New Category 5 record for the Hurricane Season of 2005

By: Dr. Jeff Masters , 4:21 PM GMT on March 22, 2006

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The astounding Hurricane Season of 2005 has extended its grip on the record for most Category 5 hurricanes in a season. According to the National Hurricane Canter report on Hurricane Emily released earlier this month, Emily is now recognized as a Category 5 hurricane. This brings the record for most Category 5 hurricanes in a season to four (Emily, Katrina, Rita, and Wilma). The old record was two Category 5 storms, set in 1960 and again in 1961. Emily is the earliest-forming Category 5 hurricane on record in the Atlantic basin and the only known hurricane of that strength to occur during the month of July.

According to the report, Emily was a Category 5 hurricane with 160 mph winds and a 929 mb central pressure for about six hours at 00 GMT July 17 2005, while located approximately 115 miles southwest of Jamaica. The storm weakened somewhat before making landfall on the Mexican coast near Cozumel Island as a Category 4 storm with 135 mph winds and a storm surge of up to 15 feet. Emily went on to cross the Gulf of Mexico and slam ashore on the Mexican coast south of Brownsville, Texas, as a Category 3 hurricane. Emily killed one person on its passage over Grenada as a Category 1 hurricane, and five in Jamaica. Amazingly, no one died in Mexico as a result of these two powerful hurricane strikes on the coast--a tribute to the successful evacuation efforts by the Mexicans. In addition, Mexico suffered only four deaths from Hurricane Wilma's four-day pounding. Wilma started out as a Category 4 hurricane when it hit Cozumel Island, and gradually weakened to a Category 2 hurricane as it plowed north over Cancun and eventually into the Gulf of Mexico. Mexico's feat of surviving two Category 4 hurricane strikes and a Category 3 strike to populated areas, with only four deaths, is a civil defense success unparalleled in hurricane history.


Figure 1. Hurricane Emily at its peak strength--a Category 5 storm with 160 mph winds.

One other interesting item to note about Emily: the official NHC track forecast out to four days was better than any of the computer forecast models. Five-day forecasts by a few of the models such as the GFS were better than the official forecast, though. In general, the official NHC forecast was tough to beat over the course of the Hurricane Season of 2005.

Jeff Masters

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175. jeffB
6:28 PM GMT on March 24, 2006
Frankly, the initial paper should never have been published, and if Science didn't have a political agenda behind pushing these types of research, that paper never would have seen the light of day.

Yes, yes, that must be it. Science and Nature routinely subvert the scientific process to further their political agendas. And their impact factors routinely rank in the top ten because scientists as a class are also pushing the same agenda. The cads.
Member Since: July 8, 2005 Posts: 0 Comments: 42
174. jeffB
6:23 PM GMT on March 24, 2006
F5 wrote:

What I find truly interesting, is that the only thing you can criticize is the presentation, not the conclusions presented by the author. That is typical of those who disagree with the position of people who disagree with them. Rather than attack their position, they attack the person.

As opposed to generalizing the behavior of the entire group of people opposing them?

I criticize the presentation because it's so egregious. The facts have been debated, and continue to be debated at great length here and elsewhere. I'm not in the thick of climatological research, so I appreciate well-written, well-documented and well-supported expositions of the issues. I do NOT appreciate rants posing as scientific discussion, using emotionally loaded language in place of (or even in addition to) reasoned discussion. As a matter of personal bias, I'm also deeply suspicious of "Help! Help! I'm being repressed!" claims, particularly in this age of instant dissemination via the Internet.

Incidentally, before you throw around the charge of "attacking the person", please read through my response above and point out all the places where I referred to the author, as opposed to this particular paper. I didn't even attack you -- I addressed the response to you by name, since you posted the link, but my comments were solely restricted to the paper. I'm not the one initiating personal attacks, or even commenting on another poster's tactics, much less generalizing them to an entire imagined class of people.
Member Since: July 8, 2005 Posts: 0 Comments: 42
173. F5
5:35 PM GMT on March 24, 2006
Maybe you should have read these links too...

Link

This is a portion from another link...
The new findings, which are reported today in Science magazine, emerge from gravity measurements made by the two Grace (Gravity Recovery and Climate Experiment) satellites between April 2002 and August 2005.

Variations in the Earth's gravitational field over time can be used to detect alterations in the distribution of its mass. This in turn provides a sensitive way of tracking changes in the mass of the ice sheet.

"Grace has some real advantages over the other methods of looking at ice-sheet mass balance," said Prof David Vaughan of the British Antarctic Survey, Cambridge. "For example, it can 'see' the entire ice sheet."

However, he said that corrections had to be applied to the signal for this method to work and that the accuracy of the final assessment of ice-sheet mass balance depended on how accurate these corrections were.

