CURRENT QUESTIONS A key aspect of the Atlantic Ocean's large-scale circulation involves the sinking of cold, dense water--called deep-water formation--in Arctic and Antarctic waters. Scientists who are trying predict how climate change will play out in different parts of the globe want to find out how this vital circulation is altered in a warmer, wetter world--and how this alteration in turn will affect climate.
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Every second, a vast quantity of cold, dense seawater equal to six times the combined flow of every land river on Earth streams over an ocean-floor ridge that stretches between Greenland and Scotland. This deep southbound current, flowing from the Norwegian, Iceland and Greenland seas into the North Atlantic, is the lower limb of the Gulf Stream and its northerly extension, a great conveyor belt of ocean heat and salt that transports warm tropical water north from the equator. Most climate change models predict global warming will slow these flows, in part by altering a key component of the Atlantic's circulation, called deep-water formation. If that happens, northern Europe will cool—or warm less severely—as the rest of the globe swelters.
Understanding the role that deep-water formation plays in driving this grand circulation pattern, more formally called the Atlantic Meridional Overturning Circulation (AMOC), will help scientists predict how global warming will affect climate—both in and beyond the Northern Hemisphere. Shifts in the Atlantic's circulation patterns will alter African and Indian monsoon rainfall as well as hurricane patterns in the South Atlantic, resulting in "a profound impact on the global climate system," according to a team of international scientists asked by the U.S. government to evaluate the potential for abrupt climate change.
Oceanographers have been using moored acoustic Doppler current profilers and temperature sensors for the last decade to measure deep water as it pours over the Greenland–Scotland Ridge on its way south. They're both trying to establish the natural yearly and decadal variations in its creation as well as look for evidence of changes from human-generated temperature increases. "Our assumption is that when we are studying the exchange between the North Atlantic and the Nordic Seas, that this deep conduction and cooling of ocean water is important to the AMOC," says Svein Østerhus, an oceanographer at the Bjerknes Center for Climate Research in Bergen, Norway, who has been investigating the flows.
Deep-water formation is just what it sounds like: As the Atlantic's surface waters travel north they become cooler and denser, so that by the time they reach the Arctic they are cold enough to sink to the ocean bottom. The sinking water pulls warm surface waters like the Gulf Stream north, which in turn leaves a void that pulls deep, colder water south. If global warming inhibits the formation of deep water, the flows across the Greenland–Scotland Ridge should slow.
But it's not that simple. Between the 1950s and the 1990s, the deep water in the Nordic Seas was both warmer and increasingly less salty. As a result, "we had quite remarkable changes in deep-water formation," Østerhus says. Nevertheless, the flow of deep water headed south over the Greenland–Scotland divide has remained stubbornly stable for the past 50 years, Østerhus and his colleagues reported a paper in Nature late last year. The reasons for these counterintuitive findings are not clear, he says. It may be that deep water is pooling behind the Greenland–Scotland Ridge, providing a reservoir from which older deep water can flow when production is slowed. Østerhus's colleague, Detlef Quadfasel, an oceanographer at the University of Hamburg, thinks that part of the explanation is that "this is a nonlinear system—it can simply jump from one state to another."
Now Østerhus will travel in January to the other place on the planet where deep water forms—the Antarctic. The Weddell Sea off Antarctica is home to the coldest, densest deep water on Earth. Østerhus's mission will be to retrieve data from a string of high-tech monitors put in place there last February, with the hope of understanding how Antarctic deep-water formation affects the churning of the Atlantic's currents far to the north. There is very little information on deep-water formation in the Antarctic, and Østerhus will collect basic data on temperatures, velocities and salinity that will form the foundation for later comparisons.
"Deep-water formation in the Arctic and Antarctica are of equal importance, and they are linked," he says. "Deep water formed in the Arctic can be traced the whole way south to Antarctica and deep water formed in the Weddell Sea can be traced as far north as Ireland. A change in the Antarctic deep-water formation may have an impact on the circulation of the North Atlantic."
