Climate Change Fuels More Intense Rainfall and Typhoons

Climate change is altering rainfall patterns globally, with scientists reporting increased variability in precipitation and more intense tropical storms. This shift could be contributing to the severity of recent typhoons and other tropical storms.

Impact of Typhoon Gaemi

This week, Typhoon Gaemi, the year’s most powerful storm, hit Taiwan, the Philippines, and China. The typhoon brought wind speeds up to 227 kph (141 mph), causing widespread closures of schools, businesses, and financial markets. In China, hundreds of thousands were evacuated from the eastern coast before the storm made landfall on Thursday.

Research Findings on Rainfall Patterns

A study led by Zhang Wenxia from the China Academy of Sciences analysed historical meteorological data. The study found that approximately 75% of the world’s land area has experienced increased “precipitation variability,” marked by more significant shifts between wet and dry weather periods.

Warming temperatures enhance the atmosphere’s ability to hold moisture, leading to these wider fluctuations in rainfall. This trend is expected to continue as global temperatures rise, increasing the likelihood of both droughts and floods.

Steven Sherwood from the Climate Change Research Centre at the University of New South Wales, who was not part of the study, noted that this increased variability is seen in most regions, including Australia. “Rainier rain periods and drier dry periods” are becoming more common, he said.

Changes in Tropical Storm Behaviour

Scientists also believe climate change is reshaping the nature of tropical storms, including typhoons, making them less frequent but more intense. Higher water vapour in the atmosphere is seen as a primary cause of these extreme weather phenomena.

Typhoon Gaemi, which hit Taiwan on Wednesday, was the strongest to impact the island in eight years. While individual weather events cannot be directly attributed to climate change, models predict that global warming contributes to stronger typhoons.

Sachie Kanada, a researcher at Japan’s Nagoya University, explained that warmer sea surface temperatures create favourable conditions for tropical cyclone development. This trend has been noted in multiple studies and reports.

Declining Number, Increasing Intensity of Typhoons

China’s recent “blue paper” on climate change reported a significant decline in the number of typhoons in the Northwest Pacific and South China Sea since the 1990s. However, the intensity of these storms has increased. Similarly, Taiwan’s climate change report from May indicated that climate change is likely to reduce the overall number of typhoons in the region but increase their intensity.

Feng Xiangbo, a tropical cyclone research scientist at the University of Reading, attributed the decrease in typhoon numbers to uneven ocean warming. Temperatures in the western Pacific are rising faster than in the east. He also noted that water vapour capacity in the lower atmosphere increases by 7% for each 1 degree Celsius rise in temperature. This could result in a 40% increase in tropical cyclone rainfall in the United States for each degree of warming.