The annual question of whether we will have a white Christmas reaches peak curiosity this week. However, recent studies and reports indicate that the probability of seeing snow at Christmas is becoming increasingly unlikely due to human-caused climate change. “With a warmer climate, it is likely that more winter precipitation will fall as rain rather than snow in many parts of the country,” said a 2021 report from Climate Central, a nonprofit science and communication organization.
“Climate change threatens symbols of the holiday season from Christmas tree growth, winter recreation, and cozy drinks to Arctic wildlife.”
Reduced snowfall and less snow cover could affect water supplies, transportation, travel, and recreation for millions of people, according to the Environmental Protection Agency. Reports show that as the globe warms, snow, overall, is decreasing. Between 1972 and 2020, the average portion of North America covered by snow decreased at a rate of about 1,870 square miles per year, an area roughly the size of Delaware.
In the U.S., climate change is already affecting the amount of snow that falls across the country. In several of the key ways that snow is measured – snowfall, snow cover, and snowpack – significant declines have been reported. “What we know about winter temperature trends is that winter is the fastest-warming season across most of the United States – and particularly so east of the Mississippi River,” said a research assistant professor of earth sciences at the University of New Hampshire.
“New England and the Upper Midwest are winter warming hot spots. We’ve seen some of the fastest winter warming trends in Burlington, Vermont, Milwaukee, Wisconsin, and Concord, New Hampshire.”
She added, “With snowfall, the ratio of precipitation that’s falling as snow versus rain has been shifting over time. As we get warmer temperatures, we’re going to be seeing more of our winter precipitation falling as rain instead of snow.”
On average, only about a third of the contiguous 48 states has snow on the ground on Christmas Day, but this figure has steadily dropped over recent years, according to FoxWeather.
“Average winter temperatures in particular have climbed more quickly than temperatures in other seasons, especially in the Northeast, where the American Christmas ideal emerged and evolved in the 19th century,” said a professor of environmental history at Georgetown University.
White Christmas likelihood declines
“Periods of extremely cold temperatures were much more common in the region during the middle of the 19th century, when the Little Ice Age was finally beginning to end.”
“Something like the ‘white Christmas’ ideal in American culture may have been influenced by the average snowfall that people experienced in the 19th century, or it may have stemmed from a particularly extreme stretch of winter weather,” he said.
Despite overall trends, some areas have not experienced a decrease in winter snow cover as much as expected. “Some parts of the United States, such as the Great Lakes region, appear to be snowier now than they were,” the professor explained. “Even in a world that is, on average, 2.7 degrees warmer than its late 19th-century average temperature, global snowfall should only decline by about 5%.
A warmer atmosphere can hold more water vapor, which often leads to greater precipitation. In regions where winter warming does not increase temperatures beyond the freezing point, there can actually be more snow on the ground even when winter temperatures rise.”
According to the National Oceanic and Atmospheric Administration, the 1991-2020 version of the white Christmas map shows more areas experiencing decreases in their chances of a white Christmas than increases. The gray area, where the chances of a white Christmas are less than 10%, has shifted noticeably northward across the South and upslope along the ocean-facing slopes of some of the West Coast mountain ranges.
To fit the weather service’s definition of a white Christmas, there needs to be at least 1 inch of snow on the ground. On average, about 38% of the contiguous 48 states have an inch of snow on the ground on Christmas Day, according to 21 years of data compiled. – Total snowfall has decreased in many parts of the U.S. since widespread observations began in 1930, with 57% of stations showing a decline.
– From 1972 to 2013, the U.S. snow cover season became shorter by nearly two weeks on average, NOAA reports. – From 1982 to 2021, the snowpack season shortened at about 86% of the sites where snowpack was measured, with the duration decreasing by about 18 days on average. The data underscores that as climate change continues, the likelihood of a traditional white Christmas diminishes year by year.
Cameron is a highly regarded contributor in the rapidly evolving fields of artificial intelligence (AI) and machine learning. His articles delve into the theoretical underpinnings of AI, the practical applications of machine learning across industries, ethical considerations of autonomous systems, and the societal impacts of these disruptive technologies.
