Some issues in detecting climate change induced by greenhouse gases using general circulation models

Santer shows that the magnitude of model uncertainties affect both the predictions of how climate might change in response to changes in greenhouse gases, and the estimates of the decadal- to century-time scale natural variability (the "noise') of the climate system. Santer concludes that the only way to detect a climate change signal and attribute it convincingly to changes in greenhouse gases is by reducing the scientific uncertainties associated with the use of models to define the greenhouse gas signal and natural variability. He notes, however, that such uncertainty does not relieve policy makers of the responsibility of taking reasonable precautions. -from Editors