Warm Atlantic waters led to 2017’s hyper hurricane season, study says
Scientists say there could be eight major hurricanes in the Atlantic every year by the end of the century.
Warm waters in the Atlantic Ocean were a driving factor behind last year’s extraordinary hurricane season, scientists have said.
The study also predicts that the Atlantic could see more enormous and powerful hurricanes every year by the end of the century.
There were six major hurricanes in 2017, with winds of at least 111 mph (178 kph), that caused devastation to parts of the US as well as some Caribbean nations.
Historically, the Atlantic averaged only two major storms a year, but since 2000 it has been closer to three.
By the year 2100 there could be eight major hurricanes a year, according to the study – published in the journal Science.
“We will see more active hurricane seasons like 2017 in the future,” said lead author Hiro Murakami, a climate scientist at the National Oceanic and Atmospheric Administration (NOAA).
In 2018, there has only been one major Atlantic hurricane, Florence, which killed at least five people when it battered the southeastern coast of the US.
Storms require waters of at least 26C (79F) to form, and the researchers explained how warm water fuels hurricanes by allowing a storm to form quicker.
Dr Murakami found a combination of natural conditions and human-generated climate change were behind waters being warmed in one particular area, which became a nursery for storms.
The key area is “a large box from south of Florida and north of South America, stretching all the way east to Africa” which was on average 0.4% warmer during 2017.
The most powerful hurricanes often form in the waters off the coast of west Africa and grow more powerful as they move towards the Caribbean and the US.
Dr Murakami said that the Atlantic was projected to warm faster than other oceans due to climate change, and that was why storms there were going to become a bigger issue.
University of Miami hurricane researcher Brian McNoldy, who was not part of the study, agreed that the unusually warm water was to blame for last year’s powerful storms.
He was cautious about the role of climate change, although he did not dispute that human activity was causing global temperatures to rise.
“Hurricane seasons don’t just keep getting more active as the climate warms though. There is enormous variability,” he said.