Steve McIntyre at Climate Audit has a very interesting discussion on the giving of credit.

Update: Roger Pielke Jr. blogs on this in rather frank terms:

The short story is that a professor from Ohio State found an error in a paper on Antarctic temperature trends in Nature. He published his analysis of the error on the blog Climate Audit and sent a gracious note to the authors letting them know of his discovery.

What did the authors do? They turned around and submitted the correction to Nature as their own work, and then had it published under their own names without so much as an acknowledgment to the Ohio State professor who actually did the work and made the discovery of the error.

In 2007 Michael Mann and colleagues published a paper (PDF) critical of work suggesting an undercount in storms from historical records, claiming that it was "perilous" to assume that there is a "fixed" relationship between landfalling and total hurricanes in the Atlantic basin:

Of course, estimation of undercount based on the assumption of a fixed relationship between total TC counts and the number of landfalling storms is perilous. Such an approach assumes, in particular, that the large-scale atmospheric steering which determines the trajectories of TCs once they've formed is constant, when there is in fact strong evidence that it is highly variable over time . . .

Now Mann and another set of colleagues (PDF) make what appears to be the exact opposite assumption in a paper just out in Nature, that landfalls are "in rough proportion" to overall basin activity:

We compared the sediment-based record against the above statistical estimate of basin-wide tropical cyclone activity (Fig. 3), guided by a working assumption that an appropriately weighted composite of regional landfalling hurricane activity varies, at multidecadal and longer timescales, in rough proportion to basin-wide tropical cyclone activity.

UPDATE: I still find this hard to believe, is it possible that Mann has mislabeled his data files such that the smoothed data appears in the annual predictions column in his data file, rather than the raw counts? I find it hard believe that it is otherwise the case.

I was curious how the curve shown in Mann et al. discussed earlier today would look using adjusted data, and thanks to Michael Mann the data is up online allowing a comparison with data adjusted according to work in 2007 by Landsea (i.e., it doesn't include the analysis from Landsea et al. released this week).

I graphed (above) the adjusted data (red curve) along with Mann et al.'s "predicted" historical data (blue curve, based on the Landsea data) both unsmoothed, just to see what it looks like -- using information from these files at Mann's directory:

The now iconic image of murky dust rising from a smokestack in the shape of a hurricane on the cover of Al Gore's global warming documentary draws a distinct correlation between rising temperatures and stronger storm patterns.

But here's an inconvenient truth: This year's hurricane season has gotten off to the slowest start in 17 years. And yet global warming alarmists continue to ring their doomsday sirens.

The official start of the hurricane season is June 1. And not since 1992 - the year of Hurricane Andrew - has the Atlantic Ocean been silent past Aug. 4. Meteorologists have yet to name even a single tropical storm in the Atlantic in 2009.

So is global warming really doing anything?

"While it is commonly thought that global warming would increase hurricane activity, that is far from a settled issue," said Rob Eisenson, a meteorologist at Western Connecticut State University. "There are some research studies that suggest global warming would not have that effect."

While NOAA is lowering forecasts, the Accumulated Cyclone Energy (ACE) from FSU COAPS is also quite low. Ryan Maue's Tropical web page at Florida State University has this graph that shows accumulated cyclone energy (ACE) :

Sorted monthly data: Text File Note where 2009 is in the scheme of things. More here.

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Dear Michael and tropical storm folks,

I have some additional concerns about this new paper. As you know, I was one of the reviewers for your Nature paper and, as usual, I "signed" my review. Unfortunately, some very large concerns of mine about the paper were not addressed. The two gravest issues are the paper's use of the Atlantic basin tropical storm frequency data without consideration of new studies and the merger of the paleo-tempestology record to the historical storm data. Perhaps these could be addressed here.

The first point is that the paper disregarded (and not even discussed) crucial new work by Vecchi and Knutson (Journal of Climate, 2008) and Landsea, Vecchi, Bengtsson and Knutson (Journal of Climate, 2009). The first paper showed that about 3-4 tropical storms per year were likely "missed" in the late 19th Century down to less than 1 per year by the 1960s. The second paper (provided to you all in the review process as an accepted paper) shows that two-thirds of the massive doubling trend is simply due to very short-lived (< 2 days duration) tropical storms.

Taking out these "shorties" (very likely due just to our vastly improved observational capabilities) from the record and adding in the estimated number of "missed" medium to long-lived tropical storms causes the long-term trend to completely disappear.

Just when you think it couldn't get any more bizarre in Mann-world, out comes a new paper in Nature hawking hurricane frequency by proxy analysis. I guess Dr. Mann missed seeing the work of National Hurricane Center's lead scientist, Chris Landsea which we highlighted a couple of days ago on WUWT: NOAA: More tropical storms counted due to better observational tools, wider reporting. Greenhouse warming not involved.

