Typhoon intensity in the northwest Pacific Ocean has increased markedly over the last four decades, according to an analysis by a pair of researchers at Scripps Institution of Oceanography at the University of California San Diego and the University of North Carolina.
Wei Mei, a former Scripps postdoctoral scholar, and Shang-Ping Xie, the Roger Revelle Chair in Environmental Science at Scripps, said the most significant aspect of their National Science Foundation-supported analysis is that the strongest intensification has occurred in typhoons that make landfall, which is about half of all typhoons. It is a consequence of strong ocean warming near the coasts of East and Southeast Asia.
“The intensification of landfalling typhoons coincided with rapid economic development in coastal China,” said Mei. “The effects were strongly felt there.”
As an example, Mei noted that Typhoon Nepartak, the first typhoon of the 2016 season, caused the deaths of more than 80 people and nearly 10 billion Chinese yuan (more than US $1.5 billion) in damage in China.
The paper, “Intensification of landfalling typhoons over the northwest Pacific since the late 1970s,” appeared in the Sept. 5 advance online publication of the journal Nature Geoscience.
“Climate models project an increase in the global number of major tropical cyclones (typhoons and hurricanes) as the climate warms but the regional change is hard to predict,” said Xie. “Our results help constrain the prediction of such regional changes.”
The study builds on another paper the researchers published last year that found that the entire Pacific Ocean basin is likely to experience more intense typhoons this century. This study took a regional approach in reviewing observations of annual-mean peak intensity and annual number of strongest typhoons to consider which Pacific typhoons had intensified the most.
Mei said the finding is particularly robust because of the strong agreement between datasets from independent meteorological agencies about the intensity of typhoons over the past 38 years. Records from the Joint Typhoon Warning Center and Japan Meteorological Agency showed that the annual number of category 4 and 5 typhoons – the strongest – has increased by 40 percent and that the proportion of these strong typhoons to the total number of typhoons has more than doubled.
The study predicts that typhoons that strike eastern mainland China, Taiwan, Japan, and Korea will intensify further as human-caused global warming continues. For countries like China that signed on to the Paris agreement, building science-based adaptation strategies is at the forefront of addressing serious climate change impacts in the 21st century.
- Robert Monroe