lowe James Murphy David Hassell Penny Boorman Ruth McDonald Steven Hill

9. UKCIP02 Climate Change Scenarios Funded by: For:

10. The UKCIP02 Scenarios To be launched April 2002 Revised scenarios using developments over past three years Explicitly linked to four socio-economic scenarios produced by IPCC Informed by the Third IPCC Climate Change Assessment Report

11. Uses more sophisticated HadCM3 and regional HadRM3 models (more greenhouse gas species, improved ocean and vegetation models) Much more detailed regional information (104 vs. 4 grid boxes) 5 km observed data set Responses to users: much more on extremes; rapid climate change; Gulf Stream; uncertainty

12. The SRES Scenarios

13. Global carbon emissions - four IPCC scenarios (2000 - 2100)

14. Carbon dioxide concentrations: IPCC scenarios

15. The four UKCIP02 scenarios High EmissionsA1FI Medium-High EmissionsA2 Medium-Low EmissionsB2 Low EmissionsB1 as inputs to Hadley Centre’s HadCM3 model (effective sensitivity 3.0 deg C)

16. Global temperature (2000 - 2100)

17. The Hadley Centre Global Climate Model (HadCM3)

18. Hadley Centre Regional Climate Model (HadRM3) 50 km grid

19. What are UKCIP02’s defining characteristics? It was GENERIC rather than for a SPECIFIC impacts project The centre of a policy network of groups with different aims Scenario range examined emissions uncertainty rather than uncertainty in the model

20. What do the key players represent? DEFRA - funder; government policy; international obligations; public perception UKCIP - scenario users (scientists, policymakers, impact assessments) Hadley - rigorous science basis of climate modelling Tyndall - leading the analysis and writing; coordinating report production

21. The results UKCIP02 had to balance needs of all the organisations Ease of communication vs. rigorous science vs. usefulness to impacts community Example - pattern-scaling

22. Pattern-scaling Only A2 emissions, 2071-2100 means were modelled Other time periods and emissions scenarios were produced by ‘scaling’ the model output patterns Scientifically less than rigorous But needed by the users (eg 2020s, 2050s)

23. Interaction with other groups Hadley Centre modellers - storm surges/ocean modelling Land movement (Durham) Sea level (POL)

24. What will happen to sea level?

25. Sea level change: Four IPCC scenarios

26. Components of sea-level rise in 21st century

27. Commitment to sea-level rise: 600 + years

28. UK land movement (mm/yr) [Source: Ian Shennan]

29. How have we dealt with uncertainties?

30. What uncertainties are there? Emissions - how will society change? We chose to explicitly include these in the range of scenarios Scientific - how do different models represent the environment? We have assessed the main scientific uncertainties and provided guidance on how to incorporate these

31. UK temperature and precipitation (2080s) comparison of models

32. Winter temperature change with C-cycle (2080s, Medium-High Emissions)

33. Summer temperature change with C-cycle (2080s, Medium-High Emissions)

34. Methane concentrations - with and without climate change feedbacks (A2 Emissions)

35. Ozone concentrations - with and without climate change feedbacks (A2 Emissions)

36. Pattern-scaling Scientifically acceptable to scale HadRM3 patterns with other models’ global temperatures? We decided not. Acceptable comparison between model and pattern-scaled results? Yes.

37. HadRM2 vs. HadRM3 Mean temperature change

38. HadRM2 vs. HadRM3 Precipitation change

39. Daily maximum temperature: HadRM3 (dotted) vs. observations (solid)

40. Potential applications of the UKCIP02 scenarios

41. Impacts, Adaptation, Vulnerability Informing Mitigation Policy Education and communication

43. Lessons for the future

44. Questions for discussion Who are your scenarios for? Who is funding them? How will they link climate and social science? Who is the most important player? How might the different powers interact? How will you communicate them to relevant groups and to the public? Are they ‘user-friendly’? Which government department is responsible, if any?