Global warming and the frequency of intense Atlantic hurricanes: model results

By: Dr. Jeff Masters , 1:37 PM GMT on April 05, 2010

Share this Blog
7
+

Could global warming increase wind shear over the Atlantic, potentially leading to a decrease in the frequency of Atlantic hurricanes? There is a growing consensus among hurricane scientists that this is indeed quite possible. Two recent studies, by Zhao et al. (2009), "Simulations of Global Hurricane Climatology, Interannual Variability, and Response to Global Warming Using a 50-km Resolution GCM", and by Knutson et al. (2008), "Simulated reduction in Atlantic hurricane frequency under twenty-first-century warming conditions", found that global warming might increase wind shear over the Atlantic by the end of the century, resulting in a decrease in the number of Atlantic hurricanes. For example, the second study took 18 relatively coarse (>60 km grid size) models used to formulate the 2007 IPCC climate report, and "downscaled" them using a higher-resolution (18 km grid size) model called ZETAC that was able to successfully simulate the frequencies of hurricanes over the past 50 years. When the 18 km ZETAC model was driven using the climate conditions we expect in 2100, as output by the 18 IPCC models, the authors found that a reduction of Atlantic tropical storms by 27% and hurricanes by 18% by the end of the century resulted. An important reason that their model predicted a decrease in the frequency of Atlantic hurricanes was due to a predicted increase in wind shear. As I explain in my wind shear tutorial, a large change of wind speed with height over a hurricane creates a shearing force that tends to tear the storm apart. The amount of wind shear is critical in determining whether a hurricane can form or survive.


Figure 1. Top: predicted change by 2100 in wind shear (in meters per second per degree C of warming--multiply by two to get mph) as predicted by summing the predictions of 18 climate models. Bottom: The number of models that predict the effect shown in the top image. The dots show the locations where tropical storms formed between 1981-2005. The box indicates a region of frequent hurricane formation where wind shear is not predicted to change much. Image credit: Geophysical Research Letters, "Increased Tropical Atlantic Wind Shear in Model Projections of Global Warming", by Vecchi and Soden, 2007.

Since the Knutson et al. study using the 18 km resolution ZETAC model was not detailed enough to look at what might happen to major Category 3 and stronger hurricanes, a new study using a higher resolution model was needed. This was done by a team of modelers led by Dr. Morris Bender of NOAA's GFDL laboratory, who published their results in Science in February. The authors used the GFDL hurricane model--the model that has been our best-performing operation hurricane track forecasting model over the past five years--to perform their study. The GFDL hurricane model runs at a resolution of 9 km, which is detailed enough to make accurate simulations of major hurricanes. The researchers did a double downscaling study, where they first took the forecast atmospheric and oceanic conditions at generated by the coarse (>60 km grid) IPCC models, used these data to initialize the finer resolution 18 km ZETAC model, then used the output from the ZETAC model to initialize the high-resolution GFDL hurricane model. The final results of this "double downscaling" study suggest that although the total number of hurricanes is expected to decrease by the end of the century, we should expect an increase of 81% in the number of Category 4 and 5 storms in the Atlantic. This trend should not be clearly detectable until about 60 years from now, given a scenario in which CO2 doubles by 2100. The authors say that their model predicts that there should already have been a 20% increase in the number of Category 4 and 5 storms since the 1940s, given the approximate 0.5°C warming of the tropical Atlantic during that period. This trend is too small to be detectable, given the high natural variability and the difficulty we've had accurately measuring the exact strength of intense hurricanes before the 1980s.The region of the Atlantic expected to see the greatest increase in Category 4 and 5 storms by the year 2100 is over the Bahama Islands (Figure 2), since wind shear is not expected to increase in this region, and sea surface temperatures and atmospheric instability are expected to increase there.

