Dec 11, 2012

Global increase in record-breaking monthly-mean temperatures

Dim Coumou, Alexander Robinson, Stefan Rahmstorf
Climatic Change
  • Shows that, worldwide, the number of local record-breaking monthly temperature extremes is now on average five times larger than expected in a climate with no long-term warming
  • Says this implies that on average there is an 80 % chance that a new monthly heat record is due to climatic change
  • States that large regional differences exist in the number of observed records
  • Finds summertime records, which are associated with prolonged heat waves, increased by more than a factor of ten in some continental regions including parts of Europe, Africa, southern Asia and Amazonia
  • States that overall, these high record numbers are quantitatively consistent with those expected for the observed climatic warming trend with added stationary white noise
  • Finds that the observed records cluster both in space and in time
  • Finds that strong El Niño years see additional records superimposed on the expected long-term rise
  • Predicts that under a medium global warming scenario, by the 2040s the number of monthly heat records globally to be more than 12 times as high as in a climate with no long-term warming