Operational attribution |
Why should we develop operational attribution? |
How can we answer the question ÒIs climate change to blame for this flood?Ó |
Making sense of the question |
The European heat-wave of 2003 |
Modelling Southern European area-averaged June-July-August summer temperatures |
How we attribute different contributions to an observed change in expected temperatures |
An example: attribution of hemispheric temperature changes with HadCM3 |
An example: attribution of hemispheric temperature changes with GFDL |
An example: attribution of hemispheric temperature changes with PCM |
External contributions to European summer temperatures, relative to pre-industrial |
Inferring external contributions to risk from external contributions to expected temperatures |
Changing risks of European
heatwaves (Stott et al, 2004) |
Anthropogenic contribution to the risk of the 2003 heat-wave |
Conclusions of Stott et al, 2004, study of the 2003 European heat-wave |
Autumn 2000 floods in the UK |
A template for operational
attribution (Pall et al, 2007) |
What, in climate research, is a relatively high-resolution model |
Patterns of SST signal removed: 1990s seasonal surface temperatures relative to control |
Large ensembles required, so we use distributed computing: http://attribution.cpdn.org |
Autumn 2000 as observed
(ERA-40 reanalysis)É Éand in one of the wetter members of our ensemble. |
Return-times versus total Sept-Nov precipitation in the ÒAutumn 2000Ó ensemble |
Return-times after removing estimated signal of greenhouse warming |
Return-times after removing estimated signal of greenhouse warming |
Contribution of greenhouse warming to risk of Autumn 2000 3-month precipitation anomalies |
Implications of Pall et al study |
Changing drought risk in Tripoli due to greenhouse gas increase 1900-2000 |
Link to work on attribution of trends in African rainfall (Hoerling et al, 2007) |
Impact of Indian Ocean warming on Southern African rainfall |