The climate has warmed in Maine and Vermont more than in every other state in the past 30 years, a shift that scientists say is evident in the species of birds and fish that are moving into or out of northern New England.
The six New England states, along with three of their neighbors in the Northeast, accounted for nine of the 10 states that have had the largest increase in annual average temperature since 1984, according to an Associated Press analysis of temperature records from the federal government’s National Climatic Data Center.
The average annual temperature in both Maine and Vermont rose by 2.5 degrees from 1984 to 2013, roughly double the average warming nationwide. Northern Maine had an even larger spike, 2.64 degrees, the AP reported Wednesday.
The harsh winter that just loosened its grip on New England notwithstanding, winter temperatures are rising faster than summer temperatures in Maine and other northern climes. That is opposite the national trend.
Sean Birkel, a research assistant professor at the University of Maine’s Climate Change Institute, said part of Maine’s winter warming trend is attributable to the fact that Arctic sea ice is melting as that region warms. As sea ice melts, sunlight is absorbed by the darker ocean, further heating the air.
“As the Arctic warms, Maine and the North will warm because that is where the airflow is coming from” in winter, Birkel said.
He noted that examining a 30-year batch of records for climactic shifts would not fully take into account natural patterns that can extend for longer periods, such as a 60-year pattern affecting water temperatures in the North Atlantic. Complicating things further, temperatures are rising worldwide because of greenhouse gases being pumped into the atmosphere from human activities.
CHANGES IN PRESENCE OF WILDLIFE
Bird-watchers, fishermen and farmers are already noticing a difference in Maine.
Jeff Wells, an internationally known ornithologist who lives in Maine and serves as science and policy director for the Boreal Songbird Initiative, said he can remember driving from Augusta to the Falmouth area 25 years ago to see a Carolina wren.
“Everybody was driving down because they were so rare,” said Wells, author of the “Birder’s Conservation Handbook: 100 North American Birds at Risk.”
“Now they are nesting at least throughout the southern third of the state,” he said.
Red-bellied woodpeckers, tufted titmouse and turkey vultures also have moved into Maine from southern states. And native species such as the Bicknell’s thrush – which relies on a specific type of alpine forest that’s becoming less prevalent in Maine – Atlantic puffins and saltmarsh sharp-tailed sparrows are finding it harder to survive in the warmer temperatures, Wells said.
The AP analysis of air temperatures – and its finding of regional differences – is consistent with what oceanographers are seeing in the Gulf of Maine.
Over the past decade, water temperatures in the Gulf of Maine have warmed by roughly 0.5 degrees per year – “faster than pretty much everywhere else in the global ocean,” said Andrew Pershing, chief scientific officer at the Gulf of Maine Research Institute in Portland.
As a result, southern species such as black sea bass, squid and butterfish have moved into the gulf, while historically local species have shifted north or dwindled in numbers. The center of Maine’s lobster fishery has also shifted north, a move that many fishermen and scientists attribute to warming water temperatures.
“We have seen some real changes in the Gulf of Maine ecosystem,” Pershing said. “And it has been surprising to some of us how quickly things could change.”
ONLY ONE LOWER-48 STATE IS COOLER
Not all of the changes caused by rising temperatures are bad. A recent federal report on the regional effects of long-term climate change noted that warmer summers will likely draw more tourists to Maine’s beaches, lengthen growing seasons for farmers and provide new opportunities for adaptable fishermen.
The AP analysis shows that the country is warming fastest in the Northeast and the Southwest.
To determine what parts of the country have warmed the most, the AP analyzed National Climatic Data Center temperature trends in the lower 48 states, 192 cities and 344 smaller regions within the states. Climate scientists suggested 1984 as a starting date because 30 years is a commonly used period.
All but one of the lower 48 states have warmed since 1984, the AP found. North Dakota, the lone outlier, had cooled slightly.
Ten states – Maine, Vermont, New Jersey, Massachusetts, New Hampshire, Rhode Island, Delaware, New Mexico, Connecticut and New York – have gotten at least 2 degrees warmer in the past 30 years, the news service reported.
The contiguous United States’ annual average temperature has warmed by 1.2 degrees since 1984, with summers getting 1.6 degrees hotter. Some areas have gotten hotter than others because of atmospheric factors and randomness, climate scientists say.
“In the United States, it isn’t warming equally,” said Kelly Redmond, climatologist at the Western Regional Climate Center in Reno, Nevada. “Be careful about extrapolating from your own backyard to the globe.”
For example, while people in the East and Midwest were complaining about a cold winter this year, Nevada and neighboring California were having some of their warmest winter months ever.
Kevin Miller can be contacted at 791-6312 or at: