Rescue teams help residents in boats as they wade through a flooded road after heavy rains brought by Typhoon Gaemi, Marikina City, Philippines, July 24, 2024. | Photo credit: Reuters
An unusual cluster of hurricanes in the Western Pacific and a series of powerful hurricanes in the Atlantic raise questions about the impact of climate change on tropical storms around the globe.
As countries hammered out details of a new climate funding package at the COP29 talks in Azerbaijan, the Philippines was hit by its sixth typhoon in a month while the United States recovered from two devastating typhoons.
Scientists say it’s still unclear how climate change is reshaping the hurricane season, or if it’s responsible for the rare occurrence of four tropical cyclones at the same time in the Western Pacific – the first time that’s happened in November since 1961.
Higher sea surface temperatures accelerate evaporation and provide additional “fuel” for tropical cyclones, increasing rainfall and wind speeds, he said.
And the latest assessment by the Intergovernmental Panel on Climate Change (IPCC), published in 2023, states “high confidence” that global warming will make storms more intense.
The Philippines’ latest typhoon Man-Yi made landfall on Saturday, forcing the evacuation of hundreds of thousands of residents. At least eight people died on Monday, raising the death toll to more than 160 since October.
“It is very rare to see a group of four tropical cyclones in the western North Pacific together,” said Feng Xiangbo, a tropical storm researcher at England’s University of Reading.
“(However) blaming climate change … for this week’s unprecedented events is not straightforward,” he added.
Evidence shows that climate change is increasing the intensity of storms, as well as decreasing their frequency, especially during the late season from October to November, Feng said.
This year, recently active atmospheric waves near the equator could be an alternative explanation for the unusual uptick, Feng said, but the link to climate change is unclear.
The high pressure belt known as the sub-tropical ridge, part of the global atmospheric circulation system, has strengthened and stretched further north and west than usual, according to Choy Chun Win, Senior Scientific Officer at the Hong Kong Observatory.
Those ridges can direct storms westward, diverting them from cold water and wind shear, which would normally do damage, providing an explanation for why the four coexist, he said.
“However, more research is needed to assess the contribution of climate change to the likelihood of tropical cyclone occurrence and a longer tropical cyclone season,” he said.
Ben Clarke, weather researcher at London’s Grantham Institute on Climate Change and Environment, said “it would make sense” that rising sea temperatures would outlast typhoon season, but the evidence is not conclusive.
“There has been a recent clear increase in the number of tropical cyclones affecting the Philippines in the less active season from approximately December to February, but this does not tell us much about … June-November,” he said.
stronger hurricanes
In an analysis published on Wednesday, US weather researcher Climate Central said Atlantic hurricanes have intensified this year as a result of record-breaking ocean warming.
Since 2019, warmer temperatures have boosted average wind speeds to 18 miles per hour (29 kph) and pushed three hurricanes to the top Category 5, the study said.
Two deadly Category 5 hurricanes known as Helene and Milton, which hit Florida in September and October, would have been impossible without climate change, he said.
Research is still being done on whether tropical cyclones are becoming more frequent, but there is high scientific confidence that warmer ocean temperatures are driving more rainfall and causing higher storm surges, said Daniel Gilford, Climate Central’s lead hurricane researcher.
“While other factors contribute to the strength of each storm, the impact of rising sea surface temperatures is important and significant,” he said.
“In the Atlantic, more than 80% of storms since 2019 are clearly influenced by warmer ocean temperatures caused by carbon pollution.”
Published – November 20, 2024 20:35 IST
