The World Meteorological Organization (WMO) issued a stunning statement in a recent report. Roger Pielke Jr. has the details on his blog.
Just to remind folks that we’ve been saying much the same thing for months on WUWT:
Global Warming = more hurricanes | Still not happening
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A team of researchers under the auspices of the World Meteorological Organization has published a new review paper in Nature Geoscience (PDF) updating consensus perspectives published in 1998 and 2006. The author team includes prominent scientists from either side of the “hurricane wars” of 2005-2006: Thomas R. Knutson, John L. McBride, Johnny Chan, Kerry Emanuel, Greg Holland, Chris Landsea, Isaac Held, James P. Kossin, A. K. Srivastava and Masato Sugi.
The paper reaches a number of interesting (but for those paying attention, ultimately unsurprising) conclusions. On North Atlantic hurricanes the paper states (emphasis added):
Hurricane counts (with no adjustments for possible missing cases) show a significant increase from the late 1800s to present, but do not have a significant trend from the 1850s or 1860s to present3. Other studies23 infer a substantial low-bias in early Atlantic tropical cyclone intensities (1851–1920), which, if corrected, would further reduce or possibly eliminate long-term increasing trends in basin-wide hurricane counts. Landfalling tropical storm and hurricane activity in the US shows no long-term increase (Fig. 2, orange series)20. Basin-wide major hurricane counts show a significant rising trend, but we judge these basin-wide data as unreliable for climate-trend estimation before aircraft reconnaissance in 1944.
The paper’s conclusions about global trends might raise a few eyebrows.
In terms of global tropical cyclone frequency, it was concluded25 that there was no significant change in global tropical storm or hurricane numbers from 1970 to 2004, nor any significant change in hurricane numbers for any individual basin over that period, except for the Atlantic (discussed above). Landfall in various regions of East Asia26 during the past 60 years, and those in the Philippines27 during the past century, also do not show significant trends.
The paper acknowledges that the detection of a change in tropical cyclone frequency has yet to be achieved:
Thus, considering available observational studies, and after accounting for potential errors arising from past changes in observing capabilities, it remains uncertain whether past changes in tropical cyclone frequency have exceeded the variability expected through natural causes.
The paper states that projections of future activity favor a reduction in storm frequency coupled with and increase in average storm intensity, with large uncertainties:
These include our assessment that tropical cyclone frequency is likely to either decrease or remain essentially the same. Despite this lack of an increase in total storm count, we project that a future increase in the globally averaged frequency of the strongest tropical cyclones is more likely than not — a higher confidence level than possible at our previous assessment6.
Does the science allow detection of such expected changes in tropical cyclone intensity based on historical trends? The authors say no:
The short time period of the data does not allow any definitive statements regarding separation of anthropogenic changes from natural decadal variability or the existence of longer-term trends and possible links to greenhouse warming. Furthermore, intensity changes may result from a systematic change in storm duration, which is another route by which the storm environment can affect intensity that has not been studied extensively.
The intensity changes projected by various modelling studies of the effects of greenhouse-gas-induced warming (Supplementary Table S2) are small in the sense that detection of an intensity change of a magnitude consistent with model projections should be very unlikely at this time37,38, given data limitations and the large interannual variability relative to the projected changes. Uncertain relationships between tropical cyclones and internal climate variability, including factors related to the SST distribution, such as vertical wind shear, also reduce our ability to confidently attribute observed intensity changes to greenhouse warming. The most significant cyclone intensity increases are found for the Atlantic Ocean basin43, but the relative contributions to this increase from multidecadal variability44 (whether internal or aerosol forced) versus greenhouse-forced warming cannot yet be confidently determined.
What about more intense rainfall?
. . . a detectable change in tropical-cyclone-related rainfall has not been established by existing studies.
What about changes in location of storm formation, storm motion, lifetime and surge?
There is no conclusive evidence that any observed changes in tropical cyclone genesis, tracks, duration and surge flooding exceed the variability expected from natural causes.
Bottom line (emphasis added)?
. . . we cannot at this time conclusively identify anthropogenic signals in past tropical cyclone data.
The latest WMO statement should indicate definitively (and once again) that it is scientifically untenable to associate trends (i.e., in the past) in hurricane activity or damage to anthropogenic causes.
Mike D. (21:23:35) :
First you post a link to paper that is crap by circular modeling, without any disclaimer.
