The tenth IMSC, Beijing, China, 2007 - International Meetings on ...
The tenth IMSC, Beijing, China, 2007 - International Meetings on ...
The tenth IMSC, Beijing, China, 2007 - International Meetings on ...
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Extending attributi<strong>on</strong> studies: postage stamps for the world<br />
Speaker: Dáithí St<strong>on</strong>e<br />
Dáithí St<strong>on</strong>e<br />
Tyndall Centre, Dept. of Physics, University of Oxford<br />
st<strong>on</strong>ed@atm.ox.ac.uk<br />
Studies of the detecti<strong>on</strong> and attributi<strong>on</strong> of climate change are progressing bey<strong>on</strong>d the<br />
questi<strong>on</strong> `Have we influenced the climate?' and starting to address the questi<strong>on</strong> `How does the<br />
current climate differ because of our influence?' <str<strong>on</strong>g>The</str<strong>on</strong>g> subtle but important difference between<br />
these two questi<strong>on</strong>s means that different assumpti<strong>on</strong>s are required when addressing them.<br />
Are these assumpti<strong>on</strong>s c<strong>on</strong>tradictory? This talk will discuss these questi<strong>on</strong>s through a<br />
comparis<strong>on</strong> of observed c<strong>on</strong>tinental surface temperature trends with those from a multi-model<br />
ensemble of historical simulati<strong>on</strong>s including <strong>on</strong>ly natural external forcings and an ensemble<br />
including both anthropogenic and natural forcings.<br />
C<strong>on</strong>sistency of observed winter precipitati<strong>on</strong> trends in northern Europe with regi<strong>on</strong>al climate<br />
change projecti<strong>on</strong>s<br />
Speaker: Hans v<strong>on</strong> Storch<br />
Hans v<strong>on</strong> Storch<br />
Institute for Coastal Research, GKSS<br />
hv<strong>on</strong>storch@web.de<br />
J<strong>on</strong>as Bhend<br />
Institute for Coastal Research, GKSS<br />
Often it is claimed that the recent changes in northern European climate are at least<br />
partly anthropogenic even though a human influence has not yet been successfully detected.<br />
Hence we investigate whether the recent changes are c<strong>on</strong>sistent with regi<strong>on</strong>al climate change<br />
projecti<strong>on</strong>s.<str<strong>on</strong>g>The</str<strong>on</strong>g>refore, trends in winter (DJF) mean precipitati<strong>on</strong> in northern Europe are<br />
compared to human induced changes as predicted by an ensemble of four regi<strong>on</strong>al climate<br />
model simulati<strong>on</strong>s.<br />
<str<strong>on</strong>g>The</str<strong>on</strong>g> patterns of recent trends and predicted changes match reas<strong>on</strong>ably well as indicated<br />
by pattern correlati<strong>on</strong> and the similarity is very likely not random. However, the model<br />
projecti<strong>on</strong>s severely underestimate the recent change in winter precipitati<strong>on</strong> by 50 to 80\%.<br />
That is, the signal-to-noise ratio of the anthropogenic precipitati<strong>on</strong> change is either rather low<br />
or the presently used simulati<strong>on</strong>s are significantly flawed in their ability to project changes into<br />
the future.<br />
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