The Gulf Stream Slows Down…Trouble Ahead?
By Justin Gardner | Related entries in Environment, The WorldRemember that silly movie The Day After Tomorrow?
Well, if you don’t, it imagined a future where the Gulf Stream simply shuts down. The resulting scenario is a new Ice Age in a VERY short period of time. Okay, well, even scientists who study the Gulf Stream say the movie’s timetable is ridiculous, but the scenario itself is not.
Here’s a little background:
The gulf stream is one of the strongest ocean currents in the world. It is driven by surface wind patterns and differences in water density. Surface water in the north Atlantic is cooled by winds from the Arctic. It becomes more salty and more dense and sinks to the ocean floor. The cold water then moves towards the equator where it will warm slowly. To replace the cold equator-bound water, the gulf stream moves warm water from the Gulf of Mexico north into the Atlantic.The gulf stream brings warmth to the UK and north-west Europe and is the reason we have mild winters. The average annual temperature of north-west Europe is about 9C above the average for our latitude.
At the end of the last Ice Age, when the ice sheet covering North America melted, the sudden increase in fresh water reduced the salinity of the north Atlantic surface water and therefore less ‘dense water’ sank and moved towards the equator. This reduced, or even shut-down completely, the warm gulf stream. Temperatures in north-west Europe fell by 5C in just a few decades
And now we have further proof that the Gulf Stream is slowing down…
Researchers on a scientific expedition in the Atlantic Ocean measured the strength of the current between Africa and the east coast of America and found that the circulation has slowed by 30% since a previous expedition 12 years ago.The current, which drives the Gulf Stream, delivers the equivalent of 1m power stations-worth of energy to northern Europe, propping up temperatures by 10C in some regions. The researchers found that the circulation has weakened by 6m tonnes of water a second. Previous expeditions to check the current flow in 1957, 1981 and 1992 found only minor changes in its strength, although a slowing was picked up in a further expedition in 1998. The decline prompted the scientists to set up a £4.8m network of moored instruments in the Atlantic to monitor changes in the current continuously.
So what could this mean?
The network should also answer the pressing question of whether the significant weakening of the current is a short-term variation, or part of a more devastating long-term slowing of the flow.If the current remains as weak as it is, temperatures in Britain are likely to drop by an average of 1C in the next decade, according to Harry Bryden at the National Oceanography Centre in Southampton who led the study. “Models show that if it shuts down completely, 20 years later, the temperature is 4C to 6C degrees cooler over the UK and north-western Europe,” Dr Bryden said.
But thankfully, it doesn’t seem like we’ll get a “The Day After Tomorrow” scenario anytime soon…
Although climate records suggest that the current has ground to a halt in the distant past, the prospect of it shutting down entirely within the century are extremely low, according to climate modellers.
Interesting stuff. Still more thoughts from the New Scientist.
What are your thoughts?
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December 1st, 2005 at 9:50 am
Media Alert: Paula Zahn, CNN Tonite
Rush Limbaugh led off his show today with the altercation between Charmaine Yoest, Ph.D., Fellow at the Family Research Council and Kim Gandy, President of the National Organization of Women in The Nation’s Capital. There was no blood. But it…
December 1st, 2005 at 11:24 am
One paragraph from the New Scientist article says it all:
Richard Wood, chief oceanographer at the UK Met Office’s Hadley Centre for climate research in Exeter, says the Southampton team’s findings leave a lot unexplained. The changes are so big they should have cut oceanic heating of Europe by about one-fifth – enough to cool the British Isles by 1°C and Scandinavia by 2°C. “We haven’t seen it yet,” he points out.
So, either the gulf stream really isn’t slowing down, or at least not significantly, or else the relationship to European temperatures isn’t understood that well. In any case, there is no evidence of anything devastating at all. Typical end-of-the-world hysteria on the part of the Guardian.
December 1st, 2005 at 11:31 am
No. It just means some scientists disagree.
