Unusually Warm Sea Water Boosted 2017's Catastrophic Hurricane Season, $265 Billion in Damage
SILVER SPRING, MD – September 28, 2018
The catastrophic 2017 hurricane season – which included such monsters as Harvey, Irma and Maria – was fueled in part by unusually warm ocean water, a new study suggests.
According the study, Atlantic hurricanes in recent years have become much more powerful and bring more abundant rainfall due to global warming.
Satellite data showed an average increase in wind speed in hurricanes by 21 kilometers more than 30 years ago. Every decade, this figure increased by 7 km.
The wind speed is influenced by factors like sea surface temperature, humidity, heat held by different water layers. In recent years, sea surface temperatures have been variable, affecting the intensity of natural disasters. This phenomenon is particularly pronounced in the Central and Eastern Atlantic.
According to experts, the maximum intensity of storm showers has increased by 30% over the past 60 years.
Sea water in the main hurricane development region of the Atlantic Ocean averaged 0.7 degrees warmer than normal for the entire 2017 season, which is unusual for a full six-month time period, Murakami said.
"We show that the increase in 2017 major hurricanes was not primarily caused by La Niña conditions in the Pacific Ocean, but mainly by pronounced warm sea surface conditions in the tropical North Atlantic," the study said.
La Niña, a periodic natural cooling of the tropical Pacific Ocean, tends to increase hurricane activity in the Atlantic.
The key factor controlling Atlantic major hurricane activity appears to be how much the tropical Atlantic warms relative to the rest of the global ocean, according to the study.
And because of human-caused global warming, the study said similar favorable conditions for fierce hurricanes will be present in the years and decades to come.
Last year, six major hurricanes formed, twice the recent average. By 2100, that average could soar to five to eight major hurricanes a year, according to the study published Thursday in the journal Science.
The researchers used computer simulations to pinpoint different climate conditions and also used the computer models to make predictions about the future.
The three big hurricanes in 2017 caused an estimated $265 billion in damages during a year that shattered all records for U.S. economic losses due to extreme weather, NOAA said.