Considering that the Antarctic region has actually been experiencing a slight cooling trend over the past 25 years (-0.01 °C/decade), it would seem unlikely that "global warming" would be causing any supposed "melting" of the antarctic ice sheet(s). However, even if the amount of ice is changing, you simply cannot translate a 34 month period of data into a long term trend, especially when the subject in question is known for variability in the quantity of ice it contains. Frankly, the initial paper should never have been published, and if Science didn't have a political agenda behind pushing these types of research, that paper never would have seen the light of day.
172. F5
5:19 PM GMT on March 24, 2006
jeffB,

Considering there were a number of links to different reports, measurement data, blogs, etc., I find it interesting that you chose to read one item only and found it "lacking". The first link was a critique of the Antarctica paper, not a research project project. It has a significant presentation of data, referencing many other publications, and is presented to critique the originating paper. What I find truly interesting, is that the only thing you can criticize is the presentation, not the conclusions presented by the author. That is typical of those who disagree with the position of people who disagree with them. Rather than attack their position, they attack the person.

"As I said, an embarrassment. In fact, I'd go so far as to call it "appalling." When I go to scientific conferences, I expect science, not emotion-laden rhetoric."

The question should be, are the critiques of the author valid, is the data in question, can people discern different interpretations, etc. Yourself and snowboy have failed to answer that question completely, along with the general question posed in the other link...Namely, how can a scientific paper purport a long term trend based on 34 months worth of data, especially when contradictory data exists? If anything is an embarassment, it would be that.
171. jeffB
4:00 PM GMT on March 24, 2006
F5, I actually read the entire paper at that first link you posted. It is an impressive piece of polemic, but it's an embarrassment as a scientific paper.

It's not clear to me whether this was a refereed paper, an invited talk, or something else. I don't see a lot of references to the conference, except from a handful of self-described conservative blogs. (Incidentally, while the PDF claims that it "WILL APPEAR IN THE PROCEEDINGS OF THE 2005 ERICE MEETING OF THE WORLD FEDERATION OF SCIENTISTS ON GLOBAL EMERGENCIES", the conference was actually the 34th "INTERNATIONAL SEMINAR ON NUCLEAR WAR AND PLANETARY EMERGENCIES", in case anyone's trying to track down the original source.)

The paper makes some claims about model reliability, overlooked natural processes, and so forth, but focuses mostly on other areas. (In fact, in the Acknowledgements section, he specifically states that "preparation of the scientific portions of this paper were supported by the US Department of Energy".)

Much of the paper focuses on "public opinion". If you're making points about public opinion, you're doing sociology, not climatology, and you should use its tools -- opinion polls, measurements of space and time devoted to various points of view in the media, and so forth. This paper has nothing like that, so it's not sociology.

Other parts of the paper focus on political policy. Again, this is sociology, not climatology. It certainly appears to be on-topic for a conference of this nature, but here again, the paper presents no data, only anecdote and polemic.

So, if the paper is so short on actual data, what DO all those words give us? Well, there are lots of juicy ones:

the mantra for alarmism

reprehensible attempts to generate alarm

an almost self-parodying habit of those proclaiming alarm

a touching faith in models

‘fools walking in where angels fear to tread’

leaning over backwards to encourage the alarmists

The sad tale of the triangle of alarmism and the iron rice bowl of science

Only the most cynical propagandist could have anticipated that sentient human beings could be driven into panic


As I said, an embarrassment. In fact, I'd go so far as to call it "appalling." When I go to scientific conferences, I expect science, not emotion-laden rhetoric.

Amid all the florid prose, though, there are nuggets of wisdom. I particularly liked the opening of Part 9, Science and Policy:

The mixture of science and policy often leads to absurdity[...]

...and we're certainly seeing that in today's climate policies. But the very best part comes in the conclusion:

At the heart of this issue there is one last matter: namely, the misuse of language. George Orwell wrote that language “becomes ugly and inaccurate because our thoughts are foolish, but the slovenliness of our language makes it easier for us to have foolish thoughts.”

Truer words were never spoken. Or, for that matter, exemplified.
Member Since: July 8, 2005 Posts: 0 Comments: 42
170. F5
3:12 PM GMT on March 24, 2006
Snowboy,

Despite the writing style of the person who wrote those comments, did you bother to read any of the links to the scientific data or publications? Of course you didn't. You wouldn't want to expose yourself to any research that doesn't mesh with your point of view.

I notice you didn't deny any of the Hansen story either. How could you; Hansen himself didn't deny it.

