The rising temperatures over oceans and land are significantly increasing heat and moisture, contributing to rapid intensification of storms and heavy rainfall across the globe.
Typhoon Yagi has devastated Asia while Storm Boris has caused heavy rainfall in various parts of Europe, leading to severe flooding in the Sahel region and Hurricane Helene impacting Florida, making September this year exceptionally wet. However, while scientists can directly link some extreme weather events to human-induced global warming, it is still too early to draw conclusions about this stormy month, according to AFP.
Streets in Glucholazy, Poland, flooded in September 2024. (Photo: Sergei GAPON/AFP).
“Extreme weather events always occur, but their intensity is heightened by global warming, especially in terms of rainfall,” said researcher Paulo Ceppi from the Grantham Institute at Imperial College London. “This could be one of the common drivers of various events occurring in many places around the world.”
Initial signs from monthly data reveal record rainfall in affected areas. In Central Europe, the torrential rains accompanying Storm Boris marked the largest rainfall ever recorded in the region, flooding homes and farms, according to the World Weather Attribution (WWA) network of scientists. Global warming has doubled the chances of prolonged heavy rainfall lasting four days compared to the pre-industrial era, and the damage caused by climate change is accelerating.
Meanwhile, in Wajima, Japan, authorities recorded more than 120 mm of rain per hour from Typhoon Yagi on the morning of September 21, marking the highest rainfall since records began in 1929.
“Attributing different weather patterns around the world occurring simultaneously to climate change is very challenging,” shared Liz Stephens, head of the Red Crescent Climate Center. “But the basic principle remains that for every 1°C of warming, the atmosphere can hold 7% more moisture.”
With global warming projected to exceed 1.5°C above pre-industrial levels, the impacts can be calculated fairly quickly. The summer of 2024 experienced the highest global temperatures ever recorded, surpassing last year’s record, according to the EU’s Copernicus Climate Monitoring program.
This year’s hot summer in the Mediterranean has provided additional evaporative water, leading to more rainfall in Europe under suitable conditions, funneling all that moisture into certain areas, according to Ceppi. Global temperatures, both over oceans and land, have been unusually high in August and September despite La Niña conditions developing in the Pacific, noted researcher Roxy Mathew Koll from the Indian Institute of Tropical Meteorology. The high temperatures support the additional heat and moisture needed for storms to intensify.
La Niña is a natural climate phenomenon that causes cooler ocean surface temperatures in the tropical Pacific, coupled with changes in wind, rainfall, and atmospheric pressure. In many areas, particularly in the tropics, La Niña results in climate impacts that are the opposite of El Niño. El Niño warms ocean surfaces, leading to droughts in some parts of the world and heavy rainfall in others. Currently, a neutral phase is occurring, meaning neither El Niño nor La Niña is present.
