Hurricanes are becoming so strong as a result of the climate crisis that their classification should be expanded to include a “category 6” storm, moving up the scale from the standard 1 to 5, according to a new study.
Over the past decade, five storms would have been classified at this new Category 6 strength, researchers said, which would include all hurricanes with sustained winds of 192 mph or more. Such mega-hurricanes are becoming more likely as a result of global warming, studies have found, due to the warming of the oceans and atmosphere.
Michael Wehner, a scientist at the Lawrence Berkeley National Laboratory in the US, said that “192mph is probably faster than most Ferraris, it’s hard to even imagine”. He proposed the new category 6 with another researcher, James Kossin of the University of Wisconsin-Madison. “To be caught in that kind of hurricane would be bad. Very bad.”
The new study, published in Proceedings of the National Academy of Sciencessuggests an extension to the widely used Saffir-Simpson Hurricane Scalewhich was developed in the early 1970s by Herbert Saffir, a civil engineer, and Robert Simpson, a meteorologist who was the director of the US National Hurricane Center.
The scale classifies any hurricane with a maximum sustained wind speed of 74mph or more as a Category 1 event, with the scale rising the faster the winds. Category 3 and above are considered major hurricanes that include severe damage to property and life, with the strongest, Category 5, including all storms that are 157mph or more.
Category 5 storms have caused spectacular damage in recent years – such as Hurricane Katrina’s devastation of New Orleans in 2005 and Hurricane Maria’s devastating impact on Puerto Rico in 2017 – but the new study argues that there is now a class of even more extreme storms are what it requires its own category.
These include Typhoon Haiyan, which killed more than 6,000 people in the Philippines in 2013, and Hurricane Patricia, which reached a top speed of 215 mph when it formed near Mexico in 2015.
“There haven’t been any in the Atlantic or the Gulf of Mexico, but they have conditions that are conducive to a Category 6, it’s just fortunate there hasn’t been one,” Wehner said. “I hope it won’t happen, but it’s just a roll of the dice. We know that these storms have already become more intense, and will continue to do so.”
While the total number of hurricanes is not increasing as a result of the climate crisis, researchers have found that it is the intensity of major storms has increased significantly during the four-decade satellite record of hurricanes. A superheated ocean provides extra energy to rapidly intensify hurricanes, aided by a warmer, moisture-laden atmosphere.
Wehner said the Saffir-Simpson scale is an imperfect measure of the dangers a hurricane poses to people, which mostly come from heavy rainfall and coastal flooding rather than the strong winds themselves, but that a Category 6 represents the increased risks that through the climate crisis. “Our main goal is to raise awareness that climate change is affecting the most intense storms,” he said.
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The systems used to map the world around us were previously adapted to reflect the rapid changes of the modern era. Australia’s Bureau of Meteorology added a new color – press – to its weather maps to account for ferocious heat, while just last week the US government’s Coral Reef Watch program added three new alert categories to capture the increasing heat stress corals are experiencing.
However, there is no indication that there will soon be hurricanes officially classified as category 6. The US National Hurricane Center did not respond to a request for comment on the new study.