169. Undertaker
2:30 PM GMT on March 24, 2006
Hey peeps what's up? It's nice to see that you all enjoyed the little information I posted about Jamaica but we may be in for the worst season ever. Last night on the news we saw were the police and soldiers were burning 10 acres of Marijuana in a field that they found and man this is not good news when the Hurricane season is only 2 months away. We may have to protest and plant some more hoping that it grows in time for june 1st. We would like to apologize to the people from Cazamul Mexico we have to take resposibilty for what Wilma did to you. If you notice this system formed over or near jamaica. Man we fed this system so much weed that it decided to take a spring break.This system consumed so much marijuana that I beleive it is the strongest Hurricane in history. We may need to look at a new way of distributing weed to hurricanes probably we could meet the storms out at see and give them what the want so they all turn north out to see.
Member Since: August 4, 2005 Posts: 0 Comments: 50
167. KatrinaRitaWilmaZeta
1:51 PM GMT on March 24, 2006
***Happy 21st Birthday*** to me so drop me a post ***Happy 21st Birthday*** to me
166. snowboy
6:57 AM GMT on March 24, 2006
F5, here are a few of the breathy bits of descriptive rhetoric from YOUR 12:14 am GST post:


Ooh! Bad headlines! Is Antarctica 'melting'? The definitive answer is 'No, not currently'.

'Aha!' cry the hand-wringers, '"Unproven" satellite data must be wrong!'.

What an absurd beat up from almost non-extant data! Maybe NASA is getting in very early for April 1? And what an appalling media response with no one yet observed treating these claims with any degree of scepticism. Sheesh!

Pretty sad state of general media, so far we've only noted London Telegraph's Roger Highfield adding any caveat to this story while most of the majors have uncritically regurgitated this pap.

...NASA's motivation for swamping the PR networks with their breathless blurt ... we fear the instructions for the Shuttle's replacement may be something akin to "Ignite blue touch paper and stand clear..."


If you can't see the difference between this and solid science then I can't help you.
Member Since: September 21, 2005 Posts: 10 Comments: 2555
165. F5
6:38 AM GMT on March 24, 2006
Snowboy,

It's only right-wing propoganda to someone who refuses to acknowledge that there are serious questions as to the accuracy of anything that supports your belief. Do you deny the information on Dr. Hansen? Are you saying it's all made up? Are you denying that the study of Antartica's ice sheet only covered 3 years? Are you denying that other data shows the Antartica ice sheet to be expanding?

Richard S. Lindzen, Professor of Atmospheric Sciences at the Massachusetts Institute of Technology (MIT), brilliantly washes global warming's dirty linen and hangs it out to dry: 'Understanding common climate claims' (Draft of a paper to be published [.pdf]). Here is the Abstract:

"The issue of man-induced climate change involves not the likelihood of dangerous consequences, but rather their remote possibility. The main areas of widespread agreement (namely that global mean temperature has risen rather irregularly about 0.6C over the past century, that atmospheric levels of carbon dioxide have increased about 30% over the past century, and that carbon dioxide by virtue of its infrared absorption bands should contribute to warming) do not imply dangerous warming. Indeed, we know that doubling carbon dioxide should lead to a heating of about 3.7 watts per square meter, and that man-made greenhouse heating is already about 2.7 watts per square meter. Thus, we have seen less warming than would be predicted by any model showing more than about 0.8 degrees C warming for a doubling of carbon dioxide. This is consistent with independent identifications of negative feedbacks.

Alarming scenarios, on the other hand, are typically produced by models predicting 4 degrees C. After the fact, such models can only be made to simulate the observed warming by including numerous unknown factors which are chosen to cancel most of the warming to the present, while assuming that such cancellation will soon disappear. Alarm is further promoted by such things as claiming that a warmer world will be stormier even though basic theory, observations, and even model outputs point to the opposite.

With respect to Kyoto, it is generally agreed that Kyoto will do virtually nothing about climate no matter what is assumed. Given that projected increases in carbon dioxide will only add incrementally to the greenhouse warming already present, it seems foolish to speak of avoiding dangerous thresholds. If one is concerned, the approach almost certainly is to maximize adaptability."

Here's the link to the paper...
Link

Or how about this...Scroll down to the March 3rd entry...Link

Read the links in the commentary. Oh wait, let me guess, it's all right wing propoganda, so no need right? Wouldn't want to possibly read anything that doesn't agree with your pre-conceived notion of what is.

I see you haven't been able to rid yourself of those pesky ad-hominem attacks either. Note that I didn't attack the writers of the article posted by dallastornado1957. I try to show respect for both sides, even if I disagree with it. I didn't call it left-wing propoganda, liberal hog-wash, or anything else. Simply posted some rebuttal material. Maybe you should think about expanding your horizons and actually read what both sides say, rather than just those things that agree with you. You might actually learn something in the process. You might still come to the same conclusion you already have, but maybe you would at a minimum show some respect for those who have a different perspective.
164. snowboy
5:51 AM GMT on March 24, 2006
trwling = trawling

mclori there are no "dumb" questions.. the Great Lakes are upstream of the oceans and thus unaffected by changes in sea level.

