Global Warming In The News

Fort Worth and Dallas experienced a significant increase in the number of heavy storms that cause flooding and property damage over the past 60 years, according to a study released Tuesday that says global warming is at least partly to blame.

Environment Texas, an Austin-based advocacy group, analyzed data from more than 3,000 weather stations across the country. The group concluded that Dallas-Fort Worth is one of 55 metropolitan areas that have experienced a significant increase in extreme rain events since 1948. And the group predicts that the trend will accelerate as the climate warms, particularly in the Southwest.

"The evidence in the U.S. certainly supports that this is already happening," said Kevin Trenberth, head of the climate analysis section at the National Center for Atmospheric Research in Boulder, Colo. Trenberth was not involved in the Environment Texas study.

Some experts were more cautious.

"It is plausible, but I don't think [the study] is unequivocal evidence that global warming is the agent," said Robert Jackson, an expert on climate change at Duke University.

EXTREME RAIN

The study

Environment Texas found that the frequency of heavy rainstorms in the U.S. has increased between 1948 and 2006. They increased 42 percent in Dallas-Fort Worth, with most of the increase since 1970.

How it was done

The group analyzed daily precipitation data from 3,445 weather stations in the contiguous 48 states compiled by several government agencies.

Other research

A study led by Purdue University and released Monday concluded that global warming could increase weather conditions that spawn severe thunderstorms. That's consistent with findings by the Intergovernmental Panel on Climate Change, which has reported that global warming will increase the frequency of major rainstorms. Why? Warmer land and ocean surface temperatures send more water into the atmosphere through evaporation. Also, warmer air can hold more water vapor, so more rain falls.

Some doubts

Some climate experts say it's not certain that global warming is already causing extreme changes. That will happen, they say, in the coming decades. "I think it's very likely in this century we'll see more larger storms and that global warming will play a role," said Robert Jackson, an expert on climate change at Duke University.