Chicago has seen nary a snowflake since before Christmas — a record in a city that averages 40 inches of snow in the winter. In Washington, D.C., the famous cherry blossoms are set to bloom two weeks ahead of schedule, marking the end of an uncommonly warm winter and the early arrival of spring.
In normally cold regions, the record-setting heat— and the opportunity to wear shorts and drink iced tea in February—might seem like a blessing. But for the ecosystems we depend upon, the shortened winter threatens turmoil.
In nature, timing is everything. In a spring, flowers lend their nectar to bees, and bees pollinate those flowers. When flowers bloom too soon, however, they risk losing their petals and nectar before bees show up. Fewer bees mean less pollination, and so forth.
But if both species resurface at the onset of spring, why would they fall out of sync? The answer is that they respond to different cues. Some plants, like Washington’s cherry trees, bloom after experiencing several warms days in a row. Others respond to sunlight, blossoming only after days grow longer. Pollinators — such as birds, bees, bats, and butterflies—have evolved to take advantage of these subtle, seasonal cues.
In a normal year, these cues more or less line up as anticipated, leading the birds and the bees to discharge their vernal duties at roughly the appropriate time. But climate change is blurring the line between winter and spring — a phenomenon scientists call season creep — and many species of both flora and fauna are struggling to adapt.
Even when plants and pollinators are in sync, season creep can thwart the growth of vegetation. Seeds that take hold during a balmy stretch in February may perish in a cold snap come March. Full-grown plants sprout leaves, flowers or fruit that wilt when chilly weather returns. Experts describe a warm winter spell that spurs flora and fauna to reemerge ahead of schedule as a false spring.
A false spring can also be extremely costly to farmers and, by extension, consumers. In 2012, an especially warm winter followed by freezing temperatures ravaged fruit trees in Michigan, costing growers half a billion dollars. The problem is likely to get worse in the years to come. A 2015 study found that climate change will produce more false springs in the Midwest and elsewhere, imperiling fruit crops.
Even an the absence of a late-season frost, a warm winter can wreak havoc on agriculture. Sugar maples, for example, only produce sap in cold weather. Rising temperatures have stunted syrup production.
Warmer winters do, however, tend to make people pay closer attention to the overall trend of anthropogenic climate change. A Gallup poll conducted at the end of last winter — the warmest on record in the United States — showed an increase in the number of Americans who believed the effects of climate change had already begun.
Granted, not everyone is equally persuaded by personal experience. Research suggests that those who are already concerned about climate change are more likely to perceive exceptionally warm weather as a deviation from the norm.
This year’s unusually mild winter has prompted many Americans to consider the implications of climate change. Chicago meteorologist Tom Skilling attributed the city’s snowless winter to global warming. In nearby St. Paul, Minnesota, civic leaders alarmed by the unusually warm weather are working on a climate action plan. Anne Hunt, the city’s environmental policy director, told the St. Paul Pioneer Press, “It’s not supposed to be 65 degrees in February, or rain on Christmas.”
By contrast, the mild winter has done little to sway federal policymakers. From the Oval Office, President Trump has proposed gutting federal climate programs and debated pulling out of the Paris Climate Agreement.
From the Lincoln Bedroom, he can see the cherry blossoms just beginning to emerge.