The net effect of a decrease in total number of hurricanes but an increase in the strongest hurricanes should cause an increase in U.S. hurricane damages of about 30% by the end of the century, the authors compute, assuming that hurricane damages behave as they did during the past century. Over the past century, Category 4 and 5 hurricanes made up only 6% of all U.S. landfalls, but accounted for 48% of all U.S. damage (if normalized to account for increases in U.S. population and wealth, Pielke et al., 2008.)


Figure 2. Expected change in Atlantic Category 4 and 5 hurricanes per decade expected by the year 2100, according to the Science paper by Bender et al. (2010).

Commentary
These results seem reasonable, since the models in question have been successfully been able to simulate the behavior of hurricanes over the past 50 years. However, the uncertainties are high and lot more research needs to be done before we can be confident of the results. Not all of the IPCC models predict an increase in wind shear over the tropical Atlantic by 2100, so the increase in Category 4 and 5 hurricanes could be much greater. Also, the GFDL model was observed to under-predict the strength of intense hurricanes in the current climate, so it may not be creating enough Category 4 and 5 hurricanes in the future climate of 2100. On the other hand, IPCC models such as the UKMO-HadCM3 predict a very large increase in wind shear, leading to a drastic reduction in all hurricanes in the Atlantic by 2100, including Category 4 and 5 storms. So Category 4 and 5 hurricane frequency could easily be much greater or much less than the 81% increase by 2100 found by Bender et al.

The estimates of a 30% increase in hurricane damages by 2100 may be considerably too low, since this estimate assumes that sea level rise will continue at the same pace as was observed in the 20th century. Sea level rise has accelerated since the 1990s, and it is likely that this century we will see much more than than the 7 inches of global sea level rise that was observed last century. Higher sea level rise rates will sharply increase the damages due to storm surge, which account for a large amount of the damage from intense Category 4 and 5 hurricanes.

Keep in mind that while a 30% in hurricane damage by the end of the century is significant, this will not be the main reason hurricane damages will increase this century. Hurricane damages are currently doubling every ten years, according to Pielke et al., 2008. This is primarily due to the increasing population along the coast and increased wealth of the population. The authors theorize that the Great Miami Hurricane of 1926, a Category 4 monster that made a direct hit on Miami Beach, would have caused about $150 billion in damage had it hit in 2005. By 2015, the authors expect the same hurricane would do $300 billion in damage. This number would increase to $600 billion by 2025 (though I think it is likely that the recent recession may delay this damage total a few years into the future.) It is essential that we limit coastal development in vulnerable coastal areas, particularly along barrier islands, to reduce some of the astronomical price tags hurricanes are going to be causing. Adoption and enforcement of strict building standards is also a must.

The authors of the GFDL hurricane model study have put together a nice web page with links to the paper and some detailed non-technical explanations of the paper.

References
Bender et al., 2010, "Modeled Impact of Anthropogenic Warming on the Frequency of Intense Atlantic Hurricanes", Science, 22 January 2010: Vol. 327. no. 5964, pp. 454 - 458 DOI: 10.1126/science.1180568.

Vecchi, G.A., B.J. Soden, A.T. Wittenberg, I.M. Held, A. Leetmaa, and M.J. Harrison, 2006, "Weakening of tropical Pacific atmospheric circulation due to anthropogenic forcing", Nature, 441(7089), 73-76.

Vecchi, G.A., and B.J. Soden, 2007, "Increased Tropical Atlantic Wind Shear in Model Projections of Global Warming", Geophysical Research Letters, 34, L08702, doi:10.1029/2006GL028905, 2007.

Jeff Masters

Reader Comments

Comments will take a few seconds to appear.

Post Your Comments

Please sign in to post comments.

or Join

Not only will you be able to leave comments on this blog, but you'll also have the ability to upload and share your photos in our Wunder Photos section.