As Østerhus and his colleagues scramble to understand what's going on at the most distant edges of the Atlantic, roughly two dozen other projects are measuring the Atlantic’s flows elsewhere, including a string of instruments from the Bahamas to Morocco. And in late September an international team proposed that the entire network be transformed into a more formal international monitoring effort in the hopes of helping humankind prepare for what global warming will bring.
"We rely on climate forecasting models to understand climate change, but not all models are in agreement," says William Johns, a University of Miami oceanographer who helped write the abrupt climate change report for the U.S. government. "We have to refine these models to get some idea of what we are going to have to get adapted to—and exactly how much warming we will get in the North Atlantic depends on how much this circulation really does slow down."
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31 Comments
Add CommentSorry, if climate change deniers cannot see it - it doesn't exist.
Reply | Report Abuse | Link to thisWhat ever happened to global warming? I guess that's so 1998 when the temps stopped getting warmer.
Reply | Report Abuse | Link to thisHave you considered the way ice melting in water will maintain the temp at 0 while it melts, and only once it's gone will the temp rise? There's lots of ice on the Earth left to melt... doesn't mean we're not holding in much more heat because temps aren't rising yet.
Reply | Report Abuse | Link to thisInteresting about the 50s and 90s. I wish it would delve more into the effects the lower salinity had on those decades. It is worth reading more to find out about one of the least understood parts of this planet is affecting us. The Oceans.
Reply | Report Abuse | Link to thisNostradamus is predicting an ice age after the destruction
Reply | Report Abuse | Link to this"I guess that's so 1998 when the temps stopped getting warmer." - candide.
Reply | Report Abuse | Link to thisYet the temperature has warmed significantly if you use the years 1997 or 1999 as your starting point.
The fact that the select 1998 rather than the years on either side, or any recent year before 1998 indicates that you have cherry picked your starting point - which as it turns out was the second warmest year on record.
It is the same kind of lying as would be told by someone who sees an 8 foot tall man walk into a room followied by a 6 foot tall man and then claim on that basis that people are shrinking.
There is only one reason you would tell such a lie.
You fear reality.
"I guess that's so 1998 when the temps stopped getting warmer." - candide.
Reply | Report Abuse | Link to thisYet the temperature has warmed significantly if you use the years 1997 or 1999 as your starting point.
The fact that the select 1998 rather than the years on either side, or any recent year before 1998 indicates that you have cherry picked your starting point - which as it turns out was the second warmest year on record.
It is the same kind of lying as would be told by someone who sees an 8 foot tall man walk into a room followied by a 6 foot tall man and then claim on that basis that people are shrinking.
There is only one reason you would tell such a lie.
You fear reality.
The basic premise appears to be that humans are causing climate change yet there is not universally accepted theory and data supporting this contention. So little is known about the sun's role in this matrix and that of the ocean currents/conveyor belts that conclusions such as this are ludicrous and an example of extreme hubris.
Reply | Report Abuse | Link to thisActually it is pretty much universally accepted among climate scientists that humans are warming the planet. The sun does have a powerful affect, but solar output hasn't changed enough to account for the observed changes in the environment.
Reply | Report Abuse | Link to thisRegarding comments about the temperature since 1998: recently temperature data for the last decade or so was given to several independent statisticians, who were not told what the data represented, and they found no negative correlation, meaning average temperatures have not dropped even a little since 1998.
So why is everyone so concerned with the temp changes?? Temps would be the last thing to change! There's tons of evidence of, for instance, premature glacier melt.
Reply | Report Abuse | Link to thisSource: http://www.ted.com/talks/lang/eng/james_balog_time_lapse_proof_of_extreme_ice_loss.html
You can't tell me the heat going into melting this much ice/snow is inconsequential, even if the temps aren't changing.
