http://www.realclimate.org/index.php?p=230#more-230
realclimate.org wrote:In summary, it does not appear possible to say that this single event is attributable to climate change as the noise in the rainfall statistics is large. Here the question has been on attributing the drought to an enhanced greenhouse effect, as opposed to the study of the Euopean heat wave, where the link between increased risk of similar extremely hot 2003 European summers and a global warming was estimated; Stott et al, 2004 acknowledge that 'It is an illposed question whether the 2003 heatwave was caused, in a simple deterministic sense, by a modification of the external influences on climate ' . Past studies have shown that rainfall anomalies over the Amazon basin can be associated with SST changes in the Atlantic, but that these SSTs can only account for part of the picture. Hence, the record drought itself likely cannot be solely attributed to the specific 2005 SSTs in the Carribean/Atlantic basin, although high SST nevertheless are likely to have some effect on the rainfall statistics. It may be that better data or more detailed modelling could change this picture though... but that's a little beyond the scope of a blog posting.