Accelerating trend of potentially dangerous warmer weather being driven by climate change, experts say

More than 100 million Americans endured temperatures of 95 degrees or hotter this week, and this weekend many Long Islanders will join them.

The National Weather Service on Friday issued a heat advisory for northwest Suffolk County and northern Nassau County from noon Saturday to 8 p.m. Sunday. Heat index values for those areas — what it feels like when humidity is combined with air temperature — were forecast to rise as high as 97 on Saturday. 

Heat records were broken all week elsewhere in the country. But this was the first heat advisory issued for Long Island this season, said Bryan Ramsey, a meteorologist at the weather service’s Upton station.

“It’s a heads up,” he said. “It’s going to be pretty hot, and it’s going to be hot for a while.”

This week's hotter temperatures, albeit a bit early, were not that unusual for the start of summer on Long Island. But they do reflect an accelerating trend of potentially dangerous warmer weather that's been driven by climate change, experts say.

The advisory warned that seniors and anyone with chronic health problems or mental health conditions was at increased risk. Homes without air conditioning can be much hotter than outdoor temperatures, the weather service said.

By Friday, a risk map of Long Island on the National Integrated Heat Health Information System website was bathed in red and orange: red for major, affecting anyone without effective cooling and hydration, and orange for moderate, affecting those particularly sensitive to heat. Only the East End and patches of the South Shore showed yellow, for minor risk.

An air quality alert has also been issued for Saturday.

Town supervisors across Long Island have turned community centers, government buildings and even an ice rink into cooling centers. They have extended pool and beach hours, sometimes as late as 9 p.m., and asked residents to check on vulnerable neighbors.

At North Shore University Hospital in Manhasset, Dr. Chid Iloabachie, associate chair of emergency medicine, said his department, which serves a relatively affluent area whose residents have access to home air conditioning or cooling centers, had seen few patients present with symptoms of heat related illness this week.

“But we always think about it,” because many of the hospital’s patients are elderly, he said. “The index of suspicion needs to be high: dizziness, nausea, vomiting, feeling weak, cramping.” 

Conditions across much of the eastern half of the United States this week are the result of a heat dome. National Oceanic and Atmospheric Administration meteorologists say that occurs when slow-moving high pressure air sinks toward the surface. The sinking air acts as a dome capping the atmosphere, trapping the heat instead of allowing it to lift. The result is a continual buildup of heat at the surface experienced as a heat wave.

“That dome is allowing hot, humid air to come up from the Gulf of Mexico and the southeast U.S. straight into the Northeast and straight into New York,” said Jase Bernhardt, associate professor in the Department of Geology, Environment and Sustainability at Hofstra University. “Also, given that we have direct sun angle, the longest days of the year, it’s allowing very hot days.”

Another factor, perhaps more dangerous than the attention-grabbing daytime highs, is that temperatures aren’t dipping much at night. “We’re seeing nighttime temperatures that don’t get below 70 on Long Island and in New York City,” Bernhardt said. “If you can’t cool off, you can’t sleep well, that’s maybe more dangerous.”

At LaGuardia Airport, for example, from Tuesday on, nighttime lows didn’t fall below 73 degrees, according to NOAA. In Centerport, the nighttime temperatures dipped as low as 68, about seven degrees higher than the historical norm.

NOAA data shows that the planet has been warming an average of 0.11 degrees Fahrenheit per decade since 1850. Human activities, primarily those that emit greenhouse gases, are causing the warming trend, according to the Intergovernmental Panel on Climate Change.

While climate scientists are often reluctant to tie any single weather event to global warming, NOAA data shows that heat waves are occurring more frequently than they have in the past.

An Environmental Protection Agency analysis of NOAA data from 1961 to 2021 for 50 metropolitan areas found more than six heat waves per year in the 2020s, about three times the rate of occurrence in the 1960s. The heat waves lasted longer, were more intense and occurred over a significantly longer season than they did in the past.

“Without climate change, this heat wouldn’t have been quite this warm,” said Jessica Spaccio, a climatologist at Cornell University’s Northeast Regional Climate Center. “We expect the frequency of heat events to increase.”