It's called heat transfer system. The atmosphere, the sea, land and polar ice are constantly "transfering" heat between each other. The convergence area between each one of these relatively semi-homogeneus areas is the lithosphere, where we live. The stability we're having in our area is related to the heat transfer that is going on between the cold of the polar ice, the heat of the sun, and the heat that we are causing. The system is buffered by the water in it: the oceans. Considering that the cold generating part of the system is loosing it mass, by melting and turning into the "buffer mass" of the sea, the nonlinear relation will maintain stable until the cold generating part of the system stops cooling. Then, the temperature of the water will gain heat rapidly... that is when things will get really crazy.... we must be prepared.
Reply | Report Abuse | Link to thisOh no!! wait! we don't have time to think in these little things... we must make MONEY, and kill our enemies, and we must fear and obey our God or something... we are busy trying to collect money, to collect power and all material things that make us better than everyone else.... just to feed our greed... to feed our EGO. As soon as we understand the value of the interdependency relation that exist between all the beings of the specie as a colective interest; and learn that as a group we must focus our lives to the intelligent use of resources oriented primarily on the good of the community. Understanding that all the components of the system are necessary to maintain the balance, will put us towards the comprehension of how the system works, in order to manage it until we learn how to control our environment inside and outside the planet, and turn to the very root of all things.
It's called heat transfer system. The atmosphere, the sea, land and polar ice are constantly "transfering" heat between each other. The convergence area between each one of these relatively semi-homogeneus areas is the lithosphere, where we live. The stability we're having in our area is related to the heat transfer that is going on between the cold of the polar ice, the heat of the sun, and the heat that we are causing. The system is buffered by the water in it: the oceans. Considering that the cold generating part of the system is loosing it mass, by melting and turning into the "buffer mass" of the sea, the nonlinear relation will maintain stable until the cold generating part of the system stops cooling. Then, the temperature of the water will gain heat rapidly... that is when things will get really crazy.... we must be prepared.
Reply | Report Abuse | Link to thisOh no!! wait! we don't have time to think in these little things... we must make MONEY, and kill our enemies, and we must fear and obey our God or something... we are busy trying to collect money, to collect power and all material things that make us better than everyone else.... just to feed our greed... to feed our EGO. As soon as we understand the value of the interdependency relation that exist between all the beings of the specie as a colective interest; and learn that as a group we must focus our lives to the intelligent use of resources oriented primarily on the good of the community. Understanding that all the components of the system are necessary to maintain the balance, will put us towards the comprehension of how the system works, in order to manage it until we learn how to control our environment inside and outside the planet, and turn to the very root of all things.
I sure wish someone would come up with a study to see what might be the changes to the desertification in the Sahara and the U.S. Southwest deserts . Will the climates get wetter as the Ice Melts and the air proves to be more humid ?As more water is rained down upon the land will it get greener everywhere like during the early triassic period and will the O2 levels rise and precipatate an increase in Fauna sizes ?And lastly but not leastly will my property in northern Canada finally be ready to farm after all the pesky perma frost melts !
Reply | Report Abuse | Link to thisKeep it up and the system might consider you an Evil Genius !
Reply | Report Abuse | Link to thisgentlemen:
Reply | Report Abuse | Link to thisCould anyone here tell me what cools the Stratosphere, and quite especially the Tropopause, that seems to be the cold side or surface or envelope that encloses the globe. According to the books, 18 Km high in the tropes and 8 Km at the poles, with very strong "Jet- currents".
The books tell of temperatures from -50 to -60 Celcius even with the sun right in Zenith. My record in a Jumbojet from Frankfurt to Boston, waving between 11.8 and 12 Km high. and the temperatures outside were waving from -67 to-70! celsius, beat that! South of Island at bright daytime in October. Those temperatures are solidly below the winter frost records at night in Siberia. Conclusion: The poles do NOT! I Repeat NOT! cool that Tropopause because they are warmer.
The Gas- Law, the Barometric law do NOT cool it. The Joule Thomson- effect do not cause those low temperatures either.
The air was thick enough to carry a Jumbojet and support combustion of Kerosene in the engines at high rate, allthough with compressor, so the air is there! keeping -70 Celcius.
