It's been awhile since we've talked about science ...hurricane season runs from June to November in United States
Now, there may be a category 6 added. Read on to find out more.
Category 1 hurricanes have wind speeds between 74 and 95 mph, while Category 5 hurricanes have wind speeds of 158 mph or more. The Saffir-Simpson Windscale has been used by the National Hurricane Center to communicate the risk of property destruction for over 50 years. Scientists concerned about global warming have questioned whether the vague Category 5 adequately describes the potential for hurricane destruction in an era of rising sea temperatures, which are making storms more powerful and destructive.
Because hurricanes are becoming more powerful and destructive due to rising ocean temperatures, climate scientists Michael Wehner from Berkeley Lab and James Kossin from the First Street Foundation questioned whether the vague Category 5 adequately conveys the danger of hurricane damage in a warming world. They researched and documented their findings in a recent publication in the PNAS, where they also proposed an additional category to the Saffir-Simpson Wind Scale—Category 6—to include storms with wind speeds exceeding 192 mph.
"Our motivation is to reconsider how the open-endedness of the Saffir-Simpson Scale can lead to underestimation of risk, and, in particular, how this underestimation becomes increasingly problematic in a warming world," said Wehner, who has spent his career studying the behavior of extreme weather events in a changing climate and to what extent human influence has contributed to individual events.
Tropical cyclones, typhoons, and hurricanes are becoming more powerful because of the higher surface ocean and tropospheric air temperatures caused by human-caused global warming, according to Wehner. The group discovered five storms that may have been categorized as Category 6 in their examination of hurricane records from 1980 to 2021. All of these storms happened within the last nine years of records. By analyzing the widening gap in wind speeds between storms of lesser categories, they were able to ascertain a hypothetical top limit for Category 5 hurricanes. Typhoons, tropical storms, and hurricanes all refer to the same kind of weather event; the only difference between the three names is where they form in the ocean: tropical cyclones in the South Pacific and Indian Oceans, typhoons in the Northwest Pacific, and hurricanes in the North Atlantic and Northeast Pacific Oceans. To investigate the potential effects of warmer temperatures on storm intensification, researchers looked at both historical data and computer simulations. According to their models, the likelihood of Category 6 storms in the Gulf of Mexico and Southeast Asia, as well as in the Philippines, increases by 50% and doubles, respectively, for every 2 degrees Celsius over pre-industrial levels of global warming.
"Even under the relatively low global warming targets of the Paris Agreement, which seeks to limit global warming to just 1.5°C above preindustrial temperatures by the end of this century, the increased chances of Category 6 storms are substantial in these simulations," said Wehner. "Tropical cyclone risk messaging is a very active topic, and changes in messaging are necessary to better inform the public about inland flooding and storm surge, phenomena that a wind-based scale is only tangentially relevant to. While adding a 6th category to the Saffir-Simpson Hurricane Wind Scale would not solve that issue, it could raise awareness about the perils of the increased risk of major hurricanes due to global warming," said Kossin. "Our results are not meant to propose changes to this scale, 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."
Source:
DOE/Lawrence Berkeley National Laboratory. "In a warming world, climate scientists consider category 6 hurricanes." ScienceDaily. ScienceDaily, 5 February 2024. <www.sciencedaily.com/releases/2024/02/240205164816.htm>.
WNCTimes February 2024