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This Thursday, September 7, 2017, a satellite image made available by NOAA shows the eye of Hurricane Irma, left, just north of the island of Hispaniola, with l & # 39; Hurricane Jose, right, in the Atlantic Ocean. Six major hurricanes – with winds of at least 111 mph (178 km / hr) – swept the Atlantic in 2017, including Harvey, Irma and Maria, who struck parts of the United States and Caribbean. (NOAA via AP)
Last year, the warmer waters of the Atlantic caused the unusual number of major cyclones, according to a new study that predicts that the region could experience a few more storms each year by the end of the century.
Last year, six major hurricanes, with winds of at least 111 km / h (178 km / h), invaded the Atlantic, including Harvey, Irma and Maria, who struck regions of the United States and the Caribbean. Since 2000, the Atlantic has averaged three major hurricanes a year. Before that, the average was closer to two.
According to a study published in Thursday's newspaper, it could go up to five to eight major hurricanes a year around 2100. Science .
"We will be seeing more active hurricane seasons like 2017 in the future," said lead author, Hiro Murakami, climate specialist and hurricane specialist at the National Oceanic and Atmospheric Administration.
So far this year, only an Atlantic hurricane, Florence, has reached a major status.
Hot water serves as fuel for hurricanes. The water must be at least 79 degrees (26 degrees Celsius) for a storm to form. The warmer the water, the more resistance it can withstand, says Brian McNoldy, a hurricane researcher at the University of Miami.
Murakami found that a combination of natural conditions and human-caused climate changes made the waters warmer in a key area, which caused more major storms. This area is essentially a large box located south of Florida and north of South America, which extends east to Africa.
Global distribution of tropical cyclone trajectories for a historical simulation by climatic model (top) HiFLOR and observations (bottom) from 1979 to 2012. Figures for each basin show the average annual number of tropical storms. The trajectories of the tropical storms are colored according to the intensity of the tropical storms, classified according to the scale of the winds of Hurricane Saffir-Simpson[eg tropical depression (TD), tropical storms (TS) and C1 – C5. This result underscores that the HiFLOR climate model is capable of simulating intense global hurricanes, as observed. Credit: Hiroyuki Murakami
Some of the most powerful hurricanes in the Atlantic form off the west coast of Africa, then head to the Caribbean and the east coast of the United States.
The water in this big box – the main hurricane development region – averaged 0.7 degrees (0.4 degrees Celsius) warmer than normal for the entire 2017 season, which is unusual for a six months, said Murakami.
The Murakami study used computer simulations to isolate different climatic conditions. Although his research showed both natural and man-made causes of burning coal, oil and gas, Murakami said he could not separate them enough to see which was bigger. .
Left: Predicted anomaly of hurricane density in 2017 compared to the 1980-2017 mean. Right: Major anomaly in hurricane density observed in 2017. Units: number per cell 2.5 ° × 2.5 ° per season. This comparison shows that HiFLOR predicted the locations of the main active hurricanes of 2017, as observed in the real-time forecasts. HiFLOR has also predicted the location of major hurricanes on the Pacific, as has been observed. Credit: Hiroyuki Murakami
He used computer models to project himself into the future. The Atlantic should warm up faster than the rest of the world's oceans. This difference is why Murakami said that the number of major storms would probably increase by two or more on average.
Some outside experts have had problems with some parts of Murakami's study.
McNoldy said it was logical that unusual hot water was to blame in 2017, but he was not quite ready to point fingers at global warming.
"The hurricane season is not just happening as the climate warms up, but the variability is huge," McNoldy said in an email.
Kevin Trenberth of the National Center for Atmospheric Research criticized Murakami's study for not taking into account the strong increase in ocean heat in deeper areas, which is also due to climate change.
Gabriel Vecchi of Princeton University said some computer simulations did not show the fastest warming in the Atlantic.
Explore more:
Science says: Hawaii hurricanes are rare, but become less common
More information:
H. Murakami el al., "The dominant effect of the relative warming of Atlantic tropical waters on major hurricanes", Science (2018). science.sciencemag.org/lookup/… 1126 / science.aat6711
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