What will happen to Great Lakes water levels as a result of the anticipated global warming is a matter of great concern, but the overall consensus appears to be that a combination of greater evaporation plus diminished precipitation will gradually lower lake levels. No sure sign that this is happening yet..
Member Since: September 21, 2005 Posts: 10 Comments: 2555
163. snowboy
5:44 AM GMT on March 24, 2006
F5, you've got to stop trwling those right-wing sites when looking to respond to articles from peer-reviewed scientific journals (like the one posted by dallastornado1957.

Sure you can gets acres of right-wing verbiage purporting to "refute" the science, but it's all spin. Get us the peer-reviewed rebuttals which refute the Science article and we'll start paying attention.
Member Since: September 21, 2005 Posts: 10 Comments: 2555
162. mclori
5:30 AM GMT on March 24, 2006
I'm pretty naive about many things, so please bear with me if my question seems "dumb." What will happen with the Great Lakes as the oceans rise due to temperature rising and ice melting?
Member Since: August 28, 2005 Posts: 6 Comments: 8
161. F5
5:18 AM GMT on March 24, 2006
Also, for those of you to whom Dr. Hansen is a hero, read this...

Link
160. F5
5:16 AM GMT on March 24, 2006
Sorry, forgot the link to the above...

Link
159. F5
5:14 AM GMT on March 24, 2006
Oops! 'Trends' from <3.5 years data? "Antarctica's Annual Melt Equals Water in Lake Tahoe, Study Says" - "Antarctica is melting at an annual rate equal to dumping Lake Tahoe into the ocean, causing global seawater to rise as much as 0.6 millimeters (0.02 inches) a year, according to a study published by Science. Researchers used two NASA satellites to measure the loss of the ice sheet on the Earth's fifth-largest continent between April 2002 and August 2005. The findings contradict an Intergovernmental Panel on Climate Change assessment in 2001, which predicted the ice sheet would gain mass in the 21st century. ``We can now see Antarctica melting,'' said Isabella Velicogna, a member of the University of Colorado at Boulder's Cooperative Institute for Research Environmental Sciences. ``We have a number for the ice sheet. It's a big step toward understanding how the sea level is going to change.'' (Bloomberg) | Measurements of Time-Variable Gravity Show Mass Loss in Antarctica | PDF (Science) | See Google News listing for lots of bad coverage of this.

Ooh! Bad headlines! Is Antarctica 'melting'? The definitive answer is 'No, not currently'.

How do we know this? Since 1979 we have had satellite coverage of the frozen continent and the UAH MSU data for the Southern Polar Region, displayed graphically here, shows a slight cooling trend of -0.01 °C/decade.

'Aha!' cry the hand-wringers, '"Unproven" satellite data must be wrong!'. Fair enough, ignoring the fact these headlines are generated from, ahem, just 3 years, 5 months satellite data, let's compare the MSU data with Goddard Institute of Space Studies (a.k.a. the "House of Hansen") data, displayed here. Their trend is different from that of the UAH MSU, indicating greater Antarctic cooling at -0.04 °C/decade for the period 1979-2005.

GHCN-ERSST plotted here for the region 66.33S - 90.00S over the same period gives a trend of -0.02 °C/decade.

The cooperative effort by the UK Met. Office's Hadley Centre and University of East Anglia's Climatic Research Unit dataset known as HadCRUT2v also provides regional splits and their data, shown here, for the Antarctic not including the peninsula protruding north of the Antarctic Circle, shows no trend (0.0 °C/decade) for the period 1979-2004 while the Antarctic Peninsula, here, shows an anomalous trend of +0.5 °C/decade. Their combined 65S - 90S (including part of the Southern Ocean), here, gives a trend of +0.1 °C/decade.

The Antarctic is not exactly over-serviced with historical temperature data and some extraordinary gyrations appear in what record we do have - probably as a result of measurement changes but possibly not. During the period of global cooling worry the Antarctic appears to have been warming although we cannot determine whether the changes around the 1950s are the result of some sort of phase shift or alterations in temperature recording and calculation. What we don't have is any indication of a warming trend within the Antarctic Circle during the period of allegedly alarming anthropogenic global warming (our so-called 'hottest decades' of the 'hottest century' for a millennium). And if the sub-zero south is not warming then it is not melting, is it?

Continental ice egress is not a smooth and steady procedure but seems to happen in fits and starts. Some of the reason for this is ice sheets adding significant resistance as they slowly grow out to sea until eventually stalling ice flow. Eventually tide and currents break off these extruded sheets, releasing back pressure and allowing temporary 'sprints' of ice streams to sea, slowly rebuilding the blocking sheets until the cycle repeats. Over the last decade we have seen ice shelves in several regions around Antarctica breaking back to levels last seen in the 1950s so if there is a net transient loss in progress no one would (or should) really be surprised.

