Monday, June 25, 2012

New paper corroborates that water vapor is a negative feedback

A new paper published in Atmospheric Chemistry and Physics finds that semi-arid regions have warmed more than than the overall land average over the period 1901-2009. The paper indirectly confirms research conducted by physicist Clive Best finding that feedback from water vapor is negative.
[Clive Best] "the IPCC argues that  feedbacks from increased water evaporation will lead to enhanced warming. This is not observed in those regions most effected by water vapour. In fact the opposite seems to be the case implying negative feedback."
Atmos. Chem. Phys., 12, 5391-5398, 2012

Enhanced cold-season warming in semi-arid regions
J. Huang, X. Guan, and F. Ji
Key Laboratory for Semi-Arid Climate Change of the Ministry of Education, College of Atmospheric Sciences, Lanzhou University, Lanzhou, 730000, China
Abstract. This study examined surface air temperature trends over global land from 1901–2009. It is found that the warming trend was particularly enhanced, in the boreal cold season (November to March) over semi-arid regions (with precipitation of 200–600 mm yr−1) showing a temperature increase of 1.53 °C as compared to the global annual mean temperature increase of 1.13 °C over land. In mid-latitude semi-arid areas of Europe, Asia, and North America, temperatures in the cold season increased by 1.41, 2.42, and 1.5 °C, respectively. The semi-arid regions contribute 44.46% to global annual-mean land-surface temperature trend. The mid-latitude semi-arid regions in the Northern Hemisphere contribute by 27.0% of the total, with the mid-latitude semi-arid areas in Europe, Asia, and North America accounting for 6.29%, 13.81%, and 6.85%, respectively. Such enhanced semi-arid warming (ESAW) imply drier and warmer trend of these regions.
Final Revised Paper (PDF, 1422 KB)   Discussion Paper (ACPD)   

No comments:

Post a Comment