Falling through ice and drowning is a perennial risk in northern communities where winter ice is a defining part of the environment. But to Leary, the four-wheeler accident stuck out as an especially harrowing one, in part because of its timing: It occurred in late March 2019, a time of year when the Kuskokwim River, which runs through Bethel, should be frozen solid and safe for locals to use as a highway to drive from place to place.
“I thought to myself as I was [going] out there — this shouldn’t be happening,” Leary said in an interview. “We should have at least another month of safe travel on river ice.”
Far from an isolated incident, Leary’s experience reflects a reality facing northern communities around the world: As winters grow warmer because of climate change, seasonal lake, river and sea ice is becoming treacherous. Now, a new study is warning that this trend could have widespread and tragic consequences.
The research, published last week in the journal PLOS One, examined records of more than 4,000 fatal winter drownings worldwide alongside weather and climate records. It found that winter drowning events “increase exponentially” as air temperatures approach 32 degrees Fahrenheit, the freezing point of water. The findings point to a potential for more drownings as winters become milder, with small children and people in remote Indigenous communities facing an acute risk.
“This is the saddest research I’ve ever done,” Sapna Sharma, an associate professor of biology at York University in Canada and the lead author of the new study, said in an interview.
In many northern countries, warmer winters are one of the clearest signals of climate change. In Canada, wintertime air temperatures have risen nearly six degrees over the past 73 years, faster than in any other season. In parts of Alaska, winter has warmed by closer to 10 degrees. In Finland, winters have warmed by about five degrees.
This rapid winter warming is having a clear effect on winter ice. Rivers, lakes and even parts of the open ocean that have long served as seasonal ice roads or sturdy platforms for fishing and recreation are freezing up later in the fall, thawing earlier in the spring and becoming less stable throughout the winter. A huge number of people face potential harm: Research published last year in Nature Climate Change found that a 1.8-degree Fahrenheit uptick in global average temperatures could cause 100 million people to lose access to a reliably frozen lake in winter.
“We know that lakes are warming; lake ice is melting earlier in the spring, forming later in the fall; and that we have more freeze-thaw events and thinner ice,” Sharma said. “And we wondered if that directly affected people.”
To answer that question, Sharma and an international team of collaborators compiled nearly 30 years of records of fatal winter drownings from coroners’ offices, local police stations and lifesaving societies in 10 countries that are home to seasonally frozen rivers and lakes, including Canada, the United