1. The Tyndall Centre comprises nine UK research institutions. It is funded by three Research Councils - NERC, EPSRC and ESRC – and receives additional support from the DTI Climate Scenarios in Vulnerability, Impact and Adaptation Assessments: week 1 lessons AIACC Scenarios Training Course Norwich, 16-25 April 2002 Dr Mike Hulme

2. The Tyndall Centre comprises nine UK research institutions. It is funded by three Research Councils - NERC, EPSRC and ESRC – and receives additional support from the DTI Seven Lessons from Week 1 (1) conduct case studies of past climate ‘events’ to illustrate vulnerability (2) never forget the future in a fundamental sense is ‘unknown’ – extrapolatory, normative, exploratory scenarios (3) aim to integrate your scenario information – socio-economic, CO2, climate, sea-level (SRES narrative framework may help) (4) pay much attention to the quality of your observed data – case studies, model evaluation, reference climate to perturb (5) conduct sensitivity studies for your sector/model – you’ll learn a lot (6) if you can keep things simple, keep them simple – is sensitivity enough? will a GCM(s) suffice? (7) don’t take on an RCM if you’re not in the ‘game’ already and certainly not unless you have a ‘friend’

3. The Tyndall Centre comprises nine UK research institutions. It is funded by three Research Councils - NERC, EPSRC and ESRC – and receives additional support from the DTI Be as clear as you can about what you really need ….. not want you or others may want  How many scenarios do you need? Which uncertainties are you going to explore?  What non-climate information do you need in your scenario(s)?  Do you need local data for case studies/sites, or national/regional coverage?  What spatial resolution in your climate model output do you really need – 300k, 100k, 50k, 10k, 1k? Can you justify this choice?  Do you need changes in average climate, or in variability?  Do you need changes in daily weather, or just monthly totals?  What climate variables are essential for your study?

4. The Tyndall Centre comprises nine UK research institutions. It is funded by three Research Councils - NERC, EPSRC and ESRC – and receives additional support from the DTI So for example …. Case studies in vulnerability Sensitivity studies Scoping the extent of the problem – semi-qualitative work Model-based studies – model will dictate the requirements (e.g. crop or water or health model) Risk-based (threshold) studies Large-scale (regional) applications (gridded; 1k, 10k, 50k, etc.) versus site or catchment specific applications National, generic applications (UKCIP02) Who is your audience and how will you communicate with it?

5. The Tyndall Centre comprises nine UK research institutions. It is funded by three Research Councils - NERC, EPSRC and ESRC – and receives additional support from the DTI Why does creating climate scenarios give us so many problems? Problem 1. Models are not accurate …. … so we ‘cannot’ use data from climate models directly in environmental or social simulation models … add model changes to baseline – mean and variability … use a weather generator

6. The Tyndall Centre comprises nine UK research institutions. It is funded by three Research Councils - NERC, EPSRC and ESRC – and receives additional support from the DTI Why does creating climate scenarios give us so many problems? Problem 2. Different climate models give different results … … so we have difficulty knowing which climate model(s) to use … select on basis of validation, age, representativeness, accessibility – or use them all!

7. The Tyndall Centre comprises nine UK research institutions. It is funded by three Research Councils - NERC, EPSRC and ESRC – and receives additional support from the DTI Why does creating climate scenarios give us so many problems? Problem 3. It is expensive to run many (global/regional) climate model experiments for many future emissions …..… so we often have to make choices about which emissions scenarios from which we build our climate scenarios … may not matter much for 2020s, but will make a real difference by 2080s … pattern-scaling methods may help if we only have results from only one emissions scenario

8. The Tyndall Centre comprises nine UK research institutions. It is funded by three Research Councils - NERC, EPSRC and ESRC – and receives additional support from the DTI Why does creating climate scenarios give us so many problems? Problem 4. Climate models give us results at the ‘wrong’ spatial scale … … so we have to develop and apply one or more downscaling methods … these may be simple (interpolation) or complex (statistical downscaling, weather generators) … RCMs may get you so far, but probably not far enough

9. The Tyndall Centre comprises nine UK research institutions. It is funded by three Research Councils - NERC, EPSRC and ESRC – and receives additional support from the DTI Our problems would be much easier if …. Climate models were fully accurate Different climate models gave the same results One could run a GCM experiment over 200 simulated years in one day on a PC Climate models had a resolution of 1km But they don’t!