Aug 27, 2002

Estimation of natural and anthropogenic contributions to twentieth century temperature change

Simon F. B. Tett, Gareth S. Jones, Peter A. Stott, David C. Hill, John F. B. Mitchell, Myles R. Allen, William J. Ingram, Tim C. Johns, Colin E. Johnson, Andy Jones, David L. Roberts, David M. H. Sexton, Margaret J. Woodage
Journal of Geophysical Research: Atmospheres
  • Estimates the linear trend in global mean near‐surface temperature from well‐mixed greenhouse gases to be 0.9 ± 0.24 K/century, offset by cooling from other anthropogenic forcings of 0.4 ± 0.26 K/century, giving a total anthropogenic warming trend of 0.5 ± 0.15 K/century
  • The analysis suggests that the early twentieth century warming can best be explained by a combination of warming due to increases in greenhouse gases and natural forcing, some cooling due to other anthropogenic forcings, and a substantial, but not implausible, contribution from internal variability
  • Finds, in the second half of the century, that the warming is largely caused by changes in greenhouse gases, with changes in sulphates and, perhaps, volcanic aerosol offsetting approximately one third of the warming
  • Concludes that warming in the troposphere, since the 1960s, is probably mainly due to anthropogenic forcings, with a negligible contribution from natural forcings