Display: 0, 50, 100, 200 Sort: Newest First - Order Posted

Viewing: 2005 - 1955

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | 32 | 33 | 34 | 35 | 36 | 37 | 38 | 39 | 40 | 41 | 42 | 43 | 44 | 45 | 46Blog Index

Quoting StSimonsIslandGAGuy:
taz I thought that people with cable or DSL got a new IP every time they logged on.




me tooo i not sure how he got a round i was thinking that the Admin would have block him from makeing a new ID
Member Since: Posts: Comments:
Quoting Cane2010:
T-Dude, I only got as fara s STA2023, what about yourself, my friend? LOL.


oh I'm sure our course numbers are different at Purdue then at your school
Member Since: June 28, 2006 Posts: 25 Comments: 8360
Quoting StSimonsIslandGAGuy:
taz I thought that people with cable or DSL got a new IP every time they logged on.


Not usually, especially if you have a router hooked up and always on. Do an IP check from time to time and you'll see.
Member Since: Posts: Comments:
the Admin has been noted
Member Since: Posts: Comments:
2000. Skyepony (Mod)
There was a few random cloud to ground strikes earlier this evening here way out in front of that line. The excessive lightning may hold together as it crosses central FL.

Explanation of Weather Influence On Methane Buildup At Upper Big Branch Mine

Member Since: Posts: Comments:
thunder's gettin' closer....and the downpour just began
Member Since: Posts: Comments:
am going too e mail the Admin and went him no he bypass yet other banned the next bannned JFV gets will be a IP banned from the blogs all togeter
Member Since: Posts: Comments:
very nice tornadodude
Member Since: Posts: Comments:
Quoting presslord:
Austrailia is such a notorious totalitarian state...


almost as much of one as Cu...
Member Since: June 28, 2006 Posts: 25 Comments: 8360
Austrailia is such a notorious totalitarian state...
Member Since: Posts: Comments:
Quoting PcolaDan:
Okay, what's with the blaming the teachers for not being any good at math??? I'm no good at it either, but have no interest in it either, so I know I didn't work hard at it. It's not for me, no big deal. Why is it the teacher's fault. Did the whole class continuously do bad also? Just wondering. Not being good at math does not mean one is not as smart as they next guy.


my teacher had us play uno in algebra 2... thought it had to do with math..
Member Since: June 28, 2006 Posts: 25 Comments: 8360
Democracy has nothing to do with doing as you please.

from Merriam-Webster

Main Entry: de·moc·ra·cy
Pronunciation: \di-ˈmä-krə-sē\
Function: noun
Inflected Form(s): plural de·moc·ra·cies
Etymology: Middle French democratie, from Late Latin democratia, from Greek dēmokratia, from dēmos + -kratia -cracy
Date: 1576

1 a : government by the people; especially : rule of the majority b : a government in which the supreme power is vested in the people and exercised by them directly or indirectly through a system of representation usually involving periodically held free elections
2 : a political unit that has a democratic government
3 capitalized : the principles and policies of the Democratic party in the United States
4 : the common people especially when constituting the source of political authority
5 : the absence of hereditary or arbitrary class distinctions or privileges
Member Since: Posts: Comments:
1987. Patrap
11:45..dey in da rack snoring easily press,LOL
Member Since: July 3, 2005 Posts: 426 Comments: 128667
tornado warning in Beaufort....the boys and girls on Paris island are gettin' hammered...
Member Since: Posts: Comments:
Okay, what's with the blaming the teachers for not being any good at math??? I'm no good at it either, but have no interest in it either, so I know I didn't work hard at it. It's not for me, no big deal. Why is it the teacher's fault. Did the whole class continuously do bad also? Just wondering. Not being good at math does not mean one is not as smart as they next guy.
Member Since: Posts: Comments:
1983. Patrap
Rut-roh.

Im getting a hard hat,fast.

Member Since: July 3, 2005 Posts: 426 Comments: 128667
The SPC has issued their first Tornado Watch after the the first tornado was sighted in AL. Then they drop all the Tornado/Severe T-Storm Watches while a Tornado Warning is out for SC and a Severe T-Storm Warning in NY.
Member Since: August 25, 2009 Posts: 20 Comments: 6785
Don't let bad math teachers kill your dreams :(
Member Since: August 12, 2007 Posts: 11 Comments: 2448
1979. Patrap
.."nicely making way"..

from the portlight featured blog entry this evening..