What is perhaps more surprising is the number of distribution points utilised by NASA putting out their press release regarding just 3 years and 5 months data (April 2002 to August 2005), which is one reason the 'trend' confidence is ±50% - another is that 'corrections' of unknown efficacy have had to be applied to the signal in an attempt to use this technique to derive ice shield mass balance. What do you suppose would be the response if we used the same period of UAH MSU data to claim a global temperature 'trend'? For those who might be interested, under comparable trend guidelines as used by NASA above, the world is heading into a chill, with global cooling 'trend' of -0.013 °C/decade (can I get a place in Igloo Building 101?).

What an absurd beat up from almost non-extant data! Maybe NASA is getting in very early for April 1? And what an appalling media response with no one yet observed treating these claims with any degree of scepticism. Sheesh!

Update: 22:50 GMT - Pretty sad state of general media, so far we've only noted London Telegraph's Roger Highfield adding any caveat to this story while most of the majors have uncritically regurgitated this pap. On the plus side of the ledger TCS Daily is hosting Pat Michael's response: Antarctic Ice: The Cold Truth while The Commons Blog has Long Term Policy, Short Term Data — A Poor Fit.

If NASA proliferated somewhat suspect virtual snapshot data* as a test of the media's scientific literacy - and we sincerely hope that was NASA's motivation for swamping the PR networks with their breathless blurt - then the media failed the test and failed it big. If NASA has seriously released and promoted this as a conclusion securely based on thorough observation and robust science then we fear the instructions for the Shuttle's replacement may be something akin to "Ignite blue touch paper and stand clear..." Make no mistake, the underlying science is dazzling and may prove extraordinarily useful in time but the difference between a snapshot and a trend, at least in terms of planetary climate, is at least thirty years, something of which NASA is well aware.

* so labelled because it contradicts other longer-term satellite analyses with a 'series' so short it is analogous to having a child tell you whether a flashing light is working: "Yes it is, no it isn't, yes it is...".

Apparent contradictions explained:) "Antarctic Ice Increasing AND Decreasing" - "Seemingly contradictory research results, such as recent reports of both decreasing and increasing Antarctic ice, can be explained with a new metaphysical theory." (ecoEnquirer)

Thanks to everyone who e-mailed to point out that just 34 months data is involved and thus less than 3 years, which is true, however the span of the data is April 2002 to August 2005 and we assume the 'trend' refers to the maximum span.
158. louastu
5:12 AM GMT on March 24, 2006
I am not saying that if the oceans rise that it would not be a disaster. I am simply saying that it would not kill millions of people.
157. louastu
5:05 AM GMT on March 24, 2006
cyclonebuster,

If an ice shelf the size of Manhattan broke off it would be a lot smaller than a piece that broke off in 2000. In 2000 there was an iceberg the size of Long Island. Manhattan is only 23.7 sq. miles, while Long Island is 1377 sq. miles.
155. louastu
4:40 AM GMT on March 24, 2006
I find it hard to believe that the ice caps would melt so quickly that the ocean would rise faster than people could get out of the way. In fact I suspect that they would rise at a rate that even a snail would have a chance.
154. KatrinaRitaWilmaZeta
4:38 AM GMT on March 24, 2006
tell me this can your tunnels stop a cat 5 hurricane hiting the uea be for land fall
152. KatrinaRitaWilmaZeta
4:33 AM GMT on March 24, 2006
i do not think i want to her about tunnels all of hurricane year 2006 do any of you it will drive us all lol
150. dallastornado1957
4:29 AM GMT on March 24, 2006
Sorry I can't copy the graphic- which eliminates about a third of Florida and everything south of and including Lake Ponchartrain in Louisiana.

Science 24 March 2006:
Vol. 311. no. 5768, pp. 1698 - 1701
DOI: 10.1126/science.311.5768.1698

News Focus
CLIMATE CHANGE:
A Worrying Trend of Less Ice, Higher Seas
Richard A. Kerr

Startling amounts of ice slipping into the sea have taken glaciologists by surprise; now they fear that this century's greenhouse emissions could be committing the world to a catastrophic sea-level rise

Going? Greenland glaciers like those dumping into Sondre Sermilik Fjord have sped up and retreated.

HAVE AN URGE LATELY TO RUN FOR higher ground? That would be understandable, given all the talk about the world's ice melting into the sea. Kilimanjaro's ice cloak is soon to disappear, the summertime Arctic Ocean could be ice-free by century's end, 11,000-year-old ice shelves around Antarctica are breaking up over the course of weeks, and glaciers there and in Greenland have begun galloping into the sea. All true. And the speeding glaciers, at least, are surely driving up sea level and pushing shorelines inland.
Scientists may not be heading for the hills just yet, but they're increasingly worried. Not about their beach houses being inundated anytime soon; they're worried about what they've missed. Some of the glaciers draining the great ice sheets of Antarctica and Greenland have sped up dramatically, driving up sea level and catching scientists unawares. They don't fully understand what is happening. And if they don't understand what a little warming is doing to the ice sheets today, they reason, what can they say about ice's fate and rising seas in the greenhouse world of the next century or two?

