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Global Warming Expected to Intensify Hurricanes
DoraLives writes "Think this hurricane season was bad? Well according to the New York Times, a study was published online on Tuesday by The Journal of Climate indicating that warming ocean temperatures are going to make for stronger, wetter hurricanes in the coming years and decades. An abstract of the article concludes cheerfully enough that 'greenhouse gas-induced warming may lead to a gradually increasing risk in the occurrence of highly destructive category-5 storms.' Oh joy."
If you think Florida had it bad, they don't even know how many thousands of people died in Haiti yet, they'll have to dig through the mud to find the bodies. Once they get food that is...
The estimates are one or two thousand dead these days.
You can't take the sky from me...
the hurricanes have been nothing more than intense storms when they make it up to my area (Philadelphia), but they have made a mess. just this last week all over PA, DE and NJ had lots of mess i watched on the local news. there was a few feet of mud from runoff on I-76 just outside the city. they had to get people off a bus using an xtension ladder from the other side of the road (the jersey wall acted like a dam). in all 30 cars and one bus were destroyed. countless houses and stores flodded out. sinkholes all over the place opening up. a lady was killed in the city because the water coming down the sidewalk was so strong it knocked her over and washed her down the street, she got stuck under a car and by the time people pulled her up she had drowned!
But Bush said that greenhouse effect was nonsense!
Even the Bush administration has issued reports saying that global temperatures should rise about 4 degrees over the next century (independent studies say it's more like 10). Global warming is technically a theory, but it's one of the best supported and widely believed in the scientific community. Whether or not humans have played a part in it is up for debate, though. Quick side note: since the last ice age, 1 degree/100 year increase is generally regarded as a fast temperature increase.
Back on topic, any rapid change in climate is going to have some major natural disasters, be it hurricanes or undue rain or even prolonged drought, depending on the area. It's not going to be like that movie where everything happens at once and tidal waves are suddenly racing through manhattan, but florida isn't the only place in for a rough time.
If you get nervous, just remember that there are a few billion other people who don't really give a damn.
Do you know how many senators voted not to ratify the treaty?
98 out of 100. Two senators did not vote.
So even John Kerry voted not to ratify Kyoto. Hell, even fathead Ted Kennedy did. Because it's not about "the environment", it's about shackling the economies of the west. And if you look deeper, you will see the huge trade concessions made to Russia (by EU member states) in order for them to sign.
Apparently, 98 senators who are normally split along party lines figured that one out. There's 1+1=2 for you.
Despite popular confusion, global warming and ozone depletion are two entirely independent phenomena with little or no relation to each other, except that both are probably caused by pollution of differing kinds.
Check out Mother of Storms by John Barnes. EXACTLY this theory was the premise of the book... though taken to it's extreme, of course. :-)
Just for the record, hurricane season lasts until the end of November.
This (more hurricanes) comes as a surprise to anyone? The atmosphere is a heat engine. You put more heat energy in, you get more wind energy out. It's as simple as that. Of course you're going to get more high wind events. In the Carribean, you call those Hurricanes.
What's bemusing to a European eye is that it seems to be the places which are most likely to be devastated by global warming that are most likely to vote for Bush.
I'm old enough to remember when discussions on Slashdot were well informed.
With the way people are blaming everything else in the world on Bush.. I'm surprised.
Bush is getting part of the blame for it, and rightfully so. President Bush and his advisers maintain that reducing emissions through costly near-term measures is unjustified. The White House argues that forecasting climate change is too imprecise to agree to long-term, international, mandatory cuts in greenhouse gas emissions.
In April of 2001, ten of the world's most prominent citizens wrote a letter (published in Time magazine) urging President George W. Bush to reduce the amount of greenhouse gas produced by the United States. Signatories included Stephen Hawking, Jimmy Carter, Mikhail Gorbachev, Senator John Glenn, Walter Cronkite, George Soros, and Jane Goodall. The letter was initiated by Charles Alexander, environment editor of "Time," while he was collaborating on the magazine's project to explore the scientific evidence for the existence and extent of global warming and the political furor over Bush's withdrawal of U.S. support for the Kyoto climate protocol after nine years of international negotiations.
