Laying the blame for extreme weather

PhysOrg.com: Floods, tornadoes, droughts and wildfires: They are all weather-related, but blaming the latest meteorological disaster on climate change has always been a tricky matter that climate scientists have been shy to do. After all, how can you point to a specific and local event, such as a tornado or dry spell, and say it is caused by something as long-term and huge as global warming?

"That's been the mantra of the community and I think it's wrong," said climate scientist Kevin Trenberth of the National Center for Atmospheric Research (NCAR) in Boulder, Colorado. Trenberth and other climate scientists will be giving presentations that connect extreme weather over the past decade to climate change at a session of The Geological Society of America meeting in Minneapolis on Tuesday, 11 October 2011.

The session, titled Extreme Climate and Weather Events: Past, Present, and Future, begins with Trenberth's presentation, "The Russian Heat Wave and Other Climate Extremes of 2010." He cautions, however, that the harsh weather certainly didn't stop with 2011 and they all can be traced to the place where global warming stores its heat, year after year: the oceans.

The sea surface temperatures near all the extreme flooding events of 2010 were at record levels, Trenberth explains. That includes the Caribbean, Gulf of Mexico, N. Atlantic and the Indian Ocean.

"All of the storms are being formed in an environment that is warmer and wetter than before," said Trenberth. "The main thing that has happened with climate change is that you have changed the environment."...

Sun glinting through clouds during the STS-96 mission from the Space Shuttle Discovery. From NASA