That uncertainty is unsettling. Climatologists know that, as the world warmed in the past, "by some process, ice sheets got smaller," says glaciologist Robert Bindschadler of NASA's Goddard Space Flight Center (GSFC) in Greenbelt, Maryland. But "we didn't know the process; I think we're seeing it now. And it's not gradual." Adds geoscientist Michael Oppenheimer of Princeton University, "The time scale for future loss of most of an ice sheet may not be millennia," as glacier models have suggested, "but centuries."

The apparent sensitivity of ice sheets to a warmer world could prove disastrous. The greenhouse gases that people are spewing into the atmosphere this century might guarantee enough warming to destroy the West Antarctic and Greenland ice sheets, says Oppenheimer, possibly as quickly as within several centuries. That would drive up sea level 5 to 10 meters at rates not seen since the end of the last ice age. New Orleans would flood, for good, as would most of South Florida and much of the Netherlands. Rising seas would push half a billion people inland. "This is not an experiment you get to run twice," says Oppenheimer. "I find this all very disturbing."

A rush to the sea

Much of the world's ice may be shrinking under the growing warmth of the past several decades, but some ice losses will have more dramatic effects on sea level than others. Glaciologists worried about rising sea level are keying on the glaciers draining the world's two dominant ice reservoirs, Greenland and Antarctica. Summertime Arctic Ocean ice may be on its way out, but its melting does nothing to increase the volume of ocean water; that ice is already floating in the ocean. The same goes for floating ice shelves around Antarctic. The meltwater from receding mountain glaciers and ice caps is certainly raising sea level, but not much.

The truly disturbing ice news of late is word that some of the ice oozing from the 3-kilometer-thick pile on Greenland has doubled its speed in just the past few years. In the 17 February issue of Science, for example, radar scientists Eric Rignot of the Jet Propulsion Laboratory in Pasadena, California, and Pannir Kanagaratnam of the University of Kansas, Lawrence, analyzed observations made between 1996 and 2005 by four satellite-borne radars. These synthetic aperture radars measure the distance to the surface during successive passes over a glacier. The changing distance can then be extracted by letting successive observations form interference patterns. The changing distance, in turn, translates to a velocity of the ice toward the sea.

In central east Greenland, Kangerdlugssuaq Glacier more than doubled its speed from 2000 to 2005, Rignot and Kanagaratnam found, from 6 kilometers per year to 13 kilometers per year. That made it the fastest in Greenland. To the south, Helheim Glacier accelerated 60%. And on the west of Greenland, Jakobshavn Isbrae almost doubled its speed between 1996 and 2005. The accelerations are "actually quite surprising," says glaciologist Julian Dowdeswell of the University of Cambridge in the United Kingdom. Even at its slower speed, Jakobshavn had ranked as one of the fastest-flowing glaciers in the world, perhaps the fastest; now it's just one of the pack.

As glaciers draining the Greenland Ice Sheet are picking up speed, researchers are realizing that nothing has made up for the increased loss of ice. Greenland's pile of ice is getting smaller. How much smaller is still being debated, if only because of the vast scope of an ice sheet. What goes out through glaciers is just one part of the equation: Ice sheets also lose mass by melting and gain it from snowfall. To gauge those gains and losses, Rignot and Kanagaratnam used previously published estimates of how the warming climate over Greenland has increased meltwater losses and slightly increased snowfall, making for a growing net loss in addition to the glacier flow. All told, the scientists find that the loss of mass from Greenland doubled from 1996 to 2005, reaching 224 ± 41 cubic kilometers per year. Los Angeles uses 1 cubic kilometer of water per year.

In another approach to estimating mass balance, researchers sketch the changing shape and therefore volume of the ice sheet. In a paper just out in the Journal of Glaciology, glaciologist Jay Zwally of GSFC and colleagues use satellite radars to measure the height of the Greenland Ice Sheet's broad plateau and airborne laser altimeters to monitor the height of glaciers draining to the coast, which are too small for satellite radars to see reliably. "We have strong evidence the ice sheet was near balance [during] the last decade of the 20th century," says Zwally. "Our measures show a slight positive gain of 11 [cubic kilometers] per year" between 1992 and 2002.

Global warming contrarians have already taken up Zwally's result as evidence that nothing much is happening with the ice sheet, so there's nothing to worry about. Zwally disagrees. "There's no question there's been an acceleration of some of Greenland's glaciers over the last 5 years," after his surveys were completed, he says. "I would say that right now the current loss is 30 to 40 [cubic kilometers] per year," he says, based on his gut feeling about the most recent radar and laser observations.

