The unrelenting warming of coastal waters in the Pacific Ocean is giving birth to more powerful typhoons that have, during the course of the year, battered China, Japan and the rest of the Asian mainland.
Surprisingly, the Philippines -- the most typhoon-prone country in the world -- has seen an unusual dearth of typhoons so far this year.
Over the past 40 years, however, typhoons that hammered East and Southeast Asia have become stronger and are expected to gain in strength thanks to climate change. The likely cause is warming ocean waters near the coasts, said a new study just published in the journal, Nature Geoscience.
"It is a very, very substantial increase," said Prof. Wei Mei at the University of North Carolina at Chapel Hill, who led the study.
"We believe the results are very important for East Asian countries because of the huge populations in these areas. People should be aware of the increase in typhoon intensity because when they make landfall these can cause much more damage."
The study warns typhoons striking eastern China, Taiwan, Korea and Japan will likely be even stronger and deadlier in the future. That's because ocean surface water is projected to become warmer in the years ahead.
Typhoons are storms that form over the ocean in tropical areas with winds of at least 74 miles per hour. Warming ocean waters intensify typhoons because they provide more heat and more energy to the storm.
Researchers looked at two different data sets to determine the intensity of the tropical storms from 1977 to 2015: the Joint Typhoon Warning Center managed by the US Navy and Air Force and the Japan Meteorological Agency.
They discovered typhoons that struck East and Southeast Asia have intensified by 12 percent to 14 percent.
They also found that the number of category 4 and 5 typhoons (those with wind speeds between 130 mph and 157 mph or higher) increased to some seven per year today from less than five in late 1970s.
Researchers also looked at how ocean water temperatures in the northwest Pacific changed between 1977 and 2013. They discovered the ocean waters off the coasts of East and Southeast Asia became a lot warmer.
In the open ocean where temperatures haven't increased that much, the intensity of typhoons hasn't changed significantly. That means that the stronger storms are probably due to the warming waters that deliver energy into tropical storms.
Wei believes future global warming will heat the oceans in Asia and lead to even more intense typhoons.