Two scientists proposed a shift to the system that categorizes hurricanes as climate change supercharges extreme weather events: The creation of a Category 6 designation to identify the monsters that may come.
In a new paper, Michael Wehner, a senior scientist at the Lawrence Berkeley National Laboratory, and James Kossin, a distinguished science adviser at the First Street Foundation, write that the current system to measure hurricanes presents no upper bound beyond Category 5. In a world where climate change has been linked to stronger storms, the pair found that a sixth level of the Saffir-Simpson Scale could have already been applied to deadly and destructive storms that formed in the Pacific in recent years.
“Our motivation here is to reconsider how the open-endedness of the scale can lead to an underestimation of risk, and, in particular, how this underestimation becomes increasingly problematic in a warming world,” the researchers wrote. “Storm intensities well above the category-5 threshold are being realized, and record wind speeds will likely continue to be broken as the planet continues to warm.”
The paper, published Monday in the journal Proceedings of the National Academy of Sciences, identifies the bounds of what could be a Category 6 hurricane with sustained winds of more than 192 mph.
The scientists found five storms in the last decade that would have exceeded that threshold, two of which hit the Philippines, including the devastating 2013 Typhoon Haiyan.
“Previously, it has been argued that one particularly destructive storm, Typhoon Haiyan, should be included in a proposed category 6,” the authors wrote. “But Haiyan does not appear to be an isolated case.”
There is no formal plan by government forecasters to update the scale used to measure hurricane intensity, and some researchers have warned another level in the scale could diminish the threat the public sees when a storm is designated as an already life-threatening Category 5.
But Axios’ Andrew Freedman notesmeteorologists have long pointed to drawbacks of the current Saffir-Simpson Scale as it mainly focuses on wind, not water in the form of waves or flooding. The paper also notes that most deaths linked to hurricanes in the United States are caused by coastal storm surges and flooding, while wind is only linked to 8% of fatalities.
However, Wehner and Kossin said the paper is meant to present a hypothetical shift that could lead to more discussion about better warning the public when a monster storm is heading its way.
“Our results are not meant to propose changes to this scale,” they write, “but rather to raise awareness that the wind-hazard risk from storms presently designated as category 5 has increased and will continue to increase under climate change.”