That's getting close to the mass loss reported last fall using a third approach: repeatedly weighing the ice sheet. Geophysicists Isabella Velicogna and John Wahr of the University of Colorado, Boulder, reported in Geophysical Research Letters how the two satellites of the Gravity Recovery and Climate Experiment (GRACE), flying in tandem, gauge the mass beneath them. They precisely measure the changing distance between them caused by the gravitational pull of the passing ice. Between 2002 and 2004, GRACE found a loss of about 82 cubic kilometers of ice per year.

Going under? Global warming might trigger a 6-meter rise in sea level that would inundate coasts worldwide. Southern Louisiana and South Florida would be hard hit.

All things considered, it seems clear that "Greenland has been shifting to a negative mass balance the last few years," says glaciologist Richard Alley of Pennsylvania State University in State College. The same can be said for the West Antarctic Ice Sheet. All recent surveys have the far more massive East Antarctic Ice Sheet slowly gaining mass from increased snowfall. But that gain falls far short of compensating for the loss from West Antarctica. There, Zwally's analysis has the ice shrinking by about 47 cubic kilometers per year. And Velicogna and Wahr, writing in this week's issue of Science (p. 1754), report a GRACE-estimated loss of about 148 cubic kilometers per year. In West Antarctica, as in Greenland, the culprit is the acceleration of outlet glaciers in recent years (Science, 24 September 2004, p. 1897).
Why the rush?

The recent proliferation of galloping glaciers caught researchers unawares. "None of the models [of glacier flow] predict there should be such rapid change," says glaciologist Ian Joughin of the University of Washington, Seattle (see Perspective on p. 1719). "If you look at a textbook, you'll see an ice sheet response time of 1000 years or more." That's because models "treat ice sheets as a big lump of ice," he says. They melt, or they don't melt.

In the case of West Antarctica, there is tentative agreement about what is triggering the acceleration of the glaciers. Around the Palmer Peninsula that juts northward from West Antarctica, the world's strongest regional warming of the past 50 years first puddled the surface of ice shelves with meltwater. The meltwater then drove into the ice along growing cracks, breaking up shelves over a few weeks. Without the shelves to hold them back, apparently, the glaciers feeding them sped up (Science, 30 August 2002, p. 1494). To the south, where it's still far too cold for surface melting, a third-of-a-degree warming of the ocean seems to have eaten away at the shelves jutting into the Amundsen Sea. That in turn sped up Pine Island Glacier and its neighbors.


Off to sea. The acceleration of glaciers draining both the Greenland and Antarctic ice sheets has meant more icebergs and thus more sea-level rise around the world.
CREDIT: FRANK LUKASSECK/ZEFA/CORBIS


Around Greenland, however, both surface melting and shelf-bottom melting seem to be happening to some extent. Surface melting around the ice sheet's periphery has increased in recent years. Some of the meltwater plunges into open crevasses, where Zwally has shown that it can lubricate the bottom of the ice and accelerate ice flow. But, as Bindschadler argues on page 1720 of this issue of Science, the accelerating Greenland glaciers all flow through deep troughs that expose the ice to any warming ocean water, and all lost their buttressing ice shelves before or during acceleration. So both mechanisms are plausible drivers of glacier acceleration, but glaciologists cannot agree on their relative importance.
Whither the world's ice

If the recent behavior of ice sheets is not fully understood, their future is largely a blank. "We don't actually understand what's driving these higher velocities," says Dowdeswell, so "it's difficult to say whether that's going to continue," or spread.

At the moment, ice loss from Greenland and West Antarctica combined is contributing less than half of the ongoing 2-millimetersper- year rise in sea level; the rest comes from melting mountain glaciers and the simple thermal expansion of seawater. If the recent surge of ice to the sea continues, sea level might reach something like half a meter higher by 2100. That would be substantial but not catastrophic. To produce really scary rises really fast (say, a meter or more per century), the air and water will have to continue warming in the right--or wrong--places. The temperature rise will have to spread northward around Greenland and in the south around West Antarctica, reaching the big ice shelves where most of that ice sheet drains. And glacier accelerations triggered near the sea must propagate far inland to draw on the bulk of an ice sheet.

Faced with uncertainty about the present, paleoclimatologists look to the past. About 130,000 years ago, between the last two ice ages, the poles may have warmed as much as they will with only a couple of degrees of global warming. But sea level was considerably higher then, something like 3 to 4 meters higher. In two articles in this issue of Science, paleoclimatologist Jonathan Overpeck of the University of Arizona, Tucson (p. 1747), paleoclimate modeler Bette Otto-Bliesner of the National Center for Atmospheric Research in Boulder (p. 1751), and their colleagues consider whether the greenhouse world of a century hence might be as warm-- and thus as destructive of ice--as during the previous interglacial.