Actor Harrison Ford, who is a board member of Conservation International, signed as did J. Craig Venter who decoded the human genome. Venerable zoologist, ecologist and Pulitzer Prize winning author Edward O. Wilson added the weight of his signature.
Bush apparently round-filed the letter.
Gee, doesn't that sound like he should be shouldering some of the blame?
Not quite true. Ozone is actually a very effective greenhouse gas, more effective than CO2. But stratospheric ozone is needed to protect us from dangerous radiation from the sun.
Pull your head out of your ass. Kyoto was voted down by congress before Bush was even in office.
"Two legs good! Four legs bad!"
Eight years of Clinton... 40+ years of Democrat controlled Congress... Clinton shoots down the Kyoto Accords... and you're blaming Bush? Do ya really think it's a Halliburton-Bush-Bildeberger-Alien Abduction-Jews are Blood Suckers conspiracy? It's shocking how these self-professed intellectuals can latch onto such bizarre, poorly constructed delusions.
Please, take the tin foil hats off. Quit blindly trusting political parties and their media arms (NY Times is one of the least credible news sources now days and every "news" story should be treated as more anti-objective thinking hatred.
Consider this article that explains that the credibile sources understand there is not a cororlation between alleged warming and hurricanes:
FORT LAUDERDALE, Fla. -- As hurricane after hurricane strikes the southeastern United States, many people wonder whether the rash of storms is the result of global warming.
The answer from scientists: Probably not, and certainly not with this year's weather. In fact, the overall global temperatures
Although many experts think global warming could increase the number or the intensity of hurricanes 50 years from now, they say this year's storms were caused by natural changes in the ocean and atmosphere. These include a multi-decade cycle of warm water moving through the Atlantic Ocean, and the unusual mildness of the hurricane-suppressing patch of warm water in the Pacific called El Nino.
"This isn't a global-warming sort of thing," said Hugh Willoughby, senior scientist at the International Hurricane Research Center of Florida International University. "It's a natural cycle."
Curiously, the data shows we're in a cooling pattern (many of the credible scientists understand nearly all of the effect is associated with sun cycles and these are thankfully out of the reach of Halliburton for now). Data from non-urban sources confirms the overall cooling trend, while urban heating continues to be a problem. If you really want to do something about it, quit living in the damn cities!
And according to these people, global cooling kills more people than warming (I can see the NYTimes correction now: Climate cooling, not warming, but Bush-induced cooling kills more than warming!)
And this cooling trend isn't a new phenomenon that can be "blamed on Bush" - unless you want to include Clinton, Bush Sr., Reagan and (gasp) Carter this cooling has been happening since 1975. Pretty interesting that the NY Times gets this wrong too. Then again, when the media feels it appropriate to run forged documents provided by mentally unsound oddballs that every expert consulted says are fraudulant, should we be surprised?
miniscule amounts of CO2 we pump into the atmosphere
Since the industrial age has begun, the amount of atmospheric carbon dioxide has increased from around 280ppmv to 380ppmv. You can argue about the effects of that carbon dioxide, but this does not strike me as a "miniscule" change; we've modified the carbon dioxide in the entire planet's atmosphere by almost a third!
The fact that humans can have such a drastic effect on an entire planet is pretty amazing.
Even the most complicated computer models for weather systems can only approach less than 5% of the actual variability and density of the atmosphere. Consider that most forecasts are less than 50% accurate at 48hrs+. I am not dismissing the research, far from it, I just don't think the models are there yet.
And they never will be. Period. This is the result of imperfect models and imperfect initial conditions. Even though your model was "perfect", uncertainty in your initial conditions will cause large error growths by some time. This is one aspect of chaotic systems....
That being said, one should keep in mind that climate models do not forecast the wather into the future. They do not attempt to forecast the weather on Jan. 26th 2043. What we call weather forecast is an attempt to model the weather systems (low pressures, high pressures) on short time scales. At best, the position and intensities of these systems can be modeled with some accuracy. For climate simulations the positions and intensities of weather systems are of less value, it is the statistics of these weather systems which can be described.
