As we start the slide toward winter, a long-range forecast should send a chill through Mainers who love the season’s snow and cold.

Winters in mid-21st century America will be warmer and shorter than they are now, an article in this month’s Journal of Climate said, sounding another alarm about the impacts of global warming.

In case your dentist’s office doesn’t have any copies in the waiting room, the research paper published in the journal predicts that global warming will fall hardest on winters in North America. In Maine, the study found, winters should average between 5.4 and 5.9 degrees Fahrenheit warmer from 2041 to 2070, compared to the last 29 years of the 20th century. Springs will be about 2.7 to 3.2 degrees warmer, with summers and autumns about 3.8 to 4.3 degrees warmer.

The study didn’t address how the rising temperatures would affect sea levels.

Subfreezing days will decline sharply, although parts of North America will see greater impacts than the Northeast. Temperatures are expected to shoot up sharply during the winter in northern Canada, for instance, and the number of freezing days is expected to drop most precipitously along the borderline between the northern tier of states and the South, in states such as Tennessee, Kentucky and Missouri.

The authors note that subfreezing days in those regions don’t get much below 32 degrees anyway, so it won’t take much warming to keep temperatures above freezing in those parts of the country.

But even southern Connecticut may see subfreezing days disappear, the study said.

The western and mountain states also are forecast to see significantly warmer temperatures and fewer freezing winter days than the Northeast, the study said.

Although the period covered is still more than two decades off, Andrew Pershing, chief scientific officer and ecosystem modeler for the Gulf of Maine Research Institute, said some of the effects already are being seen in Maine, particularly along the coast, where the climate is heavily influenced by the Gulf of Maine, one of the fastest-warming spots on the planet.

Pershing noted that one year does not a trend make, but temperatures in Maine this September – even with a bit of a cool-down this weekend – are more reminiscent of late August. Water temperatures, he said, are currently close to what used to be midsummer peaks in the last century. This year’s meteorological summer was the warmest on record.

But “it’s important to remember that this study is talking about average conditions,” Pershing said by email. “Any given year could be different than what the model predicts.”

Pershing said the research shows that winter-like weather will decline and those projections jibe with what his research shows in the Gulf of Maine: springs arriving earlier and autumns later. And, as in the Gulf of Maine, the biggest impact is in autumn, with summer temperatures holding on longer, he said, more than spring temperatures heating up sooner.

The biggest impact of the change in climate will be on the Maine coast, he said, because of the influence of those warmer ocean waters. Colder inland places will see warmer winter temperatures and fewer subfreezing days but perhaps not to the degree seen in coastal locations, such as Portland and southern Maine. He said while the models used by researchers suggest a bigger overall impact of global warming on winters than summers, his research – and recent experience – indicates that winters are, and will continue to be, much more variable than the summers.

“Think of the contrast between winter 2015 and 2016,” he said. Still, “this means the summer warming trend will be more noticeable, at least in the short term.”

Pershing said the jury is still out on the impacts of the warming trend.

What is clear, however, is that many species, including humans, will be affected.

“Changes in seasonality are very important to animals, plants and people,” Pershing said. “Many species use temperature cues to trigger their migration or breeding. Other biological events are more tied to day length (which won’t change in the future). This can create mismatches between different processes.”

In the meantime, winter fans can take comfort in the Old Farmer’s Almanac and the Maine-based Farmers’ Almanac, both of which are predicting that this winter will be cold for Maine. And the outlook for next spring is for cooler-than-normal temperatures, with a cooler-than-normal summer to follow.