As Hurricane Milton bears down on Florida, fueled by a record-hot Gulf of Mexico, a new analysis has shown how the Gulf’s heat that worsened last month’s Hurricane Helene was 200 to 500 times more likely because of human-caused global heating.
Helene, one of the deadliest storms in US history, gathered pace over the Gulf before crashing ashore with 140mph (225km/h) winds.
The new analysis found climate change increased by 10% the amount of rainfall hurled down by the hurricane, which left more than 220 people dead across six states as it barreled north two weeks ago, flattening and drowning towns, tearing up roads and severing water supplies. It also made Helene’s winds about 13mph (21kph), or 11%, more intense.
The burning of fossil fuels has made storms as severe as Hurricane Helene about 2.5 times more likely than they were in the pre-industrial age, the multinational group of scientists at the World Weather Attribution group stated. Should the world warm by 2˚C above this pre-industrial period, which will occur without major cuts to emissions, storms such as Helene will get a further 10% more rainfall, the study found.
A study by Climate Central published on Monday found the sea surface temperature around Milton’s path was 400-800 times more likely because of the climate crisis.
The speedy analysis of Helene comes before the impending landfall of Milton which also grew in strength over the Gulf of Mexico, stunning scientists by ballooning from a category 1 storm to a category 5 event, with maximum winds of 180mph (290kph), in just nine hours.
Both storms rapidly intensified over the Gulf, with researchers pointing to exceptional seawater heat as a key factor in fueling the hurricanes. Since this summer, the surface and deeper waters of the Gulf have been at record, bathtub-like temperatures, with Milton set to pass over a patch of water close to Tampa that is around 2-3˚C hotter than usual.
Hurricanes gain strength from hotter oceans and a warmer atmosphere, with this heat adding to the pace of the storms while also loading them with extra moisture that is then unleashed as pounding rainfall, causing the sort of catastrophic flooding that submerged communities as far inland as western North Carolina when Helene hit.
Scientists noted that a warmer atmosphere is also able to hold more water vapor at a rate of about 7% per degree of warming. Currently, the world has warmed by at least 1.3˚C since the pre-industrial era and there are fears that this may be accelerating.