Mann is using "overwash" silt and sand as his new proxy. Chris Landsea disagrees in the Houston Chronicle interview saying: "The paper comes to very erroneous conclusions because of using improper data and illogical techniques,"

From the BBC and the Houston Chronicle, some excerpts are below.

Nature has published another remarkable example of academic check kiting by Michael Mann et al, this time "Atlantic hurricanes and climate over the past 1,500 years". (Prior examples of academic check kiting discussed at CA are Ammann and Wahl, the story of which is well told by Bishop Hill's Caspar and the Jesus Paper and "Mann, Bradley and Hughes 2004", cited in Jones and Mann 2004.)

Mann et al 2009 reconstructs Atlantic tropical cyclone counts resulting in a curve that looks pretty much like every other Mannian curve. Atlantic tropical cyclone counts as a linear combination of reconstructed Atlantic SST in the east tropical Atlantic "main development region" (MDR), reconstructed El Nino and reconstructed North Atlantic Oscillation, using a formula developed in (3,16) - which surprisingly enough turn out to be articles by Mann himself (Mann and Sabatelli, 2007; Sabatelli and Mann 2007) previously discussed at Climate Audit here. This is summarized in the article as follows:

An independent estimate of past tropical cyclone activity was obtained using a statistical model for Atlantic tropical cyclone counts. This previously developed and validated 3,16 statistical model conditions annual Atlantic tropical cyclone counts on three key large-scale climate state variables tied to historical variations in Atlantic tropical cyclone counts: (1) the SST over the main development region (MDR) for tropical Atlantic tropical cyclones, which reflects the favourability of the local thermodynamic environment; (2) the El Nino/Southern Oscillation (ENSO), which influences theamount of (unfavourable) vertical wind shear; and (3) the North Atlantic Oscillation (NAO), which affects the tracking of storms, determining how favourable an environment they encounter. The statistical model was driven by proxy-based reconstructions17,18 of these three state variables (Fig. 2), yielding a predicted history of Atlantic tropical cyclone counts for past centuries.

Atlantic hurricanes have developed more frequently during the last decade than at any point in at least 1,000 years, a new analysis of historical storm activity suggests.

The new study, published today in Nature, attempts to reconstruct Atlantic hurricane activity back to the year 500. In doing so the authors found one era, a medieval period around the year 1000, when storm activity matched or exceeded recent hurricane seasons that included storms such as Katrina and Rita.

The scientists used two methods to reconstruct hurricane activity from a period when there were no satellites, reliable ship records or coastal residents taking notes.

One tack is based on the observation that the powerful storm surge of large hurricanes deposits distinct layers of sediment in coastal lakes and marshes. By taking cores of sediments at the bottom of these lakes, which span centuries, scientists believe they can tell when large hurricanes made landfall at a particular location.

The second method used a computer model to simulate storm counts based upon historical Atlantic sea surface temperatures, El Niños and other climate factors.

By Eric Berger
Houston Chronicle
Aug. 12, 2009, 8:34PM

Historical analysis looks for storm activity trends
Atlantic hurricanes have developed more frequently during the last decade than at any point in at least 1,000 years, a new analysis of historical storm activity suggests.

The new study, published today in Nature, attempts to reconstruct Atlantic hurricane activity back to the year 500. In doing so the authors found one era, a medieval period around the year 1000, when storm activity matched or exceeded recent hurricane seasons that included storms such as Katrina and Rita.

The scientists used two methods to reconstruct hurricane activity from a period when there were no satellites, reliable ship records or coastal residents taking notes.

One tack is based on the observation that the powerful storm surge of large hurricanes deposits distinct layers of sediment in coastal lakes and marshes. By taking cores of sediments at the bottom of these lakes, which span centuries, scientists believe they can tell when large hurricanes made landfall at a particular location.

The second method used a computer model to simulate storm counts based upon historical Atlantic sea surface temperatures, El Ninos and other climate factors.

Findings consistent

The two independent estimates of historical storm activity were consistent, said Pennsylvania State University climate scientist Michael Mann, the paper's lead author. Both, for example, pinpointed a period of high activity between 900 and 1100.

"This tells us these reconstructions are very likely meaningful," he said.

This is not Mann's first attempt to use "proxies" for actual observations of conditions to tease out historical climate details. He was among the scientists whose global temperature reconstruction of the last 1,000 years - dubbed the "hockey stick graph" because it showed a distinct upward trend since the mid-19th century attributed to greenhouse gases - received both praise and criticism.

'Erroneous conclusions'

Now he appears to be doing the same with hurricane activity, and the new work is not without its detractors.

"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 1900s - 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."

Limits to usefulness?

Other scientists suggested that the new Nature paper does the best it can in deriving information about historical hurricane activity from a scant amount of data.

Yet this limits how useful the information is, said Rob Korty, an atmospheric scientist at Texas A&M University.

"The bottom line is that I think their work adds new and helpful information," said Korty. "But we must keep in mind the assumptions this kind of work require are large by nature."