If it seems like when it rains, it pours these days, it apparently is more often the case.
At least that is the conclusion of a new study by Environment New Jersey, which analyzed reams of state data from the National Climatic Data Center dating back to 1948 through 2011.
The new report found that heavy downpours that used to happen every 12 months on average in New Jersey now occur every nine months on average. Moreover, the biggest storms are getting bigger. The largest annual storms in New Jersey now produce 22 percent more precipitation, on average than they did 65 years ago, according to the study.
To Environment New Jersey, an advocacy group that has been pushing for more controls on greenhouse gas emissions in the state, those events are attributed to global climate change.
“We need to heed scientists’ warnings that this dangerous trend is linked to global warming, and do everything we can to cut carbon pollution today,” said Matt Elliott, clean energy advocate for the group. “Clearly, we have a problem on our hands.”
Elliott cited the series of severe storms which recently whacked parts of the state, including a storm at the end of June, which left more than 200,000 people without power in South Jersey, and hundreds of thousands more along other parts of the eastern seaboard.
The study argued scientists have concluded that the rise in frequency and severity of heavy rainstorms and snowstorms is linked to global warming. Warming increases evaporation and enables the atmosphere to hold more water, providing more fuel extreme rainstorms and heavy snowstorms.
Others were not so quick to link a series of unusual weather events directly to climate change.
David Robinson, state climatologist at Rutgers University, noted last August was the wettest August on record, dating back to records to 1885. Three of the five warmest Julys occurred in the last three Julys, he said. In July 2011, the temperature at Newark airport reached a record 108 degrees, Robinson said.
“You can’t take any one of those events and say they couldn’t have happened without global warming,” Robinson said.
Still, Robinson said he believes humans are causing a warming of Earth. “There may be a connection between the frequency of these storms and a warmer planet,” he said.
According to the U.S. Global Change Research program, the increase in heavy downpours is one of the clearest precipitation trends in the U.S. and linked the phenomenon to global warming, the report said.
The study also noted that nine of the 10 warmest years on record have occurred since 2000. “Without significant action to reducing global warming, the average temperature in the U.S. could rise by as much as an additional 10 degrees by the end of the century,” it predicted.
Nationally, the report found that storms with extreme precipitation increased in frequency by 30 percent across the contiguous United States from 1948 to 2011. In addition, the largest annual storms produced 10 percent more precipitation, on average. At the state level, 43 states show a significant trend toward more frequent storms with precipitation, while only one state, Oregon, shows a significant decline.
Elliot said the report demonstrates “we have a lot of work to do” at both the federal and state levels to reduce greenhouse gas emission.
“We applaud the Obama administration for their proposals to cut carbon pollution from vehicles and new power plants, and urge them to move forward with finalizing these critical initiatives this year,” he said. Elliott said New Jersey lawmakers should press efforts to convince Gov. Chris Christie to have the state join a 10-state regional effort to reduce greenhouse gas emissions. The governor pulled out of the program last December, calling it a tax on utility customers.
The study was based on data from 3,700 weather stations and a methodology developed by scientists at the National Climatic Data Center and the Illinoi Water Survey.