What a historic El Niño year means for Long Island's weather forecast

An El Niño climate pattern is strengthening in the tropical Pacific and could become one of the most intense in decades, scientists are warning. The shift is expected to peak by December and to last through next summer and is likely to cause severe heat and drought in some parts of the world and heavy rains and flooding in others.

For Long Island, the effects will be more mild — most likely a subdued hurricane season and a warmer winter.

El Niños are classified according to surface temperatures in the Pacific Ocean near the equator. If temperatures over three months average 2 degrees Celsius (3.6 degrees Fahrenheit) above normal, it’s considered a very strong El Niño. In mid-August, the weekly reading reached 2.7 degrees C (4.9 degrees F), according to the Columbia University Climate School’s ENSO tracker.

The National Oceanic and Atmospheric Administration, which has collected El Niño data since 1950, said the chances are better than two-thirds that this El Niño will be the strongest on record.

Shifting winds create global climate shifts

Global climate patterns shift between El Niño (warmer) and La Niña (cooler) periods, with neutral periods in between. These cycles, called the El Niño-Southern Oscillation, or ENSO, repeat every two to seven years, and have persisted for thousands of years.

El Niños emerge when trade winds in the Pacific weaken, and warmer waters flow east, triggering extreme weather around the world. The 1982 El Niño brought famine to Ethiopia; its appearance in 1997 led to drought and severe wildfires in South and Southeast Asia, flooding on South and North America’s Pacific coasts, and coral bleaching in tropical waters across the globe.

The coming year could bring life-threatening conditions to nearly every part of the world, experts have warned. The United Nations World Food Program announced in August that tens of millions of people across the Caribbean, Latin America, Africa and Asia could experience severe hunger because of crop failures; the agency is stepping up its efforts to prevent famine.

Is climate change strengthening El Niños?

While the patterns are natural and ancient, they are now arriving at a time when the planet is hotter than it has ever been during recorded history — and growing hotter every year as fossil fuel consumption continues to rise.

Scientists haven’t yet determined how much global warming may be supercharging El Niño cycles. "The climate record is really too short for us to say for sure that El Niño is getting stronger," Edmund Chang, a professor at Stony Brook University’s marine and atmospheric science school, told Newsday.

But some recent research suggests that the disruptions of climate change may be magnifying El Niño’s effects. Researchers at the University of Michigan did a chemical analysis of the ancient corals of the Galápagos Islands, whose yearly growth layers provide a natural record of the changing climate. 

Their study, published in the journal Science, found that El Niños have intensified by 36% in the past 40 years. And the El Niños of the past four decades were stronger than any in the 1,000 years before 1850, when CO2 levels in the atmosphere, and global temperatures, began to climb.

What will El Niño bring to Long Island?

Some parts of the globe will be spared the more devastating consequences of the coming shift — Long Island included. Chang, who studies the impact of ENSO cycles in the United States, said the main effects in the Northeast are a more muted hurricane season in late summer and fall and slightly warmer winters.

"Our prediction was for lower hurricane activity, and up to now it has been spot on," Chang said.

In winter, the shift sometimes brings more nor’easters, but warmer temperatures mean those storms might dump freezing rain rather than deep snow, he said. It’s less likely that New York will get the extreme cold that hit the region last winter.

"We largely know the impacts of El Niño," Chang said, but precisely how this cycle plays out, locally and globally, remains uncertain.

One thing some climate scientists are already predicting: The multiplying effects of El Niño and global warming will likely make 2027 the hottest year in recorded history.