I have no real opinion on the paper. Was interested in hearing what all the experts here would have to say. The ‘slander’ must be on your conscience, it ain’t on mine. For example, I would like to see the ‘circular reasoning’ be pointed out. Where [which paragraph] is the C. R.?
Steve Goddard (16:11:40) :
> Hurricanes are caused by differences in energy between the tropics and the poles.
Hurricanes form in the Hadley cell, that’s separated from the polar cell by the mid-latiude cell. They’re really heat engines powered by the difference in temperature between low and high altiudes, and by the amount of evaporation due to the sea level temperature.
Extratropical storms (like nor’easters) are powered by baroclinicity – the temperature difference between north and south adjacent air masses.
> They are nature’s way of blowing off steam from the tropics and transferring it to the poles.
That they do, and at a Southern New England weather conference someone talked about warmer arctics the winter after some big hurricanes brought a lot of heat north.
> It is not coincidental that the 2007 record Arctic melt came after two very active hurricane seasons.
Well, except that wind and ocean currents we responsible for flushing a huge amount of ice out during the 2007 summer. There was more to the ice melt than just hurricanes.
Greg Cavanagh (21:23:32) :
“All of the IPCC case studies are based on the assumption AGW is correct, what are the affects.”
No, it’s worse. Their starting point was ‘AGW is real AND it is a threat to humankind.’
I don’t know if it is relevant but Dr. Pielke also has pointed out that ocean heat content has been flat or declining for several years (IIRC since 2005 or even before). Since Dr. Hansen made in 2005 very specific predictions re: large OHC increases for the past several years that turned out to be spectacularly wrong, it seems that particular AGW hypothesis has been falsified.
Einstein said you only need to falsify a hypothesis once to prove it wrong. I believe Hansen said that OHC gains were the best way to prove AGW.
The author of a new study on the effects of climate change on tropical cyclones says Australia can expect more destructive storms before the end of the century.
That is despite the fact that the review of existing literature and computer modelling predicts a likelihood of fewer tropical cyclones in the same period.
Tom Knutson is the study’s author and a research meteorologist at the National Oceanic and Atmospheric Administration in the United States.
“When we look at the different modelling work, modelling projections on hurricanes in a warmer climate, the thing that stands out is that the models typically are producing fewer tropical cyclones overall globally,” Mr Knutson said.
http://www.weatherzone.com.au/news/cyclones-to-become-fewer-but-fiercer/13912
Mike D. (21:23:35) :
Leif Svalgaard (19:30:32) : Such is the stuff that gets published these days. Of course, the other side says the same about papers to the contrary 🙂
First you post a link to paper that is crap by circular modeling, without any disclaimer.
Then you justify it with strawman slanders.
Come on, Dr. Svalgaard. You can do better than that. We want to respect you. Try to live up to our mutually shared expectations, please.
I think LS is invoking controversy to stimulate response(pavlovian stimuli) ,however as always the discussion of science by ” press release” has limiting qualities and arguments will become circular if perspective is not added to the argument.
The Pliocene is of specific interest ,as the insolation qualities were similar today,the geography was similar (the isthmus of Panama was closed) and CO2 was lower then today,
One of the authors (Federov) calls this the Pliocene Paradox eg
ABSTRACT
During the early Pliocene, 5 to 3 million years ago (Ma), globally averaged
temperatures were significantly higher than they are today even though the
external factors that determine climate were essentially the same. The
appearance of northern continental glaciers, and of cold surface waters in oceanic
upwelling zones in low latitudes signaled the termination of those warm
conditions. This introduced feedbacks involving ice-albedo and tropical oceanatmosphere interactions that amplified obliquity (but not precession) cycles in
equatorial sea surface temperatures, and in global ice volume, with the former
leading the latter by several thousand years. A future melting of northern
glaciers and a deepening of the thermocline could restore the warm conditions of
the early Pliocene.
Even this recent paper cannot elucidate clearly, in Paleoclimate studies Paradox is the rule not the exception.
Ric Werme,
The fact that hurricanes are transferring heat to the Arctic (as you mentioned) is a pretty definitive indication that is where the ultimate delta T resides.
Do you think the Arctic winds in 2007 might have had something to do with the extra heat?
