Study: Warming Waters to Cause More Major Hurricanes

01 October, 2018

A new study predicts that warmer waters in the Atlantic Ocean will continue to increase the number of major hurricanes.

The study, published in the journal Science, was based on research carried out by the National Oceanic and Atmospheric Administration, or NOAA. Researchers say each hurricane season is likely to produce five to eight major hurricanes by 2100.

In 2017, six major hurricanes formed in the Atlantic. Three of them – Harvey, Irma and Maria – made landfall. The storms hit parts of the United States and Caribbean, causing loss of life and an estimated $265 billion in damages.

Since 2000, the Atlantic has averaged three major hurricanes a year. Before that, the average was closer to two. So far this year, only one Atlantic hurricane, Florence, reached major strength.

How was the study done?

The new study used a computer modeling system developed by NOAA to simulate different climate conditions. Researchers say they were able to correctly predict the active hurricane season in June 2017. Additional experiments showed that the main driver of the 2017 hurricane activity was a much warmer Atlantic Ocean.

Hiroyuki Murakami was a lead researcher on the study. He is also a climate scientist and hurricane expert at NOAA. He says the climate simulation system is an effective tool to help estimate current and future storm activity.

This Thursday, Sept. 7, 2017 satellite image made available by NOAA shows the eye of Hurricane Irma, left, just north of the island of Hispaniola, with Hurricane Jose, right, in the Atlantic Ocean. (NOAA via AP)
This Thursday, Sept. 7, 2017 satellite image made available by NOAA shows the eye of Hurricane Irma, left, just north of the island of Hispaniola, with Hurricane Jose, right, in the Atlantic Ocean. (NOAA via AP)

"This new method allows us to predict hurricane activity as the season is happening, as well as take into consideration the likely contribution of climate warming," Murakami said. "We will see more active hurricane seasons like 2017 in the future," he added.

Murakami told the Associated Press his team found that a combination of natural conditions and man-made climate change are making Atlantic Ocean waters warmer. Man-made causes included the burning of coal, oil and gas.

Warm water is important because it acts as a fuel for hurricanes. Water has to be at least 26 degrees Celsius for a storm to form. The warmer the water, the more a hurricane can resist forces that would cause it to weaken.

The Atlantic is predicted to warm faster than the rest of the world's oceans. This is why the study estimates the number of major storms will probably increase by two or more on average.

And warm water is especially affecting one important area, Murakami said. This box-shaped area includes a large territory south of Florida and north of South America, extending all the way east to Africa.

Some of the strongest Atlantic hurricanes form off the coast of West Africa, before heading west toward the Caribbean and the U.S. East Coast.

Ocean water in this box-shaped area averaged 0.4 degrees Celsius warmer than normal throughout the 2017 season. Murakami said the temperature was very unusual for a six-month time period.

Other experts raise questions

Some outside experts had issues with parts of Murakami's study. Brian McNoldy is a hurricane researcher at the University of Miami. He told the AP it makes sense that unusually warm water caused the extra hurricane activity in 2017. But he was not willing to completely blame climate change.

"Hurricane seasons don't just keep getting more active as the climate warms. There is enormous variability," McNoldy said.

Kevin Trenberth is with the National Center for Atmospheric Research. He took issue with the fact that the study did not include research on large increases in ocean heat in deeper ocean areas. Trenberth said this can also be caused by climate change.

I'm Bryan Lynn.

Bryan Lynn wrote this story for VOA Learning English, based on reports from the Associated Press and the NOAA. Kelly Jean Kelly was the editor.

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Words in This Story

simulate v. do or make something that behaves or looks like something real, but which is not

contribution n. something that helps produce or develop something

enormous adj. extremely large

variability n. capability of being varied or changed