Extremely active Atlantic hurricane seasons are now twice as likely as they were in the 1980s due to global heating, according to new research that warns the climate crisis is supersizing storms that threaten life and property in coastal areas.
Climate breakdown has contributed to a “decisive increase” in intense hurricane activity since 1982, the study states. Researchers in Germany and Switzerland who undertook the analysis wrote that the growing hyperactivity of storms could be “robustly ascribed” to the rising temperature of the oceans.
The warming of the sea surface has “contributed significantly to more extreme tropical cyclone seasons and thereby to the fatalities, destruction and trillion-dollar losses that these cyclones have caused over the last four decades”, the research added.
Previous research has shown that while the number of hurricanes – often called cyclones when they happen in the Pacific – may not increase drastically due to climate change, the events themselves appear to be getting stronger and more destructive. A storm is considered a hurricane when it reaches sustained winds of 74mph or more and is measured between category 1 and 5 on the Saffir-Simpson hurricane wind scale for severity.
This intensification of storms, in which the energy and moisture held by a swirling hurricane is boosted by elevated heat from the ocean and atmosphere, has manifested itself in numerous recent disasters, including Hurricane Maria, a category 5 hurricane that reached 174mph and devastated Puerto Rico in 2017, and Hurricane Florence, a powerful category 4 storm that smashed into the US east coast a year later.
“While the attribution of individual tropical cyclone events remains difficult, there can be no doubt that climate change is creating more intense storms,” said Peter Pfleiderer, a scientist at the Berlin-based Climate Analytics, who led the study.
“Our results do not imply that increasing sea-surface temperatures lead to more tropical cyclones – but point towards a trend of more intense storms and therefore more extreme outcomes for seasons with many tropical cyclones.”
Separate research released this week found that climate breakdown is increasing the amount of rainfall that occurs during a major storm, as well as helping intensify the storm itself.
An analysis of the 2020 hurricane season, when a record 30 named storms stirred from the Atlantic, found that global heating heightened extreme rainfall over three-hour periods by 11% compared with what would be expected in pre-industrial times.
The study, which “hindcasted” the 2020 hurricane season with a computer model that showed what would have happened if climate change were not occurring, found that coastal communities are now at greater risk from deadly flooding from thunderous bursts of storm rainfall.
This sort of intensification caused more than 20 people to die from flooding, many of them while trapped in basement apartments, in New York and New Jersey in October when the remnants of Hurricane Ida, which had already ravaged New Orleans, still had the strength to travel across a broad sweep of the eastern US.
“You get a bigger climate signal with the more intense storms. With stronger wind speeds, you get more water evaporation and see this sort of flooding,” said Kevin Reed, a climate scientist at Stony Brook University who led the research, published in Nature Communications.
“Climate change is often thought of as a distant problem but the reality is that climate change is here, our climate has changed and one of the clearest ways we can see that is through changes in extreme weather, such as hurricanes.
“As the world continues to warm, storms are going to get rainier and rainier. We are really going to have to get our act together in dealing with this.”
This year’s Atlantic hurricane season, which is expected to be more active than usual, starts on 1 June and runs until 30 November.