In much of America, especially in the normally cold north, the country experienced the winter months without, well, winter.
In the parka strongholds of Burlington, Vermont and Portland, Maine, the thermometer never dropped below zero. The state of Minnesota called the past three months “the lost winter,” warmer than the infamous “year without winter” in 1877-1878. Michigan, where mosquitoes were biting in February, offered disaster loans to businesses affected by a lack of snow. The Great Lakes set records for low winter ice, with Erie and Ontario being “essentially ice-free.”
According to the National Phenology Network, which tracks the timing of plants and insects, spring leaves are arriving across much of the country, from Colorado to New Jersey and from Texas to the Carolinas, three to four weeks earlier than the 1991-2020 average . and other natural signs of the seasons.
“Long-term warming combined with El Nino has kept winter from making an appearance in the U.S. this year,” said Yale Climate Connections meteorologist Jeff Masters, co-founder of the private company Weather Underground. Masters said he was bitten by a mosquito in Michigan this year, which he called crazy.
On Friday, the National Oceanic and Atmospheric Administration confirmed that the winter of 2023-2024 was the warmest in nearly 130 years of record-keeping in the United States. The Lower 48 states had an average temperature of 37.6 degrees (3.1 degrees Celsius), which is 5.4 degrees (3 degrees Celsius) above average.
This is just the latest in a series of broken temperature records, national and global, that scientists say are largely due to human-induced climate change from the burning of coal, oil and gas.
And it was the warmest American winter by a wide margin. The past three months have been 0.82 degrees (0.46 degrees Celsius) warmer than the previous record set eight years ago, which is “a pretty good jump above the previous record,” said Karin Gleason, chief of monitoring at NOAA’s National Centers for Environmental Information.
Last month was only the third warmest February on record. But Iowa passed its warmest February by 2 degrees, while parts of Minnesota were 20 degrees warmer than average for the entire month of February, Gleason said.
On February 11, Great Lakes ice cover reached a February record low of 2.7%.
A strong ridge of high pressure kept the eastern United States warm and dry, while California continued to be hit by atmospheric rivers, she said.
The European climate agency Copernicus said earlier this week that it was the warmest winter in the world, mainly due to climate change with an extra boost from a natural El Nino, which is changing the weather worldwide and providing extra warmth.
Over the past 45 years, winters in the United States have warmed faster than globally, with winters in the lower 48 states now averaging 2.2 degrees (1.2 degrees Celsius) warmer than in 1980, according to an analysis by NOAA- data by The Associated Press.
That’s likely because land is warming faster than the ocean, with much of the United States existing as land and most of the world as ocean, Gleason said.
Although the United States continues to warm, the pace of additional warming has slowed slightly since 2000, NOAA data show. Winter weather expert Judah Cohen of Atmospheric Environmental Research, a commercial firm outside Boston, blames Arctic Amplification for how climate change has made the Arctic three to four times warmer than the rest of the world and resembling weather patterns further south. to shift.
As the Arctic warms faster, the jet stream, which moves weather systems across the Earth, wobbles and weakens. That means the cold air trapped at the top of the planet, called the polar vortex, escapes its normal boundaries and drifts elsewhere, causing short bursts of frigid air that temporarily counteracts the overall warming trend in certain places, Cohen said .
That happened briefly in January, when winter “just made a cameo appearance in the Lower 48,” Cohen said. But this year, when the polar vortex swirled, it mostly hit Europe or Asia with bursts of icy air, and not the United States, so there was no offsetting effect on U.S. winter temperatures, he said.
Boston hasn’t even seen single-digit temperatures this year, with a winter low of 14 degrees, a record for no deep cold.
And snow? Forget it, at least in the east and north.
In Fort Kent, in far northern Maine, an annual dog sled race was canceled due to lack of snow. The city had had 46.8 inches (119 cm) of snow this year as of last week, just over half as much as normal, the National Weather Service said.
According to the Rutgers Snow Lab, snow cover in the United States was the second lowest on record in February and the third lowest in December, with only January above normal.
There are consequences for warm winters, says Theresa Crimmins, director of the National Phenology Network.
“Warm winters can also lead to earlier, longer and more abundant pest seasons because populations are not set back by the cold,” Crimmins said in an email. “Allergy season can also be worse: it starts earlier, lasts longer and results in more pollen in the air.”
Because it is warmer, trees and flowers can bloom early. Washington’s cherry blossoms are forecast to peak about two weeks earlier than in 2013. Early blooms can confuse the intricate timing of pollinators and birds.
“Many of the birds that migrate south in the winter use day length as a signal to come north in the spring,” Crimmins said. “In years like this, when plant and insect activity starts much earlier than normal, birds can miss out on maximum food availability by arriving too late. ”
But there is good news for California, as atmospheric rivers and snowstorms are likely to rebuild snowpacks and fill up reservoirs that had been dangerously low until a few years ago, Gleason said.
Winter weather expert Cohen, who lives outside Boston, joked that the US no longer has four seasons: “We have two seasons. We have summer and we have November.”
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Associated Press writer Patrick Whittle contributed from Portland, Maine.
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