Hurricane expert Dr. Ryan Maue pulls no punches when it comes to putting John Abraham of the Climate Science Rapid Response Team in his place:
Here’s what Abraham has to say at Discovery News:
But wind speeds don’t tell the whole story, said John Abraham, a thermal scientist at the University of St. Thomas in St. Paul, Minn. The size of a storm, the amount of rain it dumps, and the size of the wave surges it produces also determine how damaging a hurricane will be, even though the category scale doesn’t take those details into account.
“The hurricanes that really matter, that cause damage, are increasing,” Abraham said. “What scientists have been saying would happen for decades is now happening. There’s an economic cost to not doing anything about this problem.”
Umm, no, when you look at the frequency and accumulated energy in hurricanes at Dr. Ryan Maue’s Tropical web page, you find it trending down:
Historical Tropical Cyclone Activity Graphics
Figure: Global Hurricane Frequency (all & major) — 12-month running sums. The top time series is the number of global tropical cyclones that reached at least hurricane-force (maximum lifetime wind speed exceeds 64-knots). The bottom time series is the number of global tropical cyclones that reached major hurricane strength (96-knots+). Adapted from Maue (2011) GRL.
Figure: Last 4-decades of Global and Northern Hemisphere Accumulated Cyclone Energy: 24 month running sums. Note that the year indicated represents the value of ACE through the previous 24-months for the Northern Hemisphere (bottom line/gray boxes) and the entire global (top line/blue boxes). The area in between represents the Southern Hemisphere total ACE.
1970- July 2012 monthly ACE Data File (Maue, 2010, 2011 GRL) [--] 1970-2011 global tropical cyclone frequency monthly Data File
Dr. Patrick Michaels points out last Friday in this excellent essay on hurricanes:
It’s been 2,535 days since the last Category 3 storm, Wilma in 2005, hit the beach. That’s the longest period—by far—in the record that goes back to 1900.
Quite a drought. He adds:
Aren’t there more whoppers—the powerful Category 4 and 5 monsters that will mow down pretty much anything in their path? As is the case with much severe weather, we simply see more than we did prior to satellites and (in the case of hurricanes) long-range aircraft reconnaissance. As the National Hurricane Center’s Chris Landsea (with whom I have published on tropical cyclones) has shown, if you assume the technology before satellites, the number of big storms that would be detected now is simply unchanged from the past.
There’s a pretty good example of this spinning in the remote Atlantic right now, which is Hurricane Kirk, far away from shipping channels, land, and nosy airplanes. Kirk is compact enough that it would likely have been completely missed fifty years ago. If it spins up into a Category 4 (which is currently not forecast), that would be another biggie that would have gotten away, back in the day.
There’s another reason that the increase in frequency is more apparent than real: “shorties”. That’s what Landsea calls the ephemeral tropical whirls of little consequence that are now named as storms more because of our detection technology than anything else. There’s also probably an overlay of institutional risk aversion in play, as it is now recognized that seemingly harmless thunderstorm clusters over the ocean can spawn decent floods when they hit land.
There is another driver for an increase in Atlantic hurricane frequency that isn’t operating elsewhere. In 1995, a sudden shift in the distribution of North Atlantic temperatures increased hurricane frequency. Landsea predicted—at the time—that the Atlantic would soon fire up from its hurricane doldrums of the previous two decades, which it did. This type of shift has occurred repeatedly in the last century, both before and during (modest) global warming from greenhouse gases.
The influence of technology on storm reporting is something I’ve talked about in great detail before: