By Juliet Eilperin, Updated: Friday, November 18, 9:00 PM
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?”
The report says there is at least a 66 percent chance that climate extremes have changed as a result of greenhouse gas emissions caused by human activities, including coal-fired power plants and fuel burned through transportation. It notes that “economic losses from weather- and climate-related disasters are increasing,” though they can fluctuate from year to year. The overall economic and insured losses are greater in industrialized nations, while in poor countries extreme weather events cause more deaths and represent a greater proportion of the gross domestic product.
Connie Hedegaard, the European Commissioner for Climate Action, said in an interview Thursday that policymakers cannot afford to ignore the sort of scientific findings summarized in the new IPCC report. “The science is not getting more uncertain; it’s actually getting more and more certain,” she said. “It’s getting in line with what people intuitively feel.”
This year has already set a record in terms of billion-dollar disasters for the United States, according to the National Climatic Data Center, with at least 10 disasters so far approaching a total of $50 billion.