To me it seems natural that the intensities of hurricanes will change as a result of any global warming, since the intensity of hurricanes are closely linked to ocean surface temperature (evaporation is the primary energy source for tropical hurricanes).
Having lived through the recent series of storms here in Florida I can say first hand it is not any fun. This is the worst set of storms that central Florida area has had in the 30 years I have been here. I am not looking forward to more hurricane seasons like this one. This season I fared fairly well. I had a generator and transfer switch installed to power the house. Did that back in February, great timing for me. Went many days without commercial power during the storms this year.
Global warming may be a major factor. It is debatable if humans are responsible for global warming or not. (I expect this to get me modded down by the tree huggers.) What people need to realize is that change in the environment is constant. The last couple of thousand years things have been mild enough for humans to not only remember how things have been in the past but allowed us to develop the scientific processes that have allowed us to understand a lot of what is going on. We don't understand it all but we are working on it.
The big thing is to recognize that the earth is not a static diorama that never changes. It has gone through major weather cycles in the past and will continue to do so until the ultimate when the Sun goes nova. I personally doubt that people have as big an effect on the climate as some would like us to believe.
As things change people will adapt or find ways to adapt the environment to them. It is the way it has always been. If people survive for the next 10,000 years then we might figure out how to control the weather patterns. But hopefully we will be smart enough by then to know that we should leave well enough alone. And by that time we should have established self sustaining colonies off planet. So if the Earth becomes less than hospitable for us we can continue else where.
Another thing to remember, is if and when we try to control the weather, and that includes trying to fix global warming, we are more than likely going to cause more problems than what we had to start with. Remember, the job will go to the lowest bidder. And I expect the weather control stations will have the normal set of defects and shoddy workmanship which will lead to break downs and control problems.
ozone depletion actually reduces global warming
m
I don't think so. Ozone reflects radiation. Near the earth's surface, that's a bad thing because it keeps heat down. In the upper atmosphere, it's a good thing because it keeps far more heat out.
"Ozone reflects light in the upper part of the stratosphere, and thereby has a cooling effect. However, ozone in the troposphere acts as a greenhouse gas, and has a direct warming effect."
http://www.grida.no/inf/kurs/themes/ozon/ozon4.ht
Textbooks and Open Educational Resources
Back to the topic of coal fires, they only "produce about 2-3% of the total world carbon dioxide", while the US produces around 30%.
I'm sorry, the number you have dialed is an imaginary number. Please rotate your phone 90 degrees and dial again.
(Kerry voted against the Kyoto agreement in the Senate in 1998)
You know, I've seen so many Republican talking points that come in the form of "Kerry voted against X", that turn out to be based on procedural details and similar bullshit. So I did some Googling and found this article from December 1997 (smothered in an avalanche of right wing blogs essentially parroting what you said). In January 1998 the Senate voted 95-0 against Kyoto because the exemptions for developing countries were widely viewed as unfair.
There was recently a well regarded Climatalogist from Colorado that stated that global warming woulg actually have the reverse effect and lessen hurricane season. Who to belive? All I know is that I don't have a great deal of trust in the Times. Thier agenda seems to track more along the lines of fear mongering than full and balanced research.
Interestingly, of course, even if increased solar output or whatever else is causing the global warming (and these theories are being looked at and discounted by very respectable scientific reviews), the correct response is the same -- increase the IR transmittance of the atmosphere by decreasing the levels of CO2 and various other gasses to allow the Earth to lose heat faster.
The 30ish year hurricane cycle is well established, but global warming cuts across that -- if the sea is generally warmer there will be more hurricanes compared to the same point in the 30 year cycle when the sea is cooler.
"Increasing the overall thermal energy of the planet can only make them more probable. "
Not exactly. Hurricanes are fueled by convection so they need warm ocean surface temperatures and considerably cooler temperatures aloft. Warmer temperatures aloft don't support convection as well and will either lead to weaker or fewer storms. Also, during years of El Nino warm conditions in the Pacific, the upper level wind shear is less favorable for hurricane formation. All this shows is that weather is much more complicated than just "more thermal energy = more hurricanes".
Check out this faq for tons of info on hurricanes and tropical cyclone prediction.
