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Tuesday, September 1, 2009

New Study, Recent Atlantic Hurricane Activity might have been Highest in 1,000 Years

New research on the history of tropical cyclone activity in the Atlantic has found that the Atlantic tropical cyclone activity, in terms of frequency and strength over recent decades, may have been greater than any period going back a thousand years.


Reply: No doubt, the 1990s and a good chunk of this decade have been active, but the most active in 1,000 years? For instance, is the author overlooking the active period from the 1930s through the 1950s?


The link below (Thanks Mark B.) to this graph says he is not, but is it an accurate representation?


http://www.nature.com/nature/journal/v460/n7257/fig_tab/nature08219_F3.html#figure-title

Evidence from sediment samples from landfalling hurricanes going back 1,500 years indicated that there was a period of enhanced Atlantic tropical cyclone activity between AD 900 and 1100 followed by a lull. That medieval period of enhancement was perhaps even more active than what we have seen over the past couple of decades.


"We are at levels now that are about as high as anything we have seen in the past 1,000 years," said Michael Mann, director of the Earth System Science Center at Pennsylvania State University and the lead author of the paper.


"Hurricane activity since the mid-1990s is the highest in the historical record, but that only goes back a little more than a century and is most accurate since the advent of air travel and satellites in recent decades," said Mann. "It is therefore difficult to assess if the recent increase in hurricane activity is in fact unusual."


According to the EurekAlert release, the study also adds validity to the theory that two factors fuel higher hurricane activity, namely the La Nina effect and high surface temperatures over the ocean. If climate change continues to warm ocean waters, Mann said, it could lead to more active hurricane seasons.


You can read a more detailed look at the study right here.


The National Science Foundation (NSF) also interviewed Dr. Mann about the results of this study. You can watch that video here.

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Our own Hurricane expert Joe Bastardi disagrees with Mann on this...........

What is it with Dr. Michael Mann? His latest "findings" on hurricanes , that we are at some mythical high is nonsense. And if he understood how the energy budget actually worked, he should be making the argument that the low we are in is more of support of his argument of warming... fake as it is, as it would mean a distortion of the energy budget of the earth because of warming in coldest places. Again using the absolute temp of the earth is not the way to look at this, its to look at the measure of energy of the earth, and understanding that a 1 degree drop where the wet bulb is 80 is equal in energy consideration to a 32 degree rise where its -30 degrees.


So Dr Mann, you should be using the record LOW ACTIVITY for your argument, except that of course would run into the true argument as to what cyclones represent..energy, in which case it falls apart.

http://www.coaps.fsu.edu/~maue/tropical/global_running_ace2.jpg

(From his Accuweather.com Professional column)

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Chris Landsea via the Houston Chronicle......

"The paper comes to very erroneous conclusions because of using improper data and illogical techniques," said Chris Landsea, science and operations officer at the National Hurricane Center.


In his criticism, Landsea notes that the paper begins by saying that Atlantic tropical activity has "reached anomalous levels over the past decade."


This ignores recent work by Landsea and a number of other hurricane scientists who found that storm counts in the early 1900's -- in an era without satellites and fewer seaborne observers -- likely missed three or four storms a year. The addition of these storms to the historical record, he said, causes the long-term trend over the last century to disappear.


"This isn't a small quibble,"he said. "It's the difference between a massive trend with doubling in the last 100 years, versus no trend."

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