And really, you think it’s hysteria to worry about the Gulf Stream shutting down? Listen, they could be wrong, but I’d rather be wrong and concerned, then right and unconcerned. The cost is simply too great to ignore.
December 1st, 2005 at 12:12 pm
I know this is not going to fit into your preconcieved notions, but visit this link anyway: http://www.wunderground.com/education/abruptclimate.asp
December 1st, 2005 at 12:37 pm
Very interesting. Thanks for sharing that Jim. Again, I think it’s better to be concerned and wrong, than the reverse.
December 1st, 2005 at 12:53 pm
Lousy liberals, with your “science” and your “caution”.
December 1st, 2005 at 1:04 pm
Your welcome, Justin.
Oops, is politeness allowed on blogs?
December 1st, 2005 at 2:20 pm
Nice one Dada.
Actually Jim, that’s more the rule around here, not the exception. Imagine that!
For a funny look at how Gateway Pundit proves the need for a site like ours, read here, and then read the very last comment where one of his own readers questions why he called our site “far left.”
December 1st, 2005 at 4:20 pm
And really, you think it’s hysteria to worry about the Gulf Stream shutting down?
Of course not. A 9c temperture drop in Europe would be devastating.
However, I think it’s hysteria to publish an article proclaiming the imminent threat of a 9c temperature drop in Europe when anyone with a thermometer and a log book can prove it isn’t happening. It’s scientifically unethical to take your pet theory, which is demonstrably false, and parade it to the news media as an impending disaster. I say this as a physics major, BTW.
Could a 9c drop still happen? Of course. Does this study provide convincing evidence that it’s about to happen? Nope. It’s an interesting data point, not an looming crisis.
December 1st, 2005 at 4:28 pm
I was reading the thread on RedState about this, and it astounded me the amount of denial those people kept spewing. To totally ignore 99+% of the relevant scientific community’s conclusion that global warming is and has been occurring, and the multitude of projections that range from bad in 100 years to horrendous in 30, seems very much like a red ostrich sticking its head in the tar sands.
I don’t personally believe we will see any immediate climate changes, but I do believe the oceans are becoming saturated with carbon, and once their buffering limits are reached all of the CO2 they have been removing from our energy waste stream will concentrate rapidly in the air, causing potentially disastrous short term consequences (climactically a decade or two is short term).
I do expect to see rising sea levels due to melting antarctic glaciers within 10 to 30 years, though if the above referenced article is correct Europe may counter that somewhat by sequestering water in glaciers on its mountains and hills, and perhaps even over its cities. The other good news about this is it may preserve the icecap over Greenland, which contains enough water to raise global sea levels by 7 meters.
Another interesting question that I haven’t seen asked yet is whether the slowing of the gulf stream has anything to do with the severity of the hurricane cycle this year. As the flow of cooler water from the north continues to slow, the equatorial waters will likely heat up, providing far more fuel for storms and hurricanes than existed in the past.
This trend, additionally exacerbated by global warming, could eventually make most of the gulf and southern Atlantic coastline uninhabitably expensive due to frequent rebuilding needs – consider if you will a constant trend of 2-5 Rita’s a year at random places from southern Mexico to North Carolina.
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The biggest problem with Bush’s approach is that he seeks to minimize the problem, as well as minimize any impact to his oil buddies. Hence most of his proposed solutions are inadequate and are very likely to have little to no effect on the problem. In addition, he keeps making many of his measures voluntary, which means they are totally countered by free market economics. Given the choice between a polluting option that saves 10% cost and a non- or lesser-polluting option at full price, guess which one companies will produce and people will buy?
