| 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 |