AMHERST — When world leaders negotiated the Paris Climate Agreement in 2015, they set a goal to limit global average temperature rise to below 2 degrees Celsius above pre-industrial levels.
But while this target is easy to communicate to the public, regions around the world are not warming at the same pace. In the Northeast United States, a study conducted by the Northeast Climate Science Center at the University of Massachusetts Amherst indicates the region will reach the 2-degree threshold 20 years before the world as a whole.
The regional differences are another consideration when understanding climate change: how government agencies, scientists and planners should direct resources given warming trends in some parts of the world are not as rapid as others.
“From the point of view of planning, we probably have less time to act than many other regions,” said Ambarish V. Karmalkar, who authored the study along with Raymond S. Bradley.
Karmalkar said the benchmarks set out in Paris brought on a wave of questions in the science community about how parts of the world will fare when the globe as a whole reaches that 2 degree (3.6 degree Fahrenheit) threshold.
“Essentially, what we tried to find out, is that when the global average temperature, global warming, reaches two degrees, how much temperature increase will we see here locally?” Karmalkar said of the study, published in January in the journal PLOS One.
Karmalkar said if the world is successful in limiting temperature increases to 2 degrees Celsius, the study shows the Northeast will still see a 3 degree increase.
He added predicting a precise year for New England to cross the 2-degree mark is difficult, but that if emissions do not decrease, then “50 percent of the projections that we look at suggest that we would reach that 2-degrees threshold before 2050 or as early as the 2030s.”
The real world impact of warming?
A striking reality for humans on coasts could be intense sea level rise. In a separate study, published last year in the journal Nature, climate scientists write that if greenhouse gas emissions continue to climb, sea levels could rise more than a meter by 2100.
The study was authored by climate scientists Robert DeConto at UMass and David Pollard at Pennsylvania State University. DeConto said low-lying Boston could face about 5 feet of sea level rise in the next century, “but the good news is that an aggressive reduction in emissions will limit the risk of major Antarctic ice sheet retreat,” he told UMass News & Media Relations.
Signs of climate change are already evident in New England.
Michael Rawlins, another researcher at the Climate Center, used National Oceanic and Atmospheric Administration data to show the Northeast saw 10 straight months where the average temperature came in warmer than 30-year norms.
That trend stopped this year, according to the data, when the average temperature in March was more than 2 degrees Fahrenheit below normal. Rawlins would not directly connect the 10-month string of warmer-than-normal months to climate change, but said such a phenomenon is more likely with global warming.
“Your chances of seeing a warmer than normal day, month or season are greater when you have a warming climate,” Rawlins said.
Wildlife researchers in New England are seeing impacts first-hand. For example, scientists from Maine to Vermont are watching moose fall victim to parasitic winter ticks, which latch on by the thousands in the fall before detaching in April.
“Of course we’re all aware of the warming climate and the shorter span of snowcover,” said Cedric Alexander, the moose project manager for Vermont Fish and Wildlife. “It comes later in the fall and it’s gone earlier in the spring. That’s beneficial to winter ticks because when they drop off in April, if they fall onto snow, their survivorship is much lower than if they fall onto bare ground.”
Rawlins said we will still see heavy snow in the depths of winter, but said to expect less snowfall in “shoulder” months.
“Certainly climate models project that we will see less snow in the ‘shoulder’ seasons,” he said, “less snow in October and April, for example, and more rain as the climate warms.”
Jack Suntrup can be reached at email@example.com.