New Data Analysis Links Atlantic Ocean Warming to Stronger Hurricanes
28 February 2007
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| Hurricane Katrina. Source: NOAA. |
Atmospheric scientists have uncovered fresh evidence to support the theory that global warming has contributed to the emergence of stronger hurricanes in the Atlantic Ocean. But the trend doesn’t hold up in the world’s other oceans.
Scientists funded by the National Science Foundation (NSF) and affiliated with the University of Wisconsin-Madison and NOAA's National Climatic Data Center (NCDC) in Asheville, N.C., reported the findings in the journal Geophysical Research Letters. The work should help clarify two studies last year that drew connections between global warming and increasingly intense hurricanes.
Documenting trends in hurricane intensity is made more difficult by sparse observations and has led to debates about whether the trends are real, or are artifacts of observations. This study has directly addressed this point by using, for the first time, a new satellite data set to look at hurricane trends.
—Jay Fein, program director in NSF’s division of atmospheric sciences
For decades, hurricane researchers found it difficult to work with the inconsistent nature of hurricane data. Before the advent of weather satellites, scientists were forced to rely on scattered ship reports and sailor logs to stay abreast of storm conditions. The advent of weather satellites during the 1960s dramatically improved the situation, but the technology has changed so rapidly that newer satellite records are barely consistent with older ones.
Working with an NCDC archive that holds global satellite information for the years 1983 through 2005, James Kossin, a scientist at the University of Wisconsin-Madison, and his colleagues evened out the numbers by simplifying newer satellite information to align it with older records.
This new data set is unlike anything that’s been done before. It’s going to serve a purpose as being the only globally consistent data set around. The caveat of course, is that it only goes back to 1983.
—James Kossin
After NCDC researchers recalibrated the hurricane figures, Kossin took a fresh look at how the new numbers on hurricane strength correlate with warming ocean temperatures, a side effect of global warming. What he found both supported and contradicted previous findings.
The data say that the Atlantic has been trending upwards in hurricane intensity quite a bit. But the trends appear to be inflated or spurious everywhere else, meaning that we still can't make any global statements.
—James Kossin
Sea-surface temperatures may be one reason why the Atlantic Ocean is unique, says Kossin.
The average conditions in the Atlantic at any given time are just on the cusp of what it takes for a hurricane to form. So it might be that only a small change in conditions creates a much better chance of having a hurricane.
—James Kossin
The Atlantic is also unique in that the physical variables that converge to form hurricanes—including wind speeds, wind directions and temperatures—mysteriously feed off each other to make conditions ripe for a storm. But scientists don’t understand why, Kossin adds.
While we can see a correlation between global warming and hurricane strength, we still need to understand exactly why the Atlantic is reacting to warmer temperatures in this way, and that is much more difficult to do. We need to be creating models and simulations to understand what is really happening here.
—James Kossin
Resources:
“A globally consistent reanalysis of hurricane variability and trends”; J. P. Kossin, K. R. Knapp, D. J. Vimont, R. J. Murnane, B. A. Harper; Geophysical Research Letters, Vol. 34, L04815, doi:10.1029/2006GL028836, 2007
The authors of the paper published today in Geophysical Research Letters describe their algorithm to homogenize different global satellite hurricane intensity data from 1983 in six regions of Global Ocean and compare their straightened records with previous reconstructions. Full text of the paper could be found here:
http://www.ssec.wisc.edu/~kossin/articles/Kossin_2006GL028836.pdf
Their findings:
“Using a homogenous record, we were not able to corroborate the presence of upward trends in hurricane intensity over the past two decades in any basin other then the Atlantic. Since the Atlantic basin accounts for less then 15% of global hurricane activity, this result poses a challenge to the hypotheses that directly relate globally increasing tropical SST (sea surface temperature) to increases in long-term mean global hurricane intensity”
No analysis was performed to correlate hurricane intensity with sea temperature records, atmosphere temperature, or any other factors.
Wild misinterpretation of the research in NSE press release and popular media already sparked protests:
http://sciencepolicy.colorado.edu/prometheus/archives/science_politics/001131spinning_science.html
Posted by: Andrey | 28 February 2007 at 08:17 PM
Of course, warmer water - hurrican intensity increase.
Now why didn't I think of that?
Posted by: Doodlebugger | 28 February 2007 at 09:01 PM
Dodlebugger:
Paradoxically, some serious researches suggest that it is not the case. Warmer weather results in more moisture in lower atmosphere. More moisture in the air reduces differences in night and day, winter and summer, and any other sharp temperature irregularities, which are the driving force of extreme weather events. Current minuscule increase in Earth temperature does not produce any measurable increase or decrease in extreme weather events, which was demonstrated in this paper with hurricanes. Most of the data suggesting that warmer climate produces less extreme weather events is based on historical records of massive winter storms and summer droughts occurred during Little Ice Age five hundred years ago and two degrees colder. However, no one could prove any significant difference, let alone explain how exactly temperature affects extreme weather.
