New Report: Extreme Rainstorms and Snowstorms Up 33 Percent in NJ

Scientists Link Trend to Global Warming

Environment New Jersey Research and Policy Center

Trenton—Just days a series of severe storms ripped through Central Jersey, leading to severe rains and flooding that devastated the town of Freehold, a new Environment New Jersey report confirms that extreme rainstorms and snowstorms are happening 33 percent more frequently in New Jersey since 1948.  The Central Jersey storm followed a June 29th storm that brought high winds and rain to Southern Jersey, now considered one of the most destructive and severe thunderstorms in the region’s history.  206,000 people in Atlantic, Cumberland, and Salem counties lost power following the June 29th storm.  

“As the old saying goes, when it rains, it pours—especially in recent years as bigger storms have hit New Jersey more often,” said Matt Elliott, Clean Energy Advocate for Environment New Jersey.  “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.”  

Based on an analysis of state data from the National Climatic Data Center, the new report found that heavy downpours that used to happen once every 12 months on average in New Jersey now happen 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.  

Scientists have concluded that the rise in the 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 for extreme rainstorms and heavy snowstorms.  

Elliott pointed to the recent rainstorms that hit Freehold and other parts of Monmouth County on July 28th, 2012 as an illustration of what more extreme rainstorms and snowstorms could mean for the state.  That brought heavy rain and winds, causing power outages for thousands in Central Jersey.

The new Environment New Jersey Research and Policy Center report, When It Rains, It Pours: Global Warming and the Increase in Extreme Precipitation from 1948 to 2011, examines trends in the frequency of and the total amount of precipitation produced by extreme rain and snow storms across the contiguous United States from 1948 to 2011.  Using data from 3,700 weather stations and a methodology originally developed by scientists at the National Climatic Data Center and the Illinois State Water Survey, the report identifies storms with the greatest 24-hour precipitation totals at each weather station, and analyzes when those storms occurred. The report also examines trends in the amount of precipitation produced by the largest annual storm at each weather station.

Nationally, the report found that storms with extreme precipitation increased in frequency by 30 percent across the contiguous United States from 1948 to 2011. Moreover, 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 extreme precipitation, while only one state (Oregon) shows a significant decline.  

Key findings for New Jersey and the region include:
•    Extreme rainstorms and snowstorms are becoming more frequent. New Jersey experienced a 33 percent increase in the frequency of extreme rainstorms and snowstorms from 1948 to 2011.  In other words, heavy downpours or snowstorms that happened once every 12 months on average in 1948 now happen every 9 on average.
•    Storms with extreme precipitation increased in frequency by 85 percent in the Northeast region during the period studied.  The region ranks 1st nationwide for the largest increase in the frequency of storms with heavy precipitation.
•    The biggest rainstorms and snowstorms are getting bigger.  The amount of precipitation released by the largest annual storms in New Jersey increased by 22 percent from 1948 to 2011.

Elliott was careful to note that an increase in the frequency and severity of extreme rainstorms does not mean more water will be available for human use. Hotter temperatures fuel extreme rainstorms by increasing rates of evaporation. At the same time, however, that evaporation increases soil dryness. Moreover, scientists expect that, as global warming intensifies, longer periods with relatively little precipitation will tend to mark the periods between heavy rainstorms. As a result, droughts are likely to become more frequent and severe in some regions of the United States. Currently, more than half of the lower United States is suffering through prolonged drought, aggravated by the fact that the last six months have been the hottest January-June period on record.

According to the most recent science, the United States must reduce its total global warming emissions by at least 35 percent below 2005 levels by 2020 and by at least 85 percent by 2050 in order to prevent the most devastating consequences of global warming.  Environment New Jersey highlighted two proposals from the Obama administration—carbon pollution and fuel efficiency standards for cars and light trucks through model year 2025, and the first ever carbon pollution standards for new power plants—as critical steps toward meeting these pollution reduction targets.  

At the state level, New Jersey was, until December 2011, part of the Regional Greenhouse Gas Initiative (RGGI), the first-in-the-nation cap on carbon pollution from the power sector that sells permits for carbon emissions and has led to nearly $1 billion in investments in energy efficiency and clean energy solutions in the region.  Governor Christie has vetoed legislation to keep New Jersey in the program, eliminating one of New Jersey’s best tools to cut global warming pollution and fund clean energy projects.

“How serious this problem gets is largely within our control – but only if we act boldly to reduce the pollution that fuels global warming,” said Elliott.  “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.  Here in New Jersey, we can and should be doing more.  We will continue to urge Governor Christie and the State Legislature to rejoin RGGI and work with neighboring states to strengthen the program.  RGGI has cut pollution in New Jersey, reduced energy costs, created jobs, and supported clean energy.  Given the size of the problems before us, we need to continue our participation in this important program. “


Environment New Jersey Research and Policy Center is a statewide, environmental advocacy and education organization