Scientists Link Trend to Global Warming
Environment Maine Research and Policy Center
Portland, Maine – One month after heavy rains led to record flooding that devastated Brownville and surrounding towns, a new Environment Maine report released today shows that extreme rainstorms snowstorms are happening 74 percent more frequently in Maine since 1948.
“When it rains, it pours—especially in recent years as bigger storms have hit Maine more often,” said Ben Seel, Clean Energy Organizer for Environment Maine. “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 or snowstorms that used to happen once every 12 months on average in state now happen every 6.9 months. Moreover, the biggest storms are getting bigger. The largest annual storms in Maine now produce 23 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.
Seel pointed to the rainstorm that hit Brownville in late June as an illustration of what more extreme rainstorms could mean for the state. That rainstorm, which dumped more than six inches of rain on the area, led to an estimated $4 million in damages, including washed out roads and rail lines.
The new Environment Maine 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 Maine and New England include:
- Extreme rainstorms and snowstorms are becoming more frequent. Maine experienced a 74 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 6.9 months, on average.
- Storms with extreme precipitation increased in frequency by 85 percent in New England during the period studied. The New England 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 Maine increased by 23 percent from 1948 to 2011.
Environment Maine was joined by Congresswoman Chellie Pingree, State Senator Justin Alfond, John Jemison of the University of Maine Cooperative Extension, and Dr. Johan Erikson, professor of environmental science at St. Joseph’s College of Maine at a press event to release today’s report.
Seel 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.
John Jemison, a water quality expert who works with many Maine farmers noted that these changes are particularly tough for Maine’s farming community. “Some growers think the climate is changing and not for the better,” said Jemison. “We need to give growers profitable options that are productive but are also more protective of the soil and the environment in an era of less predictable weather and more extreme precipitation.” Extreme downpours can directly damage farm crops, or cause flooding that wipes out whole harvests.
“All you have to do is turn on the evening news and you can see the effects of climate change. In a lot of the country it’s the worst drought in generations, and here in New England it’s more frequent severe rainstorms and snowstorms. It’s time to stop ignoring the problem and start coming up with some solutions,” said Congresswoman Chellie Pingree.
“Like most people, students in my climate class initially associate ‘global warming’ with more hot, dry, sunny days. That is the case in some locations, but, as this report documents, most of the United States and New England in particular is experiencing more intense precipitation. And heavy storms are only likely to get more severe,” said Johan Erikson of St. Joseph’s College of Maine.
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 Maine 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, officials in the northeast states are considering ways to strengthen the Regional Greenhouse Gas Initiative (RGGI), the first-in-the-nation program to limit carbon pollution from the power sector and sell permits to pollute that has led to nearly $1 billion in investments in energy efficiency and clean energy solutions in the region.
“This is an issue of immediate concern and inaction is a costly choice. Fortunately, RGGI provides Maine with a commonsense way to reduce the carbon pollution that is fueling global warming and threatening our health and environment,” said Senator Justin Alfond.
“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 Seel. “Maine can build on the progress we have made reducing carbon pollution by strengthening the Regional Greenhouse Gas Initiative, which has been a key part of our state’s strategy to reduce pollution and shift to clean energy.”
Environment Maine is a statewide, citizen-based environmental advocacy organization working for clean air, clean water, and open spaces.