New Paper Contradicts IPCC Assumptions About Precipitation

  • Date: 27/11/12
  • The Hockey Schtick
The IPCC claims that a warming climate causes an increased variability of precipitation and that wet areas will become wetter and dry areas drier. However, a new paper published in Geophysical Research Letters finds on the basis of global observations from 1940-2009 that the opposite was true: precipitation variability decreased, there was no significant change in global average precipitation, and that dry areas became wetter and wet areas drier. 
According to the authors,

“We report a near-zero temporal trend in global mean Precipitation. Unexpectedly we found a reduction in global land Precipitation variance over space and time that was due to a redistribution, where, on average, the dry became wetter while wet became drier.”

Once again, observations demonstrate that the predictions of IPCC computer models fail to reflect the real world. The paper also adds to many others contradicting alarmist claims that global warming leads to more extreme weather.

Related: New paper finds models have it wrong again & predict excessive droughts

GEOPHYSICAL RESEARCH LETTERS, VOL. 39, L19402, 6 PP., 2012
doi:10.1029/2012GL053369
Key Points

  • We report a reduction in Precipitation variability and explain how that arose
  • The reason of the reduction of Precipitation variability is dry got wetter and wet got drier
  • A new detection method is proposed to confirm the conclusion
Fubao Sun, Research School of Biology, Australian National University, Canberra, ACT, Australia
Australian Research Council Centre of Excellence for Climate System Science, Sydney, New South Wales, Australia
Michael L. Roderick, Research School of Biology, Australian National University, Canberra, ACT, Australia; Australian Research Council Centre of Excellence for Climate System Science, Sydney, New South Wales, Australia; Research School of Earth Sciences, Australian National University, Canberra, ACT, Australia
Graham D. Farquhar, Research School of Biology, Australian National University, Canberra, ACT, Australia; Australian Research Council Centre of Excellence for Climate System Science, Sydney, New South Wales, Australia
In our warming climate there is a general expectation that the variability of precipitation (P) will increase at daily, monthly and inter-annual timescales. Here we analyse observations of monthly P (1940–2009) over the global land surface using a new theoretical framework that can distinguish changes in global P variance between space and time. We report a near-zero temporal trend in global mean Precipitation. Unexpectedly we found a reduction in global land Precipitation variance over space and time that was due to a redistribution, where, on average, the dry became wetter while wet became drier. Changes in the P variance were not related to variations in temperature. Instead, the largest changes in P variance were generally found in regions having the largest aerosol emissions. Our results combined with recent modelling studies lead us to speculate that aerosol loading has played a key role in changing the variability of P.

The Hockey Schtick, 26 November 2012