Friday, July 13, 2012

Climate Change Attributions

Extreme Heat: The Odds Are Increasing, was published just before the American Meteorological Society (AMS) released their annual climate report this past week. 

The 2011 State of the Climate report is peer-reviewed and published annually as a special supplement to the Bulletin of the American Meteorological Society. The report is part of a suite of climate services NOAA provides government, business and community leaders so they can make informed decisions. It was edited by Jessica Blunden, Ph.D., and Deke Arndt of NOAA’s National Climatic Data Center. The full report can be viewed online. The report highlights are available online.

The map above shows where in the United States June 2012 temperatures were different from the 1981–2010 average. Shades of red indicate temperatures up to 8° Fahrenheit warmer than average, and shades of blue indicate temperatures up to 5° Fahrenheit cooler than average—the darker the color, the larger the temperature difference.  Image Credit: NOAA Climate.

Additionally, for the first time a complementary article was published by the AMS examining the linkages between climate change and extreme events of 2011. The paper looked at six global extreme weather and climate events from last year.

The paper, Explaining Extreme Events of 2011 from a Climate Perspective, was produced by NOAA and UK Met Offices scientists as well as numerous colleagues around the world. It was edited by Thomas Peterson, NOAA’s National Climatic Data Center; Peter Stott, UK Met Office-Hadley Center; and Stephanie Herring, NOAA’s Office of Program Planning and Integration.  This study can also be found online.

It is interesting that the conclusions are similar to what I laid out in the previous post.  The odds were done in 2010 for Columbia, but were more recent for the study above.

Here are the key findings:
  • Determining the causes of extreme events remains difficult. While scientists cannot trace specific events to climate change with absolute certainty, new and continued research help scientists understand how the probability of extreme events change in response to global warming.
  • La Niña-related heat waves, like that experienced in Texas in 2011, are now 20 times more likely to occur during La Niña years today than La Niña years fifty years ago.
  • The UK experienced a very warm November 2011 and a very cold December 2010. In analyzing these two very different events, UK scientists uncovered interesting changes in the odds. Cold Decembers are now half as likely to occur now versus fifty years ago, whereas warm Novembers are now 62 times more likely.
  • Climate change cannot be shown to have played any role in the 2011 floods on the Chao Phraya River that flooded Bangkok, Thailand. Although the flooding was unprecedented, the amount of rain that fell in the river “catchment” area was not very unusual. Other factors, such as changes in reservoir policies and increased construction on the flood plain, were found most relevant in setting the scale of the disaster.
Note in the Thailand flooding that attribution was given more to reservoir policies and increased construction on the flood plain.  While this is not weather related it is still a human attribution.  Weather and climate issues aren’t the only issues that need to be examined.  Everything we do has consequences.

The evidence is increasing of the human contribution to extreme events.  The odds are increasing for all extreme events.

In addition, Peter Sinclair, of Climate Denial Crock of the Week, has put together another very interesting film.  I will end this post with the video: