Oct 11, 2007

Attribution of observed surface humidity changes to human influence

Katharine M. Willett, Nathan P. Gillett, Philip D. Jones, Peter W. Thorne
  • Uses a new quality-controlled and homogenized gridded observational data set of surface humidity, with output from a coupled climate model, to identify and explore the causes of changes in surface specific humidity over the late twentieth century
  • Identifies a significant global-scale increase in surface specific humidity that is attributable mainly to human influence
  • Finds specific humidity has increased in response to rising temperatures, with relative humidity remaining approximately constant
  • States these changes may have important implications, because atmospheric humidity is a key variable in determining the geographical distribution and maximum intensity of precipitation, the potential maximum intensity of tropical cyclones, and human heat stress, and has important effects on the biosphere and surface hydrology