Droughts, floods to be more common

The Columbia Daily Tribune (Missouri) via the Washington Post: Climate change will make the drought and flooding events that have battered the United States and other countries in 2011 more frequent in years to come, forcing nations to rethink the way they cope with disasters, according to a new report the U.N. Intergovernmental Panel on Climate Change issued last week.

The report, the culmination of a two-year process involving 100 scientists and policy experts, suggests researchers are far more confident about the prospect of more intense heat waves and heavy downpours than they are about how global warming is affecting hurricanes and tornadoes. But the new analysis also speaks to a broader trend: The world is facing a new reality of more extreme weather, and policymakers and businesses alike are beginning to adjust.

Gerald Meehl, a senior scientist at the National Center for Atmospheric Research and one of the report’s reviewers, said it highlights why climate change means more than just a gradual rise in the global temperature reading.

“The fact is a small change in average temperature can have a big impact on extremes,” Meehl said in an interview. “It’s pretty straightforward: As average temperatures go up, it’s fairly obvious that heat extremes go up and” the number of “low extremes go down.”

Meehl co-authored a 2009 study showing that during the last decade the number of record highs in the United States outnumbered the record lows by an average of 2-to-1; historically, the two have been roughly even. Two Australian researchers last year found a similar trend between 1997 and 2009.

Christopher Field, one of the leaders of the IPCC, said members of the climate panel teamed up with disaster experts around the world to answer three central questions: “What do we know about the changes in climate extremes that have already occurred and are expected to occur; what are the consequences of these changes; and what can you do about it?”...