6. SailorsMom 5:13 PM CDT on April 08, 2010

The relief supplies are on their way to Haiti aboard the Schooner Halie & Matthew. PUBLIC UPDATE: The schooner Halie and Matthew departed yesterday at 16h00 for Haiti. After a full day at sea, she was sailing well near Grand Bahama island. They were averaging 6 kts boat speed, and have been tacking into a easterly headwind for the last 24 hours, so their velocity made good is only around 3 kts. The slow progress is likely to continue since the winds will remain east, and then south east as they make their way through the Bahama chain of islands. The crew are all doing well, nobody is seasick, and except for a slight leak around the rudder shaft, all systems are in good working order.




Member Since: July 3, 2005 Posts: 426 Comments: 128667
Quoting tornadodude:


oh ok, cool cool, I had bad teaching throughout my schooling, so my math isnt up to par


Same here. Quality math teachers are difficult to come by, and its such a shame.
Member Since: Posts: Comments:
1977. 47n91w
Quoting StSimonsIslandGAGuy:


Does the grass stay that green all winter? Under the snow?


No, it usually turns a terrible brown. However, all of Wisconsin has had a warm and dry spring, reaching up to 80 in the southern half a couple times, 70s across the rest of the state. I'd venture that areas that have seen the warmest temps in the last week or two have the greenest grass (until it got covered by snow this morning).

Mine (a bit farther north than OSNW3) is mid-way in the transition process but now I need to re-rake all the freaking leaves off the lawn again.
Member Since: Posts: Comments:
Quoting FLWeatherFreak91:
I studied met for my freshmen year... same problem with the math. I'm going to study anthropology and transfer to UWF.


oh ok, cool cool, I had bad teaching throughout my schooling, so my math isnt up to par
Member Since: June 28, 2006 Posts: 25 Comments: 8360
silence please ..Stewie and Brian are potty training...
Member Since: Posts: Comments:
Quoting Patrap:
Someone needs a NOAA Radio,cuz dat Charleston Alert Tone would have sounded in someones ear by now.
Hint,hint.



...and the sad part is....I can't think of a good excuse...or a single reason why you're wrong...
Member Since: Posts: Comments:
Quoting FLWeatherFreak91:
I studied met for my freshmen year... same problem with the math. I'm going to study anthropology and transfer to UWF.


Think you can do underwater archaeology there. Could go hand in hand with anthropology.
Member Since: Posts: Comments:
1972. Patrap
Someone needs a NOAA Radio,cuz dat Charleston Alert Tone would have sounded in someones ear by now.
Hint,hint.

Member Since: July 3, 2005 Posts: 426 Comments: 128667
Quoting presslord:
Aussie....Are you tryin' to steal my stalker?

oh, you can keep him
Member Since: Posts: Comments:
Quoting FloridaTigers:


Just ignore JFV. "It" is back.

Only people i know can call me mate. That was 1 reason why i have ignored him. Pity "it" can't be permanently banned
Member Since: Posts: Comments:
1969. Patrap
Quoting presslord:
I'm torn between watching local weather....and Family Guy....I think if Pat can keep me posted on the storm, Peter Griffin is gonna win...


Peter is wiser than most would think..Huh,huh,huh
Member Since: July 3, 2005 Posts: 426 Comments: 128667
Up to 4 Tornadoes and 70 SPC Damage reports as of 10:30PM CDT today, what a wild day:
Member Since: August 25, 2009 Posts: 20 Comments: 6785
1967. Patrap
negative,,cept maybe the TDRW site is down
Member Since: July 3, 2005 Posts: 426 Comments: 128667
Quoting tornadodude:
yeah I was a meteorology student last semester. switched to public relations, math is a pain!
I studied met for my freshmen year... same problem with the math. I'm going to study anthropology and transfer to UWF.
Member Since: Posts: Comments:
1965. Patrap
That K2 Cell looks Nasty in Jersey
Member Since: July 3, 2005 Posts: 426 Comments: 128667
1964. flsky
Quoting Patrap:



