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Climate Change Packs Twice as Many Storms Into Hurricane Season

Climate Change Packs Twice as Many Storms Into Hurricane Season

Atlantic hurricane records go back to 1851, and in all that time the ocean has never piled up so many storms in such a short span as this year.

So far 11 storms have formed since May. This is now the earliest date on record for a storm with a “K” name, after meteorologists identified Tropical Storm Kyle on Friday. Five have hit the U.S., and the current pace eclipses 2005 when a record 28 storms, including Hurricane Katrina, roared out of the Atlantic. While 2020 storms have been weak, the lack of fierceness won’t come as a relief to anyone in New York or the Northeast who lost power for the better part of a week after Hurricane Isaias

Storm season in the Atlantic hasn't really started yet. On paper, annual risk of hurricanes runs from June 1 to November 30, but long-time observers know that things don’t really get heavy until the end of August. Bill Gray, the late Colorado State University professor who pioneered seasonal hurricane forecasting, would walk through his offices ringing a bell on August 20 reminding students that the real season was just beginning.

Climate Change Packs Twice as Many Storms Into Hurricane Season

The weeks from about Aug. 20 to the end of September are when the Atlantic between the Caribbean Sea and Cabo Verde off the coast of Africa becomes super charged. This stretch of ocean is called the Main Development Region, and it’s where the vast bulk of history's most deadly, destructive, and infamous hurricanes have been born.

As a result of climate change, which has raised global average temperatures around 1° Celsius, meteorologists have been warily updating their seasonal forecasts. A warmer-than-normal Atlantic combined with decreased wind shear across the basin has created consensus that there will be more storms.

Earlier this month, Colorado State increased its August outlook to 24 storms, up from 20 in July. The next day the National Oceanic and Atmospheric Administration increased its outlook to a spread of 19 to 25, up from 13 to 19 in May. Forecasters working for the federal government have never called for 25 storms in a single season before, said Gerry Bell, lead forecaster with the U.S. Climate Prediction Center.

How would those tallies for 2020 stack up against an average season? It would be like undergoing two complete seasons in a single year. The 30-year average is for 12 storms to be named in a single six-month Atlantic season. A system is named when its winds reach 39 miles (63 kilometers) per hour and it becomes a tropical storm.

An interesting side note is that many of this year's weaker storms have garnered some criticism of the National Hurricane Center. The assertion, often repeated by climate change deniers, is that storms are being named now that wouldn't have been named in the past, thus upping the numbers. It's a spurious claim, according to Louis Uccellini, director of the National Weather Service. “We have not changed the criteria of actually naming storms,” he says, “we just have better ways of identifying them.”

The Weather Service currently has a relatively new geostationary satellite looking down on the Atlantic that can show weather in granular detail. The images are so precise that Uccellini often pulls out his phone to show off the pictures the Weather Service is getting from outer space. That’s just one of the tools forecasters use when naming these systems.

As August winds down and people from Texas to New England shake off the damage from the storms that have already dropped on their heads, chances are they haven’t even seen the half of it.

©2020 Bloomberg L.P.