Winter Is Cooked

Bing Crosby’s performance of “White Christmas” has, in recent years, sounded to me like an elegy. Some people might still get white Christmases, but where I live, in New York City, 2002 is the last time any snowflakes fell on Christmas Day. That is not a statistic of climatalogical significance, really. It’s more like an omen.

This winter most places in the U.S. should expect less snow than what many people—and the historical record—would consider normal. Climate change might be making summer days and nights hotter, but across most of the U.S., winter is getting warmer faster than any other season. Cold streaks are shorter, freezing nights are fewer, and extremely cold days are just not as cold. The places with the most dramatic warming are also some of the country’s classic winter wonderlands: In Albany, New York, winter is 6.8 degrees (Fahrenheit) warmer on average than it was some 50 years ago, according to an analysis by the nonprofit research group Climate Central. Winters in Concord, New Hampshire, and in Green Bay, Wisconsin, are each 7 degrees warmer, and winter in Burlington, Vermont, is more than 8 degrees warmer. In the places of much of America’s winter mythmaking, the image of a reliably snow-frosted landscape might be more suitably replaced with an image of bare trees and rain.

Snow will still fall for many years to come, sometimes in great quantities. But both the extent of snow cover in North America and the length of the season that would support it have been gradually shrinking. Springtime snows are particularly disappearing. And last winter, researchers identified a “snow-loss cliff”—an average winter-temperature threshold below which snowpack is fairly stable, but above which snow loss happens fast. Justin Mankin, a climate scientist at Dartmouth University who contributed to that finding, lives in New Hampshire, which exists well on the other side of that snow-loss cliff, where each additional degree of temperature rise dramatically diminishes snowpack. He now considers the “marginal use cost” of cross-country-ski gear he bought for his kids to be going up and up. “There’s really no snowmaking for cross-country skiing. You just have what nature’s giving you,” he told me. And now there are simply fewer days with worthy conditions to go cross-country skiing than there once were.

When I called him this week, he could see fresh snow outside his window. But that is still perfectly in line with climate predictions. “This is the kind of cognitive dissonance of global warming writ large that we need to hold,” he said. “There will be winters where there probably won’t be much snow accumulation. And then there’ll be other winters where there will be.” What will change—and what already has—is any kind of consistency. The snow system will get far more jumpy with each additional degree of warming. “Snow just doesn’t have the reliability that it has had in our imagination from the 20th century. That’s just gone,” Mankin said. “That’s the thing that is challenging our imagination for a place like New Hampshire.”

But winter precipitation isn’t going away. A study published in September found that the likelihood of extremely wet winters, especially in the Northeast and Midwest, is set to rise significantly. Whereas about one in 30 winters would be classified as very wet now, that rate could rise to six or seven winters out of 30 by the end of this century. But because temperatures will be higher, much more of that precipitation will fall as rain, rather than snow.

Akintomide Akinsanola, a climate scientist at the University of Illinois at Chicago and the lead author of that paper, told me he’s lived in Chicago for four years without seeing one of the midwestern city’s notorious major winter storms. His findings imply that most places across the country (except the southern Great Plains region) should be girding themselves for more winter flooding as the century wears on. “The average person is going to experience that firsthand,” he told me. Most places should be planning for that future, and thinking about how they will withstand those new extremes.

In parts of the U.S. that rely on snowpack for water, such as the Mountain West, the implications of both Mankin’s and Akinsanola’s papers are about water security. But in the Northeast and Midwest, that research points to a less concrete loss, of ice fishing and pond skating and dogsledding, and other parts of life that just aren’t as possible in a sopping wet, muddy winter. The identity of these places will continue to vanish as long as the global temperature keeps going up, which it will until carbon emissions halt. “The odds of a winter being snow-free just increases with each gigaton of emissions,” Mankin said. In New Hampshire, he is expecting both “mud season” and “stick season,” when trees are bare of leaves but also bare of snow, to extend further into the best part of the year in his state, when downy white should be blanketing everything.