Thanks! Any idea why I couldn't pull it up?
Member Since: Posts: Comments:
Quoting PcolaDan:


not going anywhere NEAR that one



...well.....I can hope...
Member Since: Posts: Comments:
1962. Patrap

505
WUUS51 KOKX 090320
SVROKX
NJC003-031-NYC071-087-090400-
/O.NEW.KOKX.SV.W.0001.100409T0320Z-100409T0400Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE NEW YORK NY
1120 PM EDT THU APR 8 2010

THE NATIONAL WEATHER SERVICE IN UPTON NY HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
PASSAIC COUNTY IN NORTHEAST NEW JERSEY...
ROCKLAND COUNTY IN SOUTHEAST NEW YORK...
SOUTHEASTERN ORANGE COUNTY IN SOUTHEAST NEW YORK...
NORTHWESTERN BERGEN COUNTY IN NORTHEAST NEW JERSEY...

* UNTIL MIDNIGHT EDT...

* AT 1115 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
LINE OF SEVERE THUNDERSTORMS CAPABLE OF PRODUCING DAMAGING WINDS IN
EXCESS OF 60 MPH. THESE STORMS WERE LOCATED ALONG A LINE EXTENDING
FROM 11 MILES WEST OF WEST MILFORD TO 10 MILES SOUTHWEST OF
BLOOMINGDALE...OR ALONG A LINE EXTENDING FROM 8 MILES NORTH OF
HOPATCONG TO DOVER...AND MOVING NORTHEAST AT 55 MPH.

* SEVERE THUNDERSTORMS WILL BE NEAR...
WEST MILFORD...POMPTON LAKES AND BLOOMINGDALE BY 1125 PM...
WARWICK...RAMSEY...RINGWOOD AND GREENWOOD LAKE BY 1135 PM...
MONSEY...SUFFERN AND SLOATSBURG BY 1140 PM...

LAT...LON 4119 7438 4126 7451 4159 7396 4151 7399
4145 7399 4140 7395 4132 7398 4129 7395
4124 7397 4118 7392 4093 7428 4097 7428
4099 7431 4101 7443 4104 7444 4102 7448
4103 7450 4108 7451
TIME...MOT...LOC 0319Z 230DEG 46KT 4110 7455 4098 7445


Member Since: July 3, 2005 Posts: 426 Comments: 128667
Aussie....Are you tryin' to steal my stalker?
Member Since: Posts: Comments:
1960. Patrap


Member Since: July 3, 2005 Posts: 426 Comments: 128667
Quoting KEEPEROFTHEGATE:
now you gone and done it aussie now emails and phone cals will start

He can call me if he wants, it'll cost him an arm, a leg and an ear.
Member Since: Posts: Comments:
Quoting AussieStorm:

I haven't seen you around before yet you comment on xcool's maps.

btw, your not my mate, I don't know you. so don't call me mate. Bucko


Just ignore JFV. "It" is back.
Member Since: Posts: Comments:
I'm torn between watching local weather....and Family Guy....I think if Pat can keep me posted on the storm, Peter Griffin is gonna win...
Member Since: Posts: Comments:
Quoting PcolaDan:


not going anywhere NEAR that one


LOL
Member Since: June 28, 2006 Posts: 25 Comments: 8360
1955. KEEPEROFTHEGATE (Mod)
Quoting AussieStorm:

I haven't seen you around before yet you comment on xcool's maps.

btw, your not my mate, I don't know you. so don't call me mate. Bucko
now you gone and done it aussie now emails and phone cals will start
Member Since: Posts: Comments:

Viewing: 2005 - 1955

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | 32 | 33 | 34 | 35 | 36 | 37 | 38 | 39 | 40 | 41 | 42 | 43 | 44 | 45 | 46Blog Index

Top of Page

About

Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.

Local Weather

Mostly Cloudy
76 °F
Mostly Cloudy