By the way, it is not hot weather which produces droughts. It is lack of rain which produces hot weather, to put it ultimately simple.
Posted by: Andrey | 28 February 2007 at 09:27 PM
My 2 cents:
Global Warming reinforces the current AMO warm phase.
Posted by: allen_xl_Z | 28 February 2007 at 09:51 PM
Allen:
We will know in a century or two, when reliable observations of Atlantic Multidecadal Oscillation will cover at least couple of full cycles.
Posted by: Andrey | 28 February 2007 at 10:48 PM
Andrey: good catch. I looked at the report yesterday. It does not say what the media is reporting.
Personally I think hurricanes increase in # but not intensity with ocean heat. But that isn't exactly good news or a scientific opinion.
I wish science reporting in the media was better.
Posted by: K | 01 March 2007 at 10:46 AM
From the same paper;
"Still, the very real and dangerous increases in recent
Atlantic hurricane activity will no doubt continue to provide a heightened sense of purpose to research addressing how hurricane behaviour might change in our changing climate,..."
Posted by: Shaun Williams | 01 March 2007 at 12:52 PM
Its common sense that warmer water means easyer hurricane formation. Thus now that warm waters are covering more areas hurricanes are popping up in new places.
Watm water means more powerful hurricanes in that it lets them form and travel while getting stronger over a much wider area AND tyhat hurricanes are less likely to hit a cool patch and weaken.
The REAL danger isnt from more powerful hiricanes its from more of the powerful ones and from popwerful ones where none had been before. Its not an d5 hitting new orleans we have to fear but an f4 hitting new york or la.
Posted by: wintermane | 01 March 2007 at 02:13 PM
Shaun:
I did not want to post this quote, because it is probably (at least it should be) is intimidating to the authors of the research. Practically all scientific papers related to climate HAVE to pay lip service to AGW, even if their actual findings contradict the idea. Other vice – no funding, no publication, and a lot of problems. That’s why some shallow observers claim that 100% of scientists agree with AGW scenario. In reality most published scientific articles or directly contradict AGW scenario, or estimate climate change and human role in it many times less dramatic then reported in IPCC summaries and in the press.
It is very troubling and shameful situation.
Posted by: Andrey | 01 March 2007 at 09:06 PM
Andrey:
What drivel. If nothing else, you're persistent.
Posted by: Shaun Williams | 02 March 2007 at 01:51 AM
Shaun:
I am not an indigenous expert on the subject. I am just trained M.Sc. in mathematics and applied physics (and etc. afterwards) with quarter century experience in environment protection industry and engineering with couple of publications and patents.
I am capable to read scientific articles on the subject and understand what exact results they are claiming. I am not nearly in possession of knowledge to assess the methods they are employing.
But it does not take to be rocket scientist to see that AGW scare is totally unsupported by science and in fact is the most outrageous distortion of the science in modern history.
To quote one senior scientist on the subject, AGW scare is “ENRON case, scientific variety”
P.S. Do not think that your and my comments are indigenous. See for example :
http://www.climateaudit.org/?p=1206#comments
Posted by: Andrey | 02 March 2007 at 04:40 AM
Only a true beleiver like Mr. Gore would actually say that warmer world would promote more evaporation and then dessicate everything.
Newton showed that what goes up, must come down.
Evaporated water must eventually fall as rain; the more evaporation the more rain...Duh...
As to whether there are more hurricanes or more higher powered hurricanes, the history of the last thirty years is exactly anti-correlated to this Gorean thesis. There are fewer hurricanes in number and fewer in high intensity.
Lucky for the warming alarmists that two hurricanes went ashore aimed at major metropolitan human habitations in the past 15 years. Else the wouof have little to say.
Did you know that last season there was but one hurricane to hit North America in the Atlantic, when on average there should have been about a dozen.
The honest reality is that changes in temperature by a fraction of a degree is too small to be accurately measurable, and too small to have an appreciable effect.
Too bad for Gore's Green Shirts that they can't burn all the scientific writings and books they don't like, and muzzle or intimidate all the scientists like Hitler's Brown Shirts did in the 30s.
But they are certainly trying...
Posted by: Stan Peterson | 03 March 2007 at 10:40 PM
As someone living the South Pacific, I'm happy to hear the news, I hope it pans out that way. Perhaps now I'll only have to worry about rising sea levels, coral bleaching, and ocean acidification. We already have tropical diseases.
But wow, it only took twelve comments for a distinguish gentleman to compare Al Gore to Hilter. Funny that, I didn't think Gore was an author of the paper under consideration. Oh, it must be Gore tried to suppress it, right, there's the connection.
Posted by: Tavita | 04 March 2007 at 10:13 PM