That air is intensely heated from below when it rains and storms. In fact, Cooling from that side drives the trade- winds and the tropical hurricanes, The roaring fourties and the worlds very fameous large and steady sea currents. The warm side of that engine is sunshine down on the sea and on the ground , but the stratosphere and the Tropopause is the cold side of that same TERMO-DYNAMIC Sterling or Carnot- engine that makes the worlds quite dramatic stormy weathers.
So what cools that cold reservoir, that steam- engine turbine condenser down to -60 and even -70 celcius all the time and worldwide?
There are a dozen compelling reasons for switching from fossil fuels to renewables but deniers will dismiss all of them because their money holds higher value than life. They will drown whole countries, send children to kill and die for access to oil fields, poison infants with mercury, wipe out wildlife and choke us all with particulates just so their Exxon and Consolidated Coal stock doesnt lose a few points.
Reply | Report Abuse | Link to thisWhen heat is going into the alleged melting of this much ice/snow because the surface is dirty with soot and dust, not only is the efficiency of the solar radiation vastly improved, but there is less reflected solar energy left over to heat the atmosphere. Thus a dirty-surface glacier will melt faster in the summer and the actually colder air in the Northern Hemisphere will not be able to replace the glacial loss with new snow fall because supercold atmospheres are dry and not conducive to heavy snow.
Reply | Report Abuse | Link to thisWe definitely need an honest re-appraisal of what glaciers in areas not polluted by the enormous amounts of soot now coming from China and India are doing.
One phrase about a climate model predicting something struck me as real news. Since when do precisely specified climate models predict anything successfully?
Anyhow, the thermalhaline currents are not changing.
If AGW ia wrong (an open question at this point) then outlawing Fossil fuels will kill billions (alternatives are too costly for most poor nations).
Reply | Report Abuse | Link to thisSo who is trying to kill people now? To save your god, AGW, you will sacrafice billions. Congratulations. You will outdo all other tyrants combined.
It is a bit off the topic but, can anyone here explain to me:
Reply | Report Abuse | Link to thisWHAT COOLS THE STRATOSPHERE, AND QUITE ESPECIALLY THE TROPO-PAUSE?
That is a most crucial question because, together with sunshine that heats the oceans and the ground, that remarkably cold Tropo- pause is the very THERMO-DYNAMIC DRIVING MECHANISM of the worlds winds and storms and hurricanes, and the very fameous and large sea- currents.
I have opened the books on it. The book say that Tropopause and stratosphere begins at 18 Km in the tropes, and 8 Km at the poles. Temperatures -50-60 Celcius. Which is obviously not allways true. I had the pleasure to glide in a Jumbojet from Frankfurt to Boston 14 Oct 2007, altitude 11.8 to 12 Km. And temperature outside was -67 to-70 Celcius, beat that!
Air pressure halves at each 5.5 Km. Still, that Jumbojet could glide on less than 1/4 air density and burn Kerosene at high rate, allthough with compressor. Air is obviously still there. But, what cools it?
It cannot be the poles because there, the temperatures are higher, and if they cool, what cools the poles then?
-67-70 celius is solidly below the common winter frost records at night in Siberia. Keep that also in mind.
That tropopause seems to be the cold surface or the cold reservoir or wall or the cold and cooling envelope of the earth, that cools the earth's stirling- engine or carnot- cyclic engine, or it is the condenser on the cold side of the huge steam- engine- turbines that drives the worlds weathers, the thyphoons and the hurricanes and the roaring fourties.
Huge ammounts of heat are brought up there to warm it up, the very evaporation and freezing entropy of all that water that comes down again and cools you and allmost drowns you when there is hurricane. Huge showers of ice, Tight showers of icy golf- balls smashes the tiles and the cars,.... what did cool and freeze them? They were vapour. It is an enormeous lot of heat going up vertically in the air. What is able to cool and to keep the temperatures of the stratosphere and tropopause solidly below sibirian winter records all the time and worldwide, an even with the sun right in Zenith?
Climate change is a given, so what's the big deal.
