Author and climate scientist Bill Pekny says the 2021 hurricane season began early this year, and the forecast is to be active all season long. He explains how this compares to previous seasons, why it is the way it is…and why we shouldn’t assume hurricanes are worsening.
The 2021 hurricane season is upon us again. And according to Bill Pekny—who has an extensive background of tracking hurricanes and studying science—says it’s living up to its preseason prediction of being an active, but not unprecedented, year.
“These days there is a lot of unwarranted fear that these types of storms are getting more frequent and more severe,” says Pekny, author of A Tale of Two Climates: One Real, One Imaginary (Two Climates LLC, 2021, ISBN: 978-1-73493-960-6, $34.59). “This is a misconception driven by the fact that we measure storms in terms of economic damage.”
“We continue to build more and more high-dollar homes, hotels, and resorts in high-risk coastal areas,” he explains. “When hurricanes do make landfall, they naturally create more property damage with higher price tags. In other words, the real culprit is more development, not more hurricanes. People just conflate these two issues.”
He says the experimental reality is that hurricanes in the North Atlantic basin, which includes the Caribbean and Gulf of Mexico areas, are not trending worse in either frequency or intensity over “climatological” (30 year) time scales. The same is true on a global scale. Even the U.S. Environmental Protection Agency (EPA) concluded, “Hurricanes have not become more numerous in recent years.” And, the U.N. Intergovernmental Panel on Climate Change (IPCC) data shows there has been “no increasing trend in tropical cyclone or hurricane numbers.”
Pekny says storms have intrigued him all his life. (“As a young scientist back in 1969, I had the truly unique experience of flying into the teeth of one as a RADAR meteorologist/crewmember with the renowned U.S. Navy Hurricane Hunters,” he notes.) What he’s learned is that, despite great strides in the technology that allows us to track and measure storms, not much has changed with respect to the storms themselves.
Still, from the much shorter-term “weather” perspective, this looks to be an active hurricane season in the North Atlantic basin, says Pekny. Here is his latest check on tropical cyclone activity this season in the northern hemisphere as of July 19, 2021:
Pekny’s analysis of hurricane season
Basin – Named Storms – Names Storm Days – Hurricanes – Hurricane Days – Major Hurricanes – Major Hurricane Days – Accumulated Cyclone Energy (ACE)
N Atlantic (Includes Caribbean & Gulf of Mexico) – 5 – 13.75 – 1 – 1.50 – 0 – 0.00 – 12.8
NE Pacific (out to Hawaii) – 7 – 20.00 – 2 – 6.75 – 1 – 2.75 – 34.9
NW Pacific – 3 – 8.50 – 1 – 1.00 – 0 – 0.00 – 7.0
N Indian – 2 – 6.00 – 2 – 3.25 – 1 – 1.50 – 13.8
Total – 17 – 48.25 – 6 – 12.50 – 2 – 4.25 – 68.5
Source: Colorado State University, Department of Atmospheric Science, Tropical Meteorology Project
It’s been a fairly active hurricane season to date, at least with regard to the number of named storms (17 this year, as compared to the historical average of 14.1, at one-fourth of the way through the six-month hurricane season).
In terms of another cyclone metric—Named Storm Days—there’s been a noticeable increase in the number of short-duration tropical storms (those lasting less than two days). Meanwhile, storms lasting longer than two days have not shown a noticeable increase. The long-lasting storms are the most devastating ones.
Another metric around intensity/severity is Accumulated Cyclone Energy, or ACE. It is a measure of the kinetic energy of hurricanes, and is directly tied to sustained hurricane windspeed. Over the long haul, ACE has been trending downward, and it’s no different this year—relatively calm in terms of kinetic energy.
Only one tropical storm in the North Atlantic basin, and not even a hurricane-level storm at that, has made a meaningful landfall this season. It was Tropical Storm Elsa, which earlier this month dumped a significant amount of rain as it passed northeasterly over Florida and then up the Atlantic seaboard before dying out.
What determines how active this hurricane season will be?
Common ingredients in the recipe for hurricane development are a combination of a weather disturbance and thunderstorm activity as seeds for a tropical storm; warm ocean water to power the storm; and low vertical wind shear to prevent the storm from breaking up as it traverses the ocean. Those conditions, and especially the expected continuance of low vertical wind shear in the North Atlantic basin, favor hurricane development throughout this season.
In other words… “Be prepared for another active hurricane season, just like last year,” says Pekny.
About the Author:
Bill Pekny is the author of A Tale of Two Climates: One Real, One Imaginary. He holds physics M.S. and B.S. degrees from Georgia Tech and DePaul University, plus graduate study in physical meteorology and numerical analysis at Florida State University and the University of Utah, and a visiting scholar appointment at the Ginzton Laboratory of Applied Physics at Stanford University.
Bill’s career in science spans over 50 years in the U.S. Armed Forces and the aerospace industry.
His career highlights include: Project Stormfury with the U.S. Navy Hurricane Hunters; applied atmospheric physics and meteorology research; LASER RADAR development; new product testing in various atmospheric environments; aviation optics and electronics; global climate research; and more.
For more information, please visit: Two Climates.
About the Book:
A Tale of Two Climates: One Real, One Imaginary (Two Climates LLC, 2021, ISBN: 978-1-73493-960-6, $34.59) is available from major online booksellers.