Reposting this piece in light of Michael Mann’s commentary on the research mentioned here.
Michael Mann PhD in Proceedings of the National Academy of Science:
For a number of years, I have argued that we are now, thanks to the effects of human-caused warming, experiencing a new class of monster storms—”category 6” hurricanes. That is to say, we are witnessing hurricanes that—by any logical extension of the existing Saffir-Simpson scale—deserve to be placed in a whole separate, more destructive category from the traditionally defined (category 5) “strongest” storms. Up until now, that was really just a matter of opinion (1). There was no peer-reviewed research to justify the assertion. Now there is, with a new article by Wehner and Kossin in PNAS (2) that lays out a rigorous, objective case for expanding the scale to accommodate climate change-fueled tropical cyclones that are qualitatively stronger and more destructive than conventionally defined category 5 storms.
“Unprecedented Ferocity”.
When a Tropical Cyclone comes at you like a Velociraptor.
Hurricanes are getting so strong in a warming world that a Category 6 intensity should be added to the Saffir-Simpson Hurricane Wind scale, a new study finds.
Why it matters: The research shows how significantly climate change is altering storm intensity and other characteristics, as well as further underscoring the limitations of the scale.
Reality check: The paper, published Monday in the journal Proceedings of the National Academy of Sciences, does not represent an official move by the National Hurricane Center to add another hurricane category.
- Instead, it offers scientific reasons for the new category to be considered.
- The researchers note that the top hurricane category — Category 5 — has no upper bound, despite the fact that the damage potential from such a storm’s maximum sustained winds increases exponentially.
The intrigue: The study comes as scientists are having to add new classifications and colors to marine heat stress maps, and alter axes on charts of ocean heat content and other climate variables as rapid, human-caused climate change brings large shifts around the globe.
- Last year was the warmest since instrument records began and very likely the hottest in at least 125,000 years.
- This year is expected to come near to or beat the record set in 2023.
- Early data shows January was likely the 9th-straight-hottest month.
Zoom in: Climate change increases ocean and air temperatures, along with atmospheric water vapor.
- Tropical cyclones tap into the energy from these sources to form and intensify.
- The greater amount of hurricane fuel in a warming world is already causing these storms to change in multiple ways that can make them more destructive, the study shows, relying on growing scientific evidence.
Over the past decade, five storms would have been classed at this new category 6 strength, researchers said, which would include all hurricanes with sustained winds of 192mph or more. Such mega-hurricanes are becoming more likely due to global heating, 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 has proposed the new category 6 alongside another researcher, James Kossin of the University of Wisconsin-Madison. “Being caught in that sort of hurricane would be bad. Very bad.”
The new study, published in Proceedings of the National Academy of Sciences, proposes an extension to the widely used Saffir-Simpson hurricane scale, which 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 sustained maximum wind speed of 74mph or more to be a category 1 event, with the scale rising the faster the winds. Category 3 and above is considered to include major hurricanes that risk 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 ravaging of New Orleans in 2005 and Hurricane Maria’s devastating impact upon Puerto Rico in 2017 – but the new study argues there is now a class of even more extreme storms that demands its own category.
They include Typhoon Haiyan, which killed more than 6,000 people in the Philippines in 2013, and Hurricane Patricia, which reached a top speed of 215mph when it formed near Mexico in 2015.
“There haven’t been any in the Atlantic or the Gulf of Mexico yet but they have conditions conducive to a category 6, it’s just luck that there hasn’t been one yet,” said Wehner. “I hope it won’t happen, but it’s just a roll of the dice. We know that these storms have already gotten more intense, and will continue to do so.”
WFLA – Tampa:
WFLA’s Chief Meteorologist and Climate Specialist, Jeff Berardelli, spoke with Wehner over email Monday to discuss the risk to populations along the Gulf of Mexico Coast. Alarmingly, Wehner explained that from his potential intensity analysis, the Gulf of Mexico has the greatest risk of being hit by one of these potential Category 6 storms in the Atlantic Basin.
“The potential for a Cat 6 storm is already there in the Gulf of Mexico and the Caribbean. And any intense storm in the Gulf will make landfall somewhere,” Wehner said. “So your viewers and followers should be aware that climate change has already increased the risk of intense hurricanes in the Gulf and that risk includes storms of unprecedented ferocity.”