Reply | Report Abuse | Link to thisWhile geologically speaking what's happening is extremely sudden and quick, we humans have a far different and much shorter perspective.
Climate change is happening, but in human terms it's effects on where we live on the planet are only gradually making themselves apparent. Hell, The maldeves are still above water!
The real irony is we humans will eventually not really do anything effective to stop it.
Humans are never successful at solving problems set to have their impact that takes longer than the average human lifetime to set in.
Fortunately, in human terms, we will have no real issues adjusting.
Land lost to the sea will be replaced by land once too cold to live in great numbers.
And those that can't flee will suffer from the changes, but only gradually, and most alive today extremely few will die from the effects of climate change on their place of residence.
By the time climate changes have come on full force sometime in our great great grandchildren's lifetime, the vast majority of humanity will have migrated or adjusted in some way to the changes - and it will happen if we do nothing or we do something - so what's the big deal.
Still since so many feel it's imperative to stop something we cannot stop in our lifetime, efforts should be common sense, like doing our best to restore wetlands or moving cities in high risk zones to higher ground.
We certainly have a lifetime or two to accomplish those things, and it beats the financial con called carbon trading.
Climate change is a given, so what's the big deal.
Reply | Report Abuse | Link to thisWhile geologically speaking what's happening is extremely sudden and quick, we humans have a far different and much shorter perspective.
Climate change is happening, but in human terms it's effects on where we live on the planet are only gradually making themselves apparent. Hell, The maldeves are still above water!
The real irony is we humans will eventually not really do anything effective to stop it.
Humans are never successful at solving problems set to have their impact that takes longer than the average human lifetime to set in.
Fortunately, in human terms, we will have no real issues adjusting.
Land lost to the sea will be replaced by land once too cold to live in great numbers.
And those that can't flee will suffer from the changes, but only gradually, and most alive today extremely few will die from the effects of climate change on their place of residence.
By the time climate changes have come on full force sometime in our great great grandchildren's lifetime, the vast majority of humanity will have migrated or adjusted in some way to the changes - and it will happen if we do nothing or we do something - so what's the big deal.
Still since so many feel it's imperative to stop something we cannot stop in our lifetime, efforts should be common sense, like doing our best to restore wetlands or moving cities in high risk zones to higher ground.
We certainly have a lifetime or two to accomplish those things, and it beats the financial con called carbon trading.
Hob Goblin, do a little reading. There is no universal acceptance of anything. Some people think earth is 6000 years old. However the overwhelming evidence suggests human caused warming. We have the highest level of CO2 in the atmosphere in at least the last 500,000 years and a clear correlation of CO2 to temperature. Contrary to what you say we know quite a lot about the output of the sun and its contribution to warming and know the sun is not the cause of the increase in global temps.
Reply | Report Abuse | Link to thisHey Greenies; I *read* you emails. A bunch of back-stabbing-fact-denying sons-o-bitches.
Reply | Report Abuse | Link to thisAGW. Yeah, right. Go algore. Let's give Greenies $9 Trillion just because they're such a nice group of boys and girls.
Carbomontanus wrote: "It is a bit off the topic but, can anyone here explain to me: WHAT COOLS THE STRATOSPHERE, AND QUITE ESPECIALLY THE TROPO-PAUSE?...that remarkably cold Tropo- pause is the very THERMO-DYNAMIC DRIVING MECHANISM of the world's winds and storms and hurricanes, and...sea- currents...
Reply | Report Abuse | Link to thisThat tropopause seems to be the cold surface or the cold reservoir or wall or the cold and cooling envelope of the earth, that cools the earth's stirling- engine or carnot- cyclic engine, or it is the condenser on the cold side of the huge steam- engine- turbines that drives the worlds weathers, the typhoons and the hurricanes and the roaring fourties.
You're asking the question the wrong-way round, Carbomontanus. Ultimately the entire atmosphere is cooled by the surrounding vacuum of space, at 0�K. It does not matter that the sun shines brightly: any atoms incapable of absorbing radiation will assume the same temperature.