First they simulated the climate of 130,000 years ago. Back then, Earth was tilted slightly more on its axis, so more solar radiation hit the high northern latitudes, driving warming there. Because the model included that added radiation, it had Greenland warming by about 3°C in the interglacial period. When that warming was put into a model of the ice sheet, the ice melted away slowly (because the model lacked any acceleration mechanisms) until about half remained. That produced enough meltwater to raise sea level 2 to 3 meters. Overpeck and colleagues suggest that another couple of meters of sea level rise could have come from West Antarctica; it was not as warm there, but much of the ice sheet lies below sea level, making it inherently unstable.
When the climate model simulates the next 140 years of rising greenhouse gases, Greenland warms as much by 2100 as it did in the previous interglacial and would thus--eventually--melt as much. "Ice sheets have contributed meters above modern sea level in response to modest warming," Overpeck and his colleagues conclude, and "a threshold triggering many meters of sea-level rise could be crossed well before the end of this century."

The paleoclimate argument for large, imminent ice losses "is fascinating and scary at the same time," says Oppenheimer. "Paleoclimate always has a large amount of uncertainty, [but] we should take this as a serious warning sign. You could lock in a dangerous warming during this century."

An icy conundrum

The ice sheet problem today very much resembles the ozone problem of the early 1980s, before researchers recognized the Antarctic ozone hole, Oppenheimer and Alley have written. The stakes are high in both cases, and the uncertainties are large. Chemists had shown that chlorine gas would, in theory, destroy ozone, but no ozone destruction had yet been seen in the atmosphere. While the magnitude of the problem remained uncertain, only a few countries restricted the use of chlorofluorocarbons, mainly by banning their use in aerosol sprays.

But then the ozone hole showed up, and scientists soon realized a second, far more powerful loss mechanism was operating in the stratosphere; the solid surfaces of ice cloud particles were accelerating the destruction of ozone by chlorine. Far more drastic measures than banning aerosols would be required to handle the problem.

Now glaciologists have a second mechanism for the loss of ice: accelerated flow of the ice itself, not just its meltwater, to the sea. "In the end, ice dynamics is going to win out" over simple, slower melting, says Bindschadler. Is glacier acceleration the ozone hole of sea level rise? No one knows. No one knows whether the exceptionally strong warmings around the ice will continue apace, whether the ice accelerations of recent years will slow as the ice sheets adjust to the new warmth, or whether more glaciers will fall prey to the warmth. No one knows, yet.



149. KatrinaRitaWilmaZeta
4:28 AM GMT on March 24, 2006
hey DR M can you make the photo smaller
146. louastu
4:26 AM GMT on March 24, 2006
I don't know exactly what you mean as far as it making the blog "funky". As far as making it run slower, I have not noticed it to be all that slow. For me this page loads in 5 seconds or less every single time.
145. theboldman
4:25 AM GMT on March 24, 2006
a agree micheal
Member Since: September 8, 2005 Posts: 25 Comments: 2
142. theboldman
4:23 AM GMT on March 24, 2006
michaelSTL come on man

Spread Happiness
Member Since: September 8, 2005 Posts: 25 Comments: 2
141. KatrinaRitaWilmaZeta
4:22 AM GMT on March 24, 2006
too big
140. theboldman
4:21 AM GMT on March 24, 2006
ohh it makes the blog all funky plus run slower
Member Since: September 8, 2005 Posts: 25 Comments: 2
139. KatrinaRitaWilmaZeta
4:21 AM GMT on March 24, 2006
MichaelSTL that a good ?


we would not be seeing it or hering it all of hurricane year 2006 i do not think any one can take it
138. louastu
4:20 AM GMT on March 24, 2006
What is wrong with the size he has up?
137. theboldman
4:20 AM GMT on March 24, 2006
ahhh ok buster keep us informed with the latest
Member Since: September 8, 2005 Posts: 25 Comments: 2
136. theboldman
4:19 AM GMT on March 24, 2006
hey jeffmasters you really need to learn how to resize pics

Member Since: September 8, 2005 Posts: 25 Comments: 2
133. theboldman
4:16 AM GMT on March 24, 2006
do do do doooooooo who ya gona call when a hurricane threatens to hit land cyclonebuster dooo dooo

gost busters theme
Member Since: September 8, 2005 Posts: 25 Comments: 2
131. theboldman
4:13 AM GMT on March 24, 2006
whats up buster hows the tunnel thing goin
Member Since: September 8, 2005 Posts: 25 Comments: 2
130. theboldman
4:13 AM GMT on March 24, 2006
come on guys Be Cool
Member Since: September 8, 2005 Posts: 25 Comments: 2
128. theboldman
4:12 AM GMT on March 24, 2006
ouch
Member Since: September 8, 2005 Posts: 25 Comments: 2
125. ForecasterColby
3:55 AM GMT on March 24, 2006
Floyd is weakening now, shear getting to it. SSD says T5.5.

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

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