Mod parent up. Kerry authored an ammendment to the bill:
KERRY (AND CHAFEE) AMENDMENT NO. 987 (Senate - July 24, 1997)
[Page: S8101] GPO's PDF
(Ordered to lie on the table.)
Mr. KERRY (for himself and Mr. Chafee) submitted an amendment intended to be proposed by them to the resolution (S. Res. 98) expressing the sense of the Senate regarding the conditions for the United States becoming a signatory to any international agreement on greenhouse gas emissions under the United Nations Framework Convention on Climate Change; as follows:
On page 4, line 13, after `period,' insert the following:
`(ii) provides countries with incentives and flexibility in reducing emissions cost-effectively by using the market-oriented approaches of emissions budgets, emissions trading, and appropriate joint implementation with all Parties,
`(iii) includes credible compliance mechanisms, and
`(iv) provides appropriate recognition for countries that undertake emissions reductions prior to the start of the mandated reductions;'.
Ask me about my vow of silence!
Haiti was grazed by a tropical storm (not strong enough to be called a hurricane) and around 2000 people have died with another 100000 or so left homeless and starving
A lot of this has to do with the rampant deforestation in Haiti. Notice that the Dominican Republic, which is on the same island, did not suffer nearly as badly, as it still has much of its forest remaining. There's a picture where you can pretty clearly see the border of Haiti and the DR -- DR is green, and Haiti is not.
You can never go home again... but I guess you can shop there.
It sounds like you're skeptical of simulations themselves. Remember, a simulation is just the numerical solution of a bunch of equations. The equations are physical laws involving heat, irradiation, evaporation, convection, etc., and the numerical solutions should indeed describe the real world, within a certain level of confidence.
Every time a tank gunner fires a shot, a computer runs a simulation---accounting for air resistance, winds, even the Coriolis effect---to figure out where the shell will land. Don't worry, though, it's describing where the shot could land if the Earth continues rotating.
And, CO2 is increasing, so that's the most useful thing to put into the simulations, no? Another post backs up the 1% number---the scientists didn't just make that up. But, if that is a bit too speculative for you, perhaps they can run another simulation under the assumption that an extraterrestrial carbon-neutral energy source will be unveiled at Area 51 in early 2005.
Also, please see http://www.wunderground.com/education/haiti.asp and the Florida Sun's interactive article (flash required) linked at the end.
DRM = Digitally Restricted Media. This is a viral sig, pass it on.
It describes what could happen were CO2 concentrations in the atmosphere to increase by 1% annually. I don't know whether this is actually the current trend.
1% annual increase of CO2 has indeed been the trend over the past 40 years.
It took me 15 secs to find that link via google. Maybe you should have spent these to avoid humiliating yourself...
Kerry voted against Kyoto? Gee, that's pretty amazing considering the Kyoto protocol was never submitted to the Senate for ratification.
Kerry had some problems with that version of the protocol but he definitely recognizes that we have to do something about global warming. That's why he has authored legislation to cut down on greenhouse gases.
Here's a quote from him on Kyoto:
"Bush's abrupt and unilateral decision to abandon discussions with the world community on climate change was early evidence of this Administration's misguided approach to dealing with the community of nations. Dropping out of international implementation of the Kyoto Protocol was foolhardy then, and it is even more obviously foolhardy today."
And here's some info on his legislative efforts regarding global warming:
Compare Kerry and Bush's environmental policies
Kerry and Bush sharply divided on response to global warming
Excerpt from the Seattle Times article:
"Kerry, like Bush, opposed American participation in the current Kyoto treaty. In 1999, he joined in a 95-0 Senate vote that stated that the United States should not ratify the treaty unless China and other rapidly developing countries were also required to reduce greenhouse gases.
But Kerry, who has called pollution a "mortal threat" to the climate, wants to reopen the Kyoto negotiations to refashion an agreement acceptable to the United States.
And even without U.S. participation in the treaty, Kerry has backed mandatory efforts to control carbon dioxide.
His most high-profile effort was a 2002 bill that he and Sen. John McCain, R-Ariz., submitted to the Senate to force automakers to improve automobile efficiency.