What needs to be done *immediately* is to seek (nonpartisan) scientific and economic consensus on the best and most cost-effective ways of reducing greenhouse gas emissions. Many of these options are quite available and cost-effective today. Such actions could include, but are not limited to:
- Require emissions and fuel economy standards on vehicles that do more than incrementally nudge current efficiency. Asian carmakers are already far ahead of Americans in this realm (due to more stringent requirements and environmental concerns), so we know it’s possible. Hybrid cars can now yield easily two to four times the fuel efficiency of current cars – give bigger tax incentives to both consumers and producers, and shift taxes to lower efficiency vehicles. Currently available lighter-weight materials also provide huge gas mileage increases. Various other technologies, such as continuous transmissions, also increase gas mileage using currently available technology, but are resisted due to the retooling they would necessitate. Increasing fuel taxes gradually would also have the economic effect of increasing demand for fuel-efficient vehicles.
- Back off on the fuel cell push. Fuel-cell cars are as yet a dream at least 20 years out, and are a smokescreen used to give automakers time to continue producing the same polluting vehicles they are making now. In particular, hydrogen storage methodologies adequate for vehicles are barely in experimental phases, the metal catalysts required in most designs are extremely expensive and not available in the required quantities, and hydrogen itself is generally produced using greenhouse gas-emitting methods, and it is also itself a greenhouse gas that could have consequences if leaked from millions of vehicles worldwide.
- Phase out grandfather clauses for dirty power production and other facilities, instead of enhancing them as Bush did. I read that a small percentage of power plants in the Northeast produce something like 80% of all power plant pollution in that region.
- Strongly encourage green alternate energy sources, such as solar and wind, and seriously investigate the feasibility and safety of modern or next-generation nuclear reactors, such as the pebble bed variety.
- Encourage greener appliance and discourage less green appliances via incentives and taxes. This should include plugging up the power drains of “always plugged in” appliances such as VCR’s, TV’s, and microwaves. Research and market encouragement for technologies such as magnet-based refrigerators (supposedly much more efficient and less polluting than current models) should also be encouraged.
- Enhance research and encourage production of LED lighting. These have a huge potential in energy savings, yet can last for decades, and are fairly close to marketability now.
- In particular, assisting developing countries to build cleaner power plants to meet their energy needs is crucial. China and India are covered by a huge blanket of pollution, which will only get worse as they continue to build dirty coal power plants.
December 1st, 2005 at 4:37 pm
BrianOfAtlanta – first of all, it was a 5-7C temperature drop, or approximately 10F, and it was suggested that it might occur in 10-20 years after the stream shuts down. Considering it is just now beginning to shut down, it is premature and irresponsible to suggest that it isn’t happening at all just because the predicted result of such a change has not yet occurred.
Since this is the first study of this phenomenon, as with all scientific endeavours, you should rate the results as to whether they are interesting and/or concerning enough for followup study, and temper that assessment by the reputation of the scientists involved and the professionality of their effort.
It seems to me that there is no question that significant further study is warranted, along with some form of permanent measuring system that can track seasonal changes in patterns in various areas within the Atlantic. Of course it is possible that the stream has merely shifted east or west, or that some temporary condition caused the perceived change, but it would be better to know that than to have all of Europe blasted, totally unprepared, in 10 years by a fairly radical climactic shift.
December 1st, 2005 at 5:26 pm
Amazing how we’ve managed to blame the possible fading of the Gulf Stream on man-made global warming and George W. Bush’s energy policy. Bejeezus, does anybody study anything anymore?
The problem with the Gulf Stream slowing and hurricanes is not that it reduces the amount of cool water flowing down the coast of Africa — that water, being cool, is at the bottom of the sea. Hurricanes form on the surface.
The problem is (or would be) that less heat is being drawn off from the American tropics, thus allowing hurricanes to gain a little strength.
But none of this means anything withiut reference to the jet stream. If you really want to change the climate, and the storm pattern, you have to jigger both the ocean currents and the winds. Complex, isn’t it? Which is why even scientists have a hard time really agreeing on effects and causes, even if they agree on data. Best to leave the politics out of it. It’s tangled enough already.
