The Northeast Is the Fastest-Warming Region in the Lower 48

Boston is wicked cold. Most of Florida’s snowbirds are native to New York, and hurricane-force blizzards are called nor’easters. To put it another way, in a game of word association with warm, the northeastern United States doesn’t exactly top the list. But when it comes to warming from climate change, the top of the list is just where the Northeast sits.

The Northeast is the fastest-warming region in the contiguous United States, according to a recent study—and it’s heating up at a rate 50 percent faster than the global average.

Climate change negotiations, like the 2015 Paris Agreement, revolve around this global average temperature. But here’s the thing about averages: By definition, they represent a set of numbers that includes both larger and smaller values. In the context of global warming, that means some regions of the planet are warming faster and others more slowly. And while the global average is useful from the standpoint of international collaboration, basing a particular region’s strategy for climate resilience on it is a bit like buying your suit based on the global average body weight—there’s a very good chance it won’t be tailored correctly. Only in this case, the error could mean the difference between life and death.

Knowing all this, Ambarish Karmalkar and Raymond Bradley, researchers at the Northeast Climate Science Center (NECSC), decided to get a clearer picture of regional warming rates across the Lower 48. The 200 or so countries that came to Paris in 2015 for the United Nations Climate Change Conference agreed to limit long-term warming to 1.5 degrees Celsius—after vulnerable Pacific island nations talked them down from the long-championed 2-degree target. But Karmalkar and Bradley suspected that many states may cross those thresholds sooner than the planet as a whole.

They had good reason to think so. Previous studies have shown that the Northern Hemisphere is warming significantly faster than the Southern Hemisphere, largely because it has more landmass. Water takes much longer to heat than land does (think of how long it takes to boil a pot of water compared with how long it takes to burn your hand), and the Southern Hemisphere is, well, swimming in it.

The two climate scientists worked with the same set of models used by the Intergovernmental Panel on Climate Change, comparing future scenarios depending on how aggressively the world chooses to respond to the climate crisis. They looked at what will be happening stateside as the world approaches 2 degrees and 1.5 degrees of warming and found that every region of the contiguous United States will reach 2 degrees Celsius 10 to 20 years before the global average gets there.

The Northeast’s emergence as the leader of the pack, however, was unexpected. “That was a big surprise to me, actually,” Karmalkar says. According to their results, by the time the world hits an average of 2 degrees of warming (which they project will happen between 2040 and 2050, depending on carbon emissions), the Northeast will have already seen the mercury rise by 3 degrees.

The dramatic temperature increases and associated weather patterns that are outlined in the researchers’ paper aren’t new to hydrologists, ecologists, and other resource planners working across the Northeast. The time line of these changes, however, is news, and it has added a great sense of urgency to their work. “Based on the rates of warming projected, in another few decades the Northeast will not be the same as it was 50 years ago, or even today,” says Michelle Staudinger, a marine biologist at NECSC.

So, what does this look like on the ground? Scientists have already observed species starting to shift their geographical ranges in response to climate change, and rapid warming in the Northeast could make those shifts happen even faster.

For example, if unseasonal weather makes winter precipitation fall as rain instead of snow, snow-dependent species like the snowshoe hare and Canada lynx could disappear from the region. And since wildlife and pollinator-dependent flowers can respond differently to warming, premature migration or breeding could lead to missed connections among species that rely on one another to survive and thrive.

Meanwhile, the milder weather could welcome invasives. Toni Lyn Morelli, a U.S. Geological Survey research ecologist at NECSC, warns of the southern pine beetle. As winters warm, this invasive insect is creeping up the Eastern Seaboard, leaving swaths of dead pines in its wake. The invader could soon reach New England, and Morelli says “this will disrupt the forest communities that people and wildlife depend on.”

Oh, and let’s not forget parasites—like the hordes of minuscule winter ticks that are taking down full-grown moose in Maine and New Hampshire and the deer ticks that cause Lyme disease.

You’d be forgiven for wondering how so many nasty consequences could happen within the generally “acceptable” range of global warming. Well, Karmalkar articulates a fact that climate scientists have been saying for years: “There is nothing magical about 2 degrees Celsius,” he says. No one has promised that keeping the global average temperature below 2 degrees of warming is safe; rather, as the paper notes, “it emerged as the least unattractive course of action.”

Still, international targets are a crucial foundation for regional action. Carbon dioxide mixes rapidly in the atmosphere and remains there for decades, meaning whether it comes from Beijing or Dallas, the pollution soon becomes everyone’s problem. The key is to think globally, act locally.

Karmalkar is currently looking into what might make the Northeast such a hot spot, but in the meantime he has a couple of ideas. Snow reflects between 80 percent and 90 percent of incoming sunlight back into the atmosphere, so if the white stuff starts to disappear, that extra heat gets absorbed by the land instead (the same phenomenon is underway in the Arctic as reflective sea ice melts). The Gulf of Maine, which stretches between Cape Cod and Nova Scotia, is also heating up rapidly, and it’s possible that the body of water could be affecting temperatures all over the Northeast—not to mention that the rising temperatures are decimating the gulf’s cod population, the backbone of New England’s fisheries for centuries.

Whatever the reason behind the Northeast’s fever, Staudinger says there are tools and strategies—like curbing carbon pollution and restoring habitats—to help human and ecological systems adapt to and mitigate climate change. “But action must start now,” she says. “We cannot wait.”

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