The bill would have required that average fuel economy for autos sold in the U.S. to rise from 24 mpg to 36 mpg by 2015. Lower fuel consumption would reduce greenhouse-gas emissions.
That bill was opposed by the U.S. automotive industry and automotive unions, which argued that the target was too extreme. It failed to pass the Senate.
Kerry also supports at least modest federal caps on U.S. emissions of greenhouses gases, such as the caps contained in legislation submitted to the Senate last year by McCain and Sen. Joe Lieberman, D-Conn.
That bill seeks to ensure that the overall U.S. emissions in 2010 would be no higher than the overall levels back in 2000.
The Coriolis effect is one factor in shaping cyclic convection currents. The sun itself is a factor - solar warming is an energy source that has a built in gradient, and so creates the potential difference in this case. Even a slowly rotating or even non-rotating earth would have the same potential for heat to flow from the hottest parts to cooler ones. However, the exact speed at which heat would be transferred would vary widely in such cases.
Remember, convection isn't a true zero sum game by itself. If heat is carried away more slowly from warm areas, they also radiate heat back to space at night faster to help balance out. If the ocean currents move significant warm water out of the hottest areas in less than a full day's rotation, they cause more mixing with cooler water and move it too, doing their work lesss efficiently, so only the average amount of energy transfered has to equal the average amount the sun dumped into the area. Even things like cloud cover and the resulting local albedo are part of a series of feedback loops that makes this system meta-stable.
Planetary rotation tends to make lots of little interlaced convection cells into a few big ones, but various features, like submarine topography, how steep the thermal gradients become, and probably even 'chaotic' effects, all let the system switch between meta-stable modes.
Climatologists mostly hope thae 'chaos' effects aren't as significant as they are for weather, because the butterfly effect stops sounding as cool when it's " A codfish farts, and two weeks later..." instead of pretty stuff that Jeff Goldblum can use for pick up lines.
Unfortunately, the geologic record shows some of these modes seem to include ones where the gulf stream flattens out a lot towards the equator, or breaks away from either the European or North American coastlines so that it becomes more triangular rather than extending to about the same latitudes on both sides. This is based on such measurements as thickness of sedements deposited in the same layers, and types of fossil species found during ice ages, so there's some guesswork included, but it looks like the way to bet.
Since some of the planetary heat transfer processes don't go fast enough to keep up with the 24 hour warming and cooling cycle, or even the seasonal ones, Those areas where slow transfer rates predominate can get hotter or colder even though the average isn't moving the same way. If the system was actually getting close to equilibrium at any point, the seasons wouldn't lag months behind when the planet is closest to the Sun.
Who is John Cabal?
Long range weather forecast is still an open research topic. There is a weather simulation project called ClimatePrediction.net where your computer simulate 15 years of the earth climate while you get a cool looking screen saver with the simulated weather.
Their goal is to have the most accurate weather forecast model around. This should lower the uncertainty and clear up this question of CO2 and how much it contributes to global warming They are calibrating with simulation of past weather. With the calibrated models they will then forecast the next 50 years and hopefully this will tell us if hurricanes become more likely.
Join in numbers and help clear up doubt about the future climate.
http://www.gfdl.noaa.gov/~tk/ Thomas R. Knutson is from the government and he's here to
help you while he helps himself to some more pork.
http://www.okpork.org/
I'd go on a Vegan diet but the delivery time from Vega is too long. --brownkitty
In fact, it's damn near ridiculous. These arguments always are.
I'm not making an argument; I'm presenting evidence, gathered by NASA, measured several different ways, all of which agree.
You, on the other hand, are an anonymous coward making some unsuppored claims that disagree with all published data I've ever seen. Very convincing of you...
In any case, look for the phrase "Comparison of CO2 emissions from volcanoes vs. human activities." on this USGS page. Or you can choose any of the other pages you find on volcanic CO2. If you're too lazy to read it, let me summarize it: humans add about 100x the CO2 to the atmosphere than volcanos do.
Obviously depends on how much the Sun is increasing. I believe that global average temperature is 10 or 20 Kelvins more than it would be if there was no greenhouse at all, so there is some way to go.