However, occasionally thinly veiled innuendo does slip past The Night Watch. 🙂
[Anthony hasn’t banned innuendo, but does expect civility, however that is a two way street, on the part of the writer AND the reader to keep chips off shoulders – The Night Watch]
Even the bottom line is written in a negative manner which shows they were looking to suport their thesis rather than look at the evidence and then draw conclusions:
“….we cannot at this time conclusively identify anthropogenic signals in past tropical cyclone data.”
They should have positively concluded:
“….we conclusively identify that there are no anthropogenic signals in past tropical cyclone data.”
Leif Svalgaard (21:50:14) :
I have no real opinion on the paper. Was interested in hearing what all the experts here would have to say.
As one of the least expert “experts” I would have to say I don’t think much of the paper you linked. Since AFAIK none of the models has demonstrated anything like predictive skill in the present environment where they have at least a modicum of observational data to calibrate against, it seems to me to be quite a logical stretch to suggest that by pointing them back a few million years, where what passes for conventional knowledge is mostly creative fiction, that that predictive skill would suddenly be manifested. I’m a bit surprised that you don’t have an opinion on it yourself, but I respect your reticence.
I do think that Mike D. misinterpreted your neutrality, but that’s something you’ve had plenty of experience with around here. I personally think that little of the climate science on either side rises to the level of probative evidence and that most of it offers, at best, hints, indications and reasons for suspicion.
For those who haven’t seen it yet, here’s a link to the Borenstein piece:
http://abcnews.go.com/Technology/wireStory?id=9901992
More to the point, WUWT provides far more in depth and “in context” quotes from the report than does the AP article. Given Borenstein’s predilection for alarmism in the past and AP’s definite bias, I’m inclined to discount their interpretation and go with WUWT.
Ultimately, one needs to read the actual report, not just the abstract, and draw one’s own conclusions. Failing that, go with the analysis that provides the most “in context” quotes from the report.
My own reading of the report (hey, I splurged a little and spent the $32) is that it most certainly is not an endorsement of any Chicken Little alarmist nonsense such as appeared on the Goracle’s web site, however otherwise flawed it may be.
What a Bull paper: since the recent past does not validate their claim and not after these people have fought against the evidence presented by Pielke Jr for instance, these “scientists” are now become pithies and move their claims to the future!
Oh and I forgot to mention our AP warming resident Seth Borenstein jumping on this like a flee on a new rug!
“Steve Koch (22:21:57) :
[…]
Einstein said you only need to falsify a hypothesis once to prove it wrong.”
Those were those old, weak hypothesises. We have stronger, bigger hypothesises now that you have to falsify again and again and they will still stomp all over your city.
Guys, there is no fun, profit or glory in baiting Dr. Leif. When he really has something to say he can be voluble. When he goes all cryptic he’s mainly indulging his sense of humor. In either event he’s got an awesome array of facts and figures at his fingertips and you could find yourself wriggling at the end of his line. Some people fish for pleasure, others …
Dave Wendt (23:07:59) :
I’m a bit surprised that you don’t have an opinion on it yourself, but I respect your reticence.
I don’t know enough about their models to judge. The general dismissal of the type “we cannot predict the weather next week, so predicting the climate 100 years out is meaningless” may miss the fact that weather and climate operate on different scales, spatial and temporal. The larger-scale variations may smooth out a lot of the small-cale turbulence: it is not every butterfly batting its wings that causes a cyclone somewhere else later.
We have a similar situation in solar physics where we cannot predict the precise appearance in space and time of the next sunspot, but we can with confidence predict the solar luminosity a billion years hence.
Glad to see Chris Landsea is now allowed to get on with his work free of politics.
http://www.climatechangefacts.info/ClimateChangeDocuments/LandseaResignationLetterFromIPCC.htm
Leif Svalgaard (01:25:40) :
That doesn’t make any sense, so weather occupies space and climate time? Can you explain how imperfect computer code can give an accurate answer by running the code for a longer time?
A butterfly battings its wings emulated in computer code does nothing more than what the code will allow. It can do whatever you want it to do.
It has not been proven you can predict the luminosity a billion years hence because this has not been verified.
This makes Judith Curry look completely stupid.
Here is a summary of the testimony she gave to Congress in April 2007.
