Understanding Climate Risk

Science, policy and decision-making

Posts Tagged ‘climate shifts

Nothing grows in Texas

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The Sacred Cowboys sang nothing grows in Texas. Last summer it came true. The Texan drought of 2011 was hotter and drier than any of the great droughts of the 1930s. Is it possible to diagnose what role climate change may have played? State Climatologist for Texas John Nielsen-Gammon asked this question last year in a preliminary post on the drought.

He concluded there was a strong anthropogenic evidence for warming but little evidence for its influence on the extremely low rainfall. The following analysis was developed without seeing his summary and happily, they have much in common. The big difference is the explicit treatment of non-linear warming.

I applied the methods for analysing step changes and attributing regional warming developed for SE Australia to the Texan climate. Was it possible to estimate the relative contributions of global warming for a single season? The results were more successful than I had anticipated. Tmax was 86% more likely to be due to anthropogenic warming and Tmin 95%. The method is unorthodox, so may be controversial. Details over the fold.  Read the rest of this entry »

Written by Roger Jones

March 12, 2012 at 12:40 am

Climate shifts paper published

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The climate shifts paper on non-linear anthropogenic climate change in SE Australia with earlier descriptions here and herehas been published in the Journal of Geophysical Research. We had plans to make it open access  but must not have paid the invoice yet, so it’s behind a paywall here (pdf). If you can’t get access, get in touch with me via comment below or email (firstname.lastname at vu.edu.au) and I’ll send a reprint.

Following is an edit of the draft press release that should go out in the next week or so. The press release implies that this pretty much goes on everywhere – not just SE Australia. That’s what I believe from further work currently underway – the ocean runs the climate system and the atmosphere doesn’t warm quite the way people assume it does. The energy from greenhouse warming goes into the ocean first, then is re-emitted periodically into the atmosphere. The atmosphere doesn’t warm in situ (or not yet to any significant degree). It may later under increased radiative forcing, but at the moment the ocean is pretty much running the show. This pattern of non-linear change fits in with palaeoclimatic evidence from the region that I’ll get round to describing some time.

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