As you say hurricane records are pretty spotty, but the basic connection -- warmer sea surfaces leads ot more and bigger hurricanes globally is pretty clear. Some places might end up with fewer and smaller because of some weird feedback effect, but overall, that heat energy needs to be moved and a hurricane moves a lot of it.
Hurricanes are heat engines driven by the energy contained in warm surface water. As the winds pick up, they are able to suck more and more of the energy from the sea surface. Because there is a limited supply of warm surface water, they need to keep moving to continue to grow.
In many ways, they are like wildfires burning through brush. The heavier the brush, the more intense the fire. If there is global warming, it will certainly lead to increases in mean sea surface temperatures, which increases the energy available to storms such as Hurricanes, therefore, bigger hurricanes.
While many aspects of global warming, like the rate and the detailed effect it will have on different regions is controversial, saying that global warming will lead to more intense hurricanes is not controversial.
I've been a bit of a skeptic about global warming for years. The chicken little crowd has always bugged me. But, if you turn off the politics and look at the data you see that currrent C02 levels are the highest in the last 150K years and are rising every year. This is a dangerous experiment we are doing with our atmosphere.
If reducing CO2 was going to cost lives or billions of dollars, then it is debatable whether we should do it. But, the things you'd do to reduce C02 like driving more efficient cars, buying more efficient appliances, insulating your houses, etc. are things we should do anyway, for other reasons - reduce polution, dependence on foreign oil, and on a micro scale, save everyone money.
My $.02
-DT-
If only climate prediction were so predictable that someone with (big assumption on my part) no formal advanced training in climatology could make such broad assertions with such certainty. I don't have any advanced formal training in climatology but I don't think that you do either.
First, yes warm water is the fuel of a hurricane, but the assumption that you make that "it doesn't encouter any upper level troughs or other shearing mechanisms" is a huge assumption. If you are someone who lives in a hurricane prone area, like myself and many other millions, you are made aware of certain facts. The first is that small changes in climate in one area of the earth has a massive affect on the climate on another area of the earth. El Nino is the classic example. El Nino leads to far fewer hurricanes because the warm water in the Pacific causes different upper level wind patterns (i.e. shearing) in the Atlantic (not to mention all over the world). I am sure that you knew this because you made the assumption about shearing in the first place. My point is that this is a huge huge assumption.
Secondly, most models suggest that the temperate regions will have the greatest affect by global climate change. This means that your reference to the equitorial region warming is another huge assumption.
Third, we have for the past several decades had substantiall fewer hurricanes in the Atlantic and Carribean and Gulf than the statistical average. That happened during those years of "global warming". Why have the number of hurricanes been lower than average during years that many scientists say the temperature went up? 2 reasons, climate is very very difficult to predict and hurricanes are very very difficult to predict (meaning hotter does not necessarily mean more). You cannot use static analysis on whether.
Hurricane experts, for the past couple of years, have been saying that the number of hurricanes is going to climb back to the historical normal level and that people are going to be surprised because they are used to the hurricane lull. They have not been saying this because of global warming, they have been saying this because of the natural hurricane cycle.
This whole thing reminds me of that summer when there were some high profile shark attacks. The press declared the current year as having a epidemic of shark attacks. They spent many many words editorializing on the cause of this massive increase (global warming was implicated I think). The number of shark attacks for that year turned out to be fewer than the average. It was just alot hype from the press.
I have no clue whether or not there is substantial global climate change or an increase in the number of hurricanes as a result, but I do know there is alot of hype and conjecture.
Which is why thaey cn predit increased intensity of hurrricanes (largely climate-induced) but not frequency (much more dependent on imeidate weather events).
In fact there is substantial dispute as to the nature and causes of climate change. Those curious might check out these websites: http://www.co2science.org/ http://geography.asu.edu/balling/
There are only 6,863,795,529 types of people in the world.
One, we not only withdrew from the 'protocol' (the treaty) we withdrew from the negotiating body that is still working to define future 'protocols.' I said that in my post; we withdrew from the PROCESS. We withdrew from having input into future proposed treaties. Two, on a per capita basis (or national basis, for that matter), the US emits MUCH more carbon than China and India. They were exempt precisely because their per capita emmissions are relatively very low compared to ours. The opposition was because it targeted the US as the major emitter of carbon, and that would hurt our economy. The Kyoto treaty was flawed, and could not have been ratified. But the process for modifying that, and working toward a more palatable treaty was extant, and Bush withdrew from THAT.
