The 2023 hurricane season was the fourth most active since 1950, with 20 named storms forming and tearing across the Atlantic. The ocean’s water ran much warmer than usual for much of the summer, breaking previous temperature records and fueling the rapid development of several major cyclones.
Somehow this year seems even worse.
This is largely because the Atlantic never cooled over the winter. Now surface temperatures are rising again, shattering last year’s records and turning the ocean into a powder keg for tropical storms. Major forecasters predicted earlier this year that 2024 would be the most active hurricane season in recorded history, with as many as 25 named storms possible.
One sign that this prediction is well on its way to reality: Before the end of June, the season’s first major hurricane had already formed over the Atlantic Ocean. Over the weekend, Hurricane Beryl strengthened to Category 4 strength in just a few hours as it rolled over the ultra-warm waters of the Caribbean Sea. The storm made landfall in Grenada on Monday morning with winds of nearly 150 miles per hour. At the time of publication, the hurricane was poised to track toward Jamaica before moving toward Mexico later in the week.
Beryl set a number of records on its way to the islands of the Caribbean: it is the earliest storm to reach Category 4 intensity in recorded history, and the only one to do so in the month of June. it is one of only seven hurricanes to develop to Category 4 intensity in less than 42 hours, and by far the earliest storm to do so. This is also the strongest storm in history to hit the Lesser Antilles, the archipelago of small islands east of Puerto Rico known colloquially as the “graveyard” because hurricanes there often dissipate amid strong wind shear before they can do much damage.
“It’s very early for this level of a severe storm, and the rate at which it has increased is incredible,” said Jill Trepanier, a professor at Louisiana State University who studies tropical storms.
Hurricane Beryl could never have formed where and when it did, were it not for the unprecedented heat in the Atlantic Ocean. Surface temperatures heading into hurricane season were as much as 3 or 4 degrees Fahrenheit Above average.
The scorching temperatures have baffled meteorologists and climate scientists, who still cannot explain why the sea has remained so warm for so long.
“We just don’t have a good answer,” said Brian McNoldy, a senior research fellow at the University of Miami and an expert in hurricane and ocean climatology. “[The Atlantic] never really cooled off, and now it’s breaking records again.”
To be sure, climate change is part of the equation: The world has warmed by about 1.5 degrees Celsius since pre-industrial times, and the oceans have absorbed much of that increase, leading to warmer baseline temperatures year-round.
McNoldy also told Grist that a number of additional weather phenomena may be contributing to the recent rise, though none explain the extent of the anomaly. The El Niño weather phenomenon may have played a role in raising temperatures last year, and a weaker than usual high pressure system around Bermuda could keep them high this year. The baseline temperature of the Atlantic Ocean also oscillates up and down every few decades, as does solar activity that heats the ocean.
But this and other possible ocean-warming events – like A 2020 international regulation that reduced sulfur emissions from shippingwhich may have contributed to marginal ocean warming, or the 2022 Hunga Tonga volcanic eruption – are all insufficient to explain the remarkable variation in normal ocean temperatures seen this year, according to McNoldy. Instead, like Elizabeth Kolbert wrote in the New Yorker in Marchcould the surge be proof that “we may not understand how fast the climate is changing.”
Although last year’s sea heat also led to predictions of a very active hurricane season, the US and the Caribbean got incredibly lucky. Almost all the storms that formed in the Atlantic turned northward or died out before reaching land. The monstrous Hurricane Lee had just grazed the edge of Eastern Canada, and the only major landfall in the US was made by Hurricane Idalia, which hit the least populated segment of Florida’s coast. This delay meant that the US avoided billions of dollars in damage, tens of thousands of destroyed homes and a further death spiral in its beleaguered insurance markets.
If Hurricane Beryl is any indication, that luck won’t repeat itself this year. The end of the most recent El Niño creates an even more favorable environment for storms to form, according to John Cangialosi, a senior hurricane specialist at the National Hurricane Center who tracked Beryl as it made landfall.
“You don’t often see the forecast stacked to one side like that, but that’s the case this year,” he told Grist. “There’s nothing that really mitigates it.”
