James McGowan fondly remembers ice skating every winter while growing up in Flatbush, Brooklyn. It was during the 1950s and 1960s, when his dad used to come home from work, spray down the backyard, and open the DIY rink for all the kids in the neighborhood.
“People would be out ice skating in the city as a regular after school activity,” McGowan said. Over the past several decades, he has noticed that it’s become harder and harder to skate outside in backyard rinks or the lakes peppered around the city—it just hasn’t been cold enough.
His experience isn’t just anecdotal. In New York City, the annual average winter temperature has risen about 3.2°F since 1970, according to data from the National Oceanic and Atmospheric Administration (NOAA). And across the Northeast, winters are warming three times faster than summers.
But at the same time, six of the 10 deepest snowstorms recorded in New York City have occurred over the last 20 years—quite a feat since snowfall records go all the way back to the 1860s, said Dominic Ramunni, a meteorologist at the National Weather Service in New York. This winter is no different. The Nor’easter at the beginning of February brought in 17.4 inches of snow, and Governor Cuomo declared a state of emergency. The storm was tied for the city's 16th largest, said Ramunni.
How can there be more frequent severe winter weather while it’s also getting warmer?
Climate change, said Judah Cohen, director of seasonal forecasting at Atmospheric and Environmental Research, a weather risk assessment company. Although it’s hard to attribute any particular weather event directly to climate change, these seemingly contradictory trends are both explainable by a warming planet. Here’s how.
Warmer temperatures from climate change are causing disruptions in the polar vortex, resulting in more frequent severe winter weather in New York City, said Cohen.
The polar vortex is a large area of low pressure and cold air near the north pole, and under normal conditions, the circular flow of air keeps the cold weather concentrated in one area. But according to NOAA, the Arctic is warming twice as fast as the rest of the planet, and Cohen’s research shows when the polar vortex is disrupted by warmer air, the cold air spills into other areas of the globe, creating arctic blasts.
“You can think of it like a spinning top,” said Cohen. “You bang on the top, it starts to wobble, it starts to meander. And where the polar vortex goes, so goes the cold air.”
An ice skater amuses a crowd with his hand springs in Brooklyn, January 18, 1923.
Higher temperatures during the winter lead the air to trap more water vapor, all while evaporation is increasing across warmer oceans and land. More moisture plus arctic blasts equal the larger number of snowstorms we’ve seen in recent years.
The result is that snowstorms in the Northeast are waning in early and late winter because of warmer temperatures, but there has been an increase in heavy snowstorms in mid-winter, Jennifer Francis, a senior scientist at the Woodwell Climate Research Center, said via an email. New York isn’t alone in feeling the effects of arctic disruption, as parts of Europe and East Asia are also impacted. This week, Scotland had the coldest weather in 25 years, according to the Met Office, the national meteorological service for the United Kingdom.
Polar vortex disruptions don’t happen every year, said Cohen, so there are still some milder years like 2020. According to the National Weather Service, that was one of the warmest winters on record and around 4 degrees above normal. And when polar vortex disruptions do happen, they don’t necessarily last throughout the whole winter. That’s why we can notice warmer winters and an increase in the frequency of severe winter weather simultaneously, said Cohen.
Not everyone agrees with the theory that climate change can contribute to disruptions in the polar vortex, a point that even Cohen admits. Amy Butler, a research scientist at the NOAA Chemical Sciences Laboratory, said via an email that she doesn’t think the connection is clear between the weakening of the polar vortex and anthropogenic climate change because the polar vortex naturally has periods where these disruptions occur.
“When we look at future climate change scenarios, there are an equal number of model simulations predicting that the vortex will strengthen in the future… as there are that predict the vortex will weaken,” Butler said.
The fallout from severe winter weather won’t be felt evenly across the five boroughs. It will likely be harder on low-income New Yorkers who depend on public transportation, for example. “What we're seeing with all sorts of disasters and including winter storms is that the impacts are many times disproportionately felt in certain communities, in particular non-white communities,” said Andrew Kruczkiewicz, a faculty researcher at the International Research Institute for Climate and Society at Columbia University.
Kruczkiewicz wants to know to what degree New York City is preparing for more frequent severe winter weather in the future. The Mayor’s Office of Resiliency, which is in charge of planning out the city’s adaptation to climate change, did not respond to Gothamist’s request for comment before publication.
Does all this mean that New York City’s past climate habits are gone for good, frozen inside memories of outdoor ice rinks? Not yet, said Francis. The region hasn’t permanently transitioned into a new climate zone, but she noted that summers are headed that way.
New York could move from what’s known as a humid continental climate to a humid subtropical climate by the end of the century unless there’s a rapid reduction in the emissions of greenhouse gases globally. That means by the end of the century, New York’s summer temperatures might look more like those in Juarez, Mexico, according to an analysis by ClimateCentral.
Our final fate is hard to predict, but Francis says we are likely to see a lot of variability. “As human-caused climate change continues unabated, New Yorkers should expect Mother Nature to throw even more tantrums: wild temperature swings, heavy precipitation events, and persistent weather conditions.”
And Cohen said he doesn’t expect the severe winter weather events we are experiencing now to let up any time soon. “The next 10 years, I see no reason for it to change. But after that, we don't know.”
New York City’s weather forecast for next week is consistent with that prediction: wintry precipitation is expected through Thursday.
