Recently, with much media fanfare, some scientists proposed adding a new, upper category to the hurricane rating scale, Category 6, to reinforce the dangers posed by climate change, which they believe is making hurricanes more powerful.
Upon hearing this, my initial reaction was to think of the scene in the classic, faux documentary movie, “This is Spinal Tap,” in which the guitarist tries to explain that his amp is special because it goes to 11. When the director asks the musician, “why don’t you just make 10 a little louder,” the musician/character looks at him befuddled and says, “these go to 11.” Adding a new category to hurricanes is nothing but a way to promote climate alarmism, a method which I think will fail.
There has never been a hurricane in the Atlantic basin that has exceeded 190 mph sustained winds. By the way, sustained winds indicate wind speeds averaged over as little as a single minute — I can hold my breath under water for longer than that. Regardless, no hurricane in the Atlantic basin or almost any other basin has exceeded the newly proposed standard, so it would be hard, based on that standard, to claim hurricanes are getting stronger.
The tropical cyclones mentioned in the report as exceeding 192 mph all occurred several years ago. However, despite increased CO2 and slightly warmer temperatures over the past few years, they have not become the norm or occurred since then. There is at least some anecdotal evidence, based on reports and damage done, that hurricanes may have even exceeded 200 mph in the past, but this was long before accurate measurements could be taken.
What we can say with some certainty is that there is no trend of more frequent or more severe tropical cyclones forming globally or in any hurricane basin, which would implicate long-term climate change. Indeed, multiple studies I cited in an article in 2022 showed that there has likely been a long-term decline in the number of hurricanes across all the different hurricane basins, and there has been no increase in more powerful storms.
Accumulated Cyclone Energy, which measures sustained wind speeds over six hours, has shown no trend in increasing intensity or strength since 1980.
Another measure of tropical cyclone/hurricane strength or intensity is “kinetic energy,” which accounts for the size, maximum wind speeds, and duration of a hurricane. A study published in the journal Geophysical Research Letters concluded climate models project no measurable worsening of future hurricanes if the earth continues to warm.
“Comparing cyclone integrated kinetic energy between present conditions and a projected future climate scenario did not suggest notable changes between the two periods,” wrote the researchers.
One should not be surprised that contrary to climate alarmists’ predictions, hurricane seasons are not becoming worse. Although measured sea surface temperatures have increased, warmer seas are only one factor in hurricane formation, duration, or strength. For instance, research discussed in Science Daily points out that global warming is likely to cause more wind shear in the very areas where hurricanes form and intensify, and wind shear commonly shreds hurricanes. Discussing this point in Climate at a Glance: Hurricanes, meteorologist Anthony Watts writes: “[w]ind shear inhibits strong storms from forming and rips apart storms that have already formed … it is misleading to discuss one factor in hurricane formation (warmer oceans) while failing to discuss an equally important factor (wind shear) that diminishes hurricane formation and intensification.”
There is no evidence that the few hurricanes that have made landfall that would fall under the proposed Category 6 have caused more damage when they struck than Category 5 storms. Importantly, deaths and damage from hurricanes as a percentage of GDP have declined dramatically over the past century’s warming.
If data show hurricanes are not becoming more frequent or powerful, and physics and climate models indicate there is no good reason based in science that they should do so in the future, then one must ask: why the push to add a new upper level category to the long-established hurricane raking system? The only plausible answer I can come up with is to scare people into calling for action to battle climate change.
I doubt it will work. Scientists certainly aren’t speaking with one voice on the issue. Bloomberg is not alone in suggesting such a move may be a bad idea. There is an active Quora debate on the topic, too. Aside from being unnecessary, because few storms will ever attain the level of Category 6, it is unlikely that people stubborn enough to ignore warnings to evacuate when a Category 4 or 5 hurricane is declared will suddenly become fearful once a storm is labeled Category 6. It would be like telling someone, “look this is a bad idea,” and when they ignore the warning, coming back and saying “it’s really, really, super bad, really!” Not very persuasive to most, I suspect.
What it may do, by contrast, is have people who would normally respond to Category 3 or 4 warnings now ignore them thinking, “well how bad can it be, it’s not Category 5 or 6, after all,” a point raised by commentators at Quora.
In the end, complicating the well-known existing hurricane category system that people are familiar with is one climate scare tactic that must be rejected. Adding a new category won’t clarify the dangers of a particular hurricane and may lead to warnings being ignored by more people.
Photo by NASA. Creative Commons Attribution 2.0 Generic.