The stratosphere (above the tropopause), because it increases in temperature with elevation, is the exception to the anticipated linear decline-in-temperature-with-elevation, & that is because the ozone layer, at the top of the stratosphere, is capable of absorbing the sun's UV radiation & conducting a portion of the resulting heat downward. This conductance produces the stratosphere's inverted heat structure.
You should not be asking, therefore, 'what cools the tropopause?', as if the cold of the tropopause is an active agent in earth's climate. Rather, it is a PASSIVE result & interface between the two dynamic processes that tend toward warming it: heat convection in the troposphere below, & heat conduction from the (top of the) stratosphere above.
Without the ozone layer, the temperature structure of the atmosphere above the troposphere would be entirely different (& much simpler), with catastrophic results for much of the biosphere, including us.
I hope this answers your question.
Some parts of the oceans near the poles are getting less salty due to ice-melting. Other parts near the equator may be receiving more heat from the warmer air above. These would most likely affect the existing ocean currents and enhance the temperature change on coastal lands.
Reply | Report Abuse | Link to thisThe outcome is complex. It could become a vicious circle, making the whole issue of climate change more perplexing.
(btt1943)
I am sure that the developments in human life on the planet over the last 3 centuries, especially the enormous increase in population, have had drastic impacts on the environment, climate change being only one of those impacts. While people quibble about the details of climate change, those changes and all the others, continue to grow and threaten human life as we have come to expect to live it. Over-fishing, rain-forest destruction, garbage, chemical pollution, are some of the serious issues apart from the possible impacts of global warming. Unless, or until, human beings understand that we are merely one, relatively unimportant, part of a vast system, which has no particular interest ( being anthropomorphic!) in our survival, we will probably continue to dig our own graves. Without a fundamental change in our understanding of our situation, I doubt that we can avoid disasters ahead; I fear for my grandchildren and their children.
Reply | Report Abuse | Link to thisJoy Lumsden
Isn't this the type of interference to global hydrology the INDOEX group of scientists predicted, following their surprise 1999 discovery of an unrelenting pall of smog over the equatorial waters of the North Indian Ocean?
Reply | Report Abuse | Link to thisKnown as the Asian Brown Haze, then measuring 3-4kms thick in places and covering an area the size of USA, it prevents the sun's rays from heating the water below.
There appear to be two adverse influences of this Haze -
1. the affect it has on the Global Conveyor Belt.
2. a lack of evaporation necessary for rain cloud formation. Hence areas of India, Africa and Australia are receiving dry intstead of normal moist air leading to droughts and heatwave conditions.
It's important to note, from the largely ignored INDOEX report, the composition of the Haze stems mostly from man-made fossil burning. Domestic activities of the huge population of the region, deforestation using fire and an estimated 1/3 from coal-fired emissions of rapidly growing industry all contribute.
These emissions could readily be averted if the domestic practices of heating/cooking are changed ; fired deforestation be banned; smokeless char [coke] become mandatory for coal burners, as was used in the 1950's to defeat the infamous UK smog.
Unless action is taken and soon the situation in the region is going to worsen markedly, with the declaration by China and India of a massive expansion of industry, largely coal driven,
The climate models include a newly discovered phenomenon called greenian motion. Increased CO2 causes the atmosphere and oceans to move in ways that result in all locations on earth to become worse.
Reply | Report Abuse | Link to thisSorry fools, the earth is cooling now not warming. Just a natural cycle that has been going on for a millenium. AGW is a fraud and hoax. End of story.
Reply | Report Abuse | Link to thisGood point. With more melting the flow may increase, thus maintaining lower temperatures. Once the melting passes the peak temperatures could rise rapidly. With the increased melting there may actually be cooling for some time until the source of the cooling disappears...
Reply | Report Abuse | Link to this... just like melting ice in a beer cooler. Nobody likes warm beer!
"The basic premise appears to be that humans are causing climate change yet there is not universally accepted theory and data supporting this contention."
Reply | Report Abuse | Link to thisScience by proxy.