Denial of unpleasant truths seems to be a big part of living in Western culture.
Every fifth post through this whole thread is, "The Sky is NOT falling!" and "There is NO link between global warming and strange weather!" Essentially, "NOTHING IS ABNORMAL! LA LA LA! I CAN'T HEAR YOU!"
Ahem. .
First Ever South Atlantic Hurricane Hits Brazil. (March of 2004)
South American Glaciers Melting Faster, Changing Sea Level.
Alaskan Glaciers Melting Faster.
desertification in China.
desertification in Africa.
.
Heck, even the rest of the solar system is acting funny. Remember the. .
Blue Band on Jupiter this past March of 2004?
and
the Huge X-class solar flares of last year?
Interestingly, the evidence of past hurricanes categorized by decade suggests that there have been big hurricanes to make US landfall before. Indeed, the worst decade, from 1950-1959 saw a total of nine storms between category 3 and 4, (though none of category 5) during that ten year period. Sure. But we've just had four in just one summer. Nobody can say that this is par for any course.
Now, I am not claiming that this has anything to do with global warming. But anybody who tells me that everything is normal probably swore up and down that The Phantom Menace was a good film for a whole year after it came out.
-FL
First post ever, my apologies if I foof up the links.
True, the Gulf Stream is a western boundary current (the Brazil, Agulhas, East Australian and Kuroshio Currents are as well). They are a "return" current caused by wind driven currents and the coreolis force. For example, in the Subtropical North Atlanic (Below 45 degrees N or so), the prevaling winds blow from west to east ("the westerlies"), which causes an equatorward drift. The Gulf Stream is the return flow of that drift "bunched up" on the western side of the the Atlantic. A bit of an oversimplification, you can read a bit more here.
The thermohaline circulation is related to deep circulation. In the North Atlantic (the Labrador, Norwegian and Greenland Seas), water can be cooled very rapidly during winter, which sets up convection cells - when cooled, the water becomes more dense and starts to sink; the formation of ice also removes pure water and increases density. So the cold, salty "deep water" sinks down (to somewhere between 1000 m and the bottom - about 4000 m), and drifts equatorward , underneath the gulf stream. That deep water is thought to make its way to the Southern Ocean, and around into the Pacific and Indian Oceans, where it eventually upwells. Deep water moves slowly, but is the counterpart to surface circulation (and there's a lot of it). This theory was put forward by an Oceanographer named Wally Broeker, who called it the "global conveyor belt" - it is thought to be very important for moving heat around.
There is some evidence for rapid climate changes in ice core records, and some have speculated that the conveyor belt could be shut down (a la The Day After Tomorrow), which had some pretty hilarious science, climate-wise). There is some geochemical evidence that it has happened in the past - for instance there's some evidence that two massive lakes filled with meltwater from the last glaciation drained into the North Atlantic over a very short period (following the failure of a massive ice dam) about 8200 years ago. The idea is that a surface layer of very fresh (i.e. low-salinity, hence low density) water, would "cap" the deepwater production areas. If it's already pretty fresh, ice formation wouldn't increase the salinity as much (and density is mostly from salinity, not temperature) - thus requiring much more cooling to make new deep water (which would be exacerbated by any warming). At some point deep water would not be created, and since the water from the Gulf Stream must go somewhere, it would "pile up" in the North Atlantic, eventually disrupting or stopping the Gulf Sream.
Obviously there aren't any glacial lakes that we need to worry about suddently draining into the North Atlantic, but the idea is that increased inputs of fresh water would eventually reduce the amount of deepwater formation. That would take a fairly large amount of warming, but is possible (~ a 20% chance in the next 50-100 IIRC). I'll refer you to a good article on the topic by Wally Broeker. It's five years old now, but still pretty much on the money. I'll refer you particularly to his figure 5.
Sorry also for my "excessive" use of "quotation marks" - bad habit.