“As the climate continues to warm, models and observations agree that it is
likely that global hurricane intensity will increase and that the number of North Atlantic hurricanes will increase, although the magnitude of the increase is uncertain. The increasing hurricane activity coupled with existing (and increasing) coastal vulnerabilities indicates an urgent need for adaptation in vulnerable coastal regions, particularly in the North Atlantic where the combination of global warming with the active mode of the Atlantic Multidecadal Oscillation indicates substantially elevated
hurricane activity in the next few decades. Reducing carbon dioxide emissions will help avoid the longer term risks associated with sea level rise and storm surge expected from increasingly intense hurricanes”
Leif,
You say you can predict the sun’s behaviour over billions of years. My climate model tells me that when the sun becomes a red giant, summers in Philadelphia will be quite hot and the Arctic will enter a death spiral.
Now it’s droughts.
A paper by Sheffield et al (2009) in Journal of Climate studied global droughts from 1950-2000 and found no increases in length or severity of droughts. Via World Climate Report
Four of the six continental record breaking droughts occured in the 50’s and the other two in the 80’s.
The IPCC’s technical summary stated clearly that droughts would become more severe and prevalent. Apparently not.
No increase in hurricanes, no increase in droughts on and on it goes. The only increase I detect is in the alarmism borne out of sheer desperation.
[But Al Gore said said on his blog on the 23 February, 2010 that]:
“Fact: Climate change causes more frequent and severe snowstorms
[as well as making snow a thing of the past]
Fact: We can expect more extreme weather
Fact: The world is warming at a quickening pace”
My comment in brackets.
Poptech (04:21:58) :
It has not been proven you can predict the luminosity a billion years hence because this has not been verified.
There are billions of stars that go through their life cycles. By observing many, many of them we can verify that they behave as predicted. It is like we had millions of Earth’s with which to compare our theories. The problem with the Earth is that we have only one, so it hard to figure out what happens. If we have many Earths with different amount of CO2, different TSI history, different cosmic ray flux, etc, it is easier to see what the important drivers are.
Joe Bastardi’s preview of the 2010 Hurricane season hints it will be more active, and likely produce storms that will both enter the Gulf of Mexico and also threaten the East Coast. He bases his forecast on the idea the El Nino will be collapsing, leading to conditions quite unlike last year, when the El Nino was building. Rather than dry air in the hurricane “breeding grounds,” as was the case last year, there will be moist air, and rather than relatively high pressure in those “breeding grounds,” there will be low pressure.
Mr. Bastardi attributes the change in activity to purely natural cycles.
It will be interesting to watch the Alarmists. Having all rushed to hitch their wagon to the less-activity horse, they will all need to swiftly unhitch from the less-activity horse and re-hitch to the more-activity horse.
Of course they will do it. They seem to have no shame in this respect.
Over at the Accuweather Global Warming site there is an interesting study on the current blocking pattern caused by the negative AO, with the somewhat obligatory and tedious connection to warming attached. This is humorous, for I recall a National Geographic article (2000?) which did the exact opposite, connecting the positive AO to warming.
No matter what happens, it will be attributed to warming.
Leif Svalgaard (01:25:40) :
“I don’t know enough about their models to judge. The general dismissal of the type “we cannot predict the weather next week, so predicting the climate 100 years out is meaningless” may miss the fact that weather and climate operate on different scales, spatial and temporal. The larger-scale variations may smooth out a lot of the small-cale turbulence: it is not every butterfly batting its wings that causes a cyclone somewhere else later.”
Plenty of contention about this, Leif, amongst climatologists. A different view from Roy Spencer March 2009:-
“Global warming forecasting, in contrast, has been claimed to be possible because we are instead dealing with a small change in the rules by which the atmosphere operates. The extra carbon dioxide we are putting into the atmosphere, it is argued, changes the Earth’s greenhouse effect slightly, which is then expected to change average weather (climate) to a lesser or greater extent. Mathematically speaking, this is referred to as a change in boundary conditions.
But upon closer examination, I have come to realize that the two kinds of variability – weather and climate – maybe are not so different after all. The only major difference between the two is just one of time scale.
The weather today is impacted by what has happened on the Earth, in the atmosphere and on the surface, every day previous to today. In a very real sense, today’s weather retains a memory of all weather which has occurred in the past.
But climate variability is really no different. This year’s climate is a natural result of average weather and climate in previous years. For instance, the slow overturning of the ocean can bring water to the surface which hasn’t been in contact with the atmosphere for maybe hundreds of years. Therefore, the climate we are experiencing today can be related to average weather conditions which occurred hundreds of years ago.”
Full article here:-
http://www.drroyspencer.com/2009/03/