December 1st, 2005 at 5:56 pm
Actually it is not his policy that caused it, but he is certainly doing absolutely nothing to even try to abate it, and likely will exacerbate it. The science is suggesting that the fading of the gulf stream is due to an infusion of freshwater in the north, likely caused by polar and greenland melting. This of course is due to a combination of the polar ozone hole and global warming, both at least in part caused by man-made pollution.
Of course the water is on the bottom of the sea, but having supposedly studied, I’m sure you are aware that with a warm layer above and a cool layer below that heat diffusion causes the temperatures to level out over time, hence the loss of the cooler water from the north will have the net effect of warming the equatorial waters.
Agreed that the science is quite complicated, and that the exact repercussions and effects are not truly known yet. However, it is almost certain that it will have SOME effect, and likely a bad one. Unfortunately, many politicians use the uncertainty of some of the scientific details as carte blanche to assume that all of the science is worthless, and that nothing is happening, and thus nothing seems likely to be done about this problem until it is way too late.
December 1st, 2005 at 6:20 pm
The point that perhaps we all can agree on is, that, having adapted ourselves and our infrastructures to the current set of climate conditions, any change in those conditions, whether through human agency or natural cycles, would be detrimental and probably catastrophic for us.
What’s the estimated fresh water runoff increase from Greenland? I’m having a hard time thinking it’s enough to kill the Gulf Stream in just a few years. The last big rush of fresh water up there came 8,400 years ago when the glacier dam collapsed that held back what is now Hudson’s Bay, and about 163,000 cubic kilometers of water gushed into the North Atlantic.
That’s about 30 percent more water than is contained in all of the world’s lakes today, and it was enough to raise world sea levels half a meter or so. It set off another cold spell. But I can’t imagine Greenland melting is anywhere near that level.
December 2nd, 2005 at 3:47 pm
The north polar icecap has been melting at a fairly fast rate. That, plus the Greenland runoff combined may be enough. Greenland has enough ice on it to raise worldwide sea levels by 7 meters, so it’s pretty significant.
According to this: http://www.timesonline.co.uk/article/0,,2087-1602579,00.html the polar icecap has become 46% thinner over the last 20 years. Of course since most of the polar icecap is floating freely, this will not affect sea levels at all.
I couldn’t find any articles quickly about how much the Greenland icecap has contributed, but here: http://www.terradaily.com/news/iceage-05r.html is an article which discusses how outlying glaciers surrounding Greenland have been receding (and thus dumping in more freshwater), much like they have in Antarctica. This Huffington Post article: http://www.huffingtonpost.com/2005/11/20/greenlands-ice-caps-tu_n_10956.html also has some interesting discussions on the topic.
Another interesting article is here: http://dspace.dial.pipex.com/ritson/earth/water/ which says that the IPPC’s best estimate for sealevel increase is 18 cm by 2030 and 44 cm by 2070, but that assumes “business as usual” with carbon dioxide levels staying at today’s level, and no shutdown of the gulf stream. Presumeably those figures would be much higher if the predicted CO2 increase were included.
However, if the gulf stream shutdown occurs, that actually may cause reduction of sealevel, since glaciers in Greenland and Europe would likely suck up at least some of the excess water.
That’s one of the reasons this whole topic is so difficult to figure out precisely…sometimes the same factor can cause both warming and cooling effects, many factors are interrelated, and determining the contribution of each and the net sum of all those factors takes humongous supercomputer runs, which can still be wrong if unknown important factors are ignored. For example, increasing temperatures cause increased cloud cover, which has a higher albedo than land, and thus reflects more heat back out of the atmosphere. Even things such as plane travel can cause complications, because jet trails can effectively “seed” clouds and increase cloud cover.
That having been said, however, many of those supercomputer runs HAVE been completed, and most of them paint a pretty bleak picture of the future – especially the ones where we continue as is with no or little effort to even attempt to limit emissions growth.