From Eurekalert: Earth’s climate change 20,000 years ago reversed the circulation of the Atlantic Ocean
Global warming today could have similar effects on ocean currents and could accelerate climate change
The Atlantic Ocean circulation (termed meridional overturning circulation, MOC) is an important component of the climate system. Warm currents, such as the Gulf Stream, transport energy from the tropics to the subpolar North Atlantic and influence regional weather and climate patterns. Once they arrive in the North the currents cool, their waters sink and with them they transfer carbon from the atmosphere to the abyss. These processes are important for climate but the way the Atlantic MOC responds to climate change is not well known yet.
An international team of investigators under the leadership of two researchers from the UAB now demonstrates the response of the Atlantic MOC to climate change in the past. The new research results will be published on 4 November 2010 in the international front-line journal NATURE. The research project was led by Rainer Zahn (ICREA researcher) and Pere Masque, both of the UAB at the Institut de Ciència i Tecnologia Ambientals (ICTA) and Department of Physics. With collaborators at the universities of Seville, Oxford and Cardiff (UK) they investigated the distribution of isotopes in the Atlantic Ocean that are generated from the natural decay of uranium in seawater and are distributed with the flow of deep waters across the Atlantic basin. The young investigator Cesar Negre studied the natural abundance of these isotopes in the seafloor sediments 2.5 km deep in the South Atlantic and achieved a PhD degree in the Environmental Science and Technology doctoral programme at ICTA.
The study shows that the ocean circulation was very different in the past and that there was a period when the flow of deep waters in the Atlantic was reversed. This happened when the climate of the North Atlantic region was substantially colder and deep convection was weakened. At that time the balance of seawater density between the North and South Atlantic was shifted in such a way that deep water convection was stronger in the South Polar Ocean. Recent computer models simulate a reversal of the deep Atlantic circulation under such conditions while it is only now with the new data generated by UAB scientists and their colleagues from Seville and the UK that the details of the circulation reversal become apparent. This situation occurred during the ice age 20,000 years ago.
Although this was far back in time the results are relevant for our climate today and in the near future. The new study shows that the Atlantic MOC in the past was very sensitive to changes in the salt balance of Atlantic Ocean currents. Similar changes in seawater salt concentration are expected to occur in the North Atlantic in the course of climate warming over the next 100 years. Therefore the data to be published in Nature offer the climate modelling community the opportunity to calibrate their models and improve their capacity to predict reliably future ocean and climate changes.
The research has been funded by the Spanish Ministry for Science and Innovation (MICINN).
======================================
This is just the usual press release with no link to the paper and no real scientific details to go with it, allowing compliant media minds to reprint it without questioning it. I’ll be interested to find out how they determined this reversal. If anybody locates a copy of the paper, please leave a note in comments.
I also think this headline could be true:
Atlantic Ocean ocean current reversal 20,000 years ago changed the Earth’s climate.
– Anthony
Discover more from Watts Up With That?
Subscribe to get the latest posts sent to your email.
I also think this headline could be true:
Atlantic Ocean ocean current reversal 20,000 years ago changed the Earth’s climate.
But that headline would admit that what the ocean’s do have an effect on the climate and they can’t go around saying that!
This is a very interesting piece of information. The Greenland ice cores are full of rapid and significant changes in temperature that correspond to the meltwater pulses that happened during the warming phase from glacial to interglacial.
The same signal shows up throughout the entire NGRIP record. Such reversals or at least circulation shutdowns might happen more frequently than we think. I will have to follow up on this one.
Theinconvenientskeptic.com
Several monthes ago I watched a National Geographic on the Sahara Desert showing fossils of crocs, clams, etc at various locations. It was shown that every 20,000 years the Sahara goes through a complete reversal from desert to a land of lakes and running rivers. It has done so several times and was last green 10000 or so years ago. They used layered sediment of dust off the coast of Africa to separate out desert from green eras. No mention of global warming or reversal of Atlantic currents.
” Recent computer models simulate a reversal of the deep Atlantic circulation under such conditions while it is only now with the new data generated by UAB scientists and their colleagues from Seville and the UK that the details of the circulation reversal become apparent.”
If it happened in a computer, it must be true!
There is little doubt that the Global Ocean Conveyor was different at different times in geological history. Will be interesting to see the actual data (not simulations).
Sounds dodgy to me- did they mean that before 20k YBP the current flowed in the opposite direction!?
I guess they never saw this report from Nasa then:
http://www.jpl.nasa.gov/news/news.cfm?release=2010-101
Perhaps this is related? (Seen in Erosion Control Magazine yesterday)
link: http://www.erosioncontrol.com/the-latest/ieca-university-partners.aspx
Based more on melting glaciers, but similar idea for Atlantic flow.
quote: These Megafloods entered the Gulf, rapidly raising the water level and forcing the overflow out through the many smaller Florida/Cuba Straits. This Glacial overflow then spread across the lower lying area known as the Bahama Mega-Bank. 12,000yrs. ago, (with sea levels at least 300 ft. lower than today) the Bahama Mega-Bank was an exposed land mass larger than present day Florida.
The timeframe fits the known facts.
Here is a useful page about deglaciation and the potential causes:
http://web.me.com/uriarte/Earths_Climate/10._Deglaciation.html
Talking about the tail that wags the dog…
Doug,
I am also skeptical about models as what you put in determines what you get out. In this case it is clear that meltwater pulses change things in Greenland. The signiture of that shows up frequently. This matches the observations.
It also helps show that orbital changes drive the climate. It is win for skeptics even if they don’t think so.
Here is the reference: Nature 468, 84-88 (4 November 2010)
Nature paywall:
Reversed flow of Atlantic deep water during the Last Glacial Maximum
Has abstract. Snippet:
And other similar things where the assistance of anna v, Pamela Gray, E.M. Smith and the like is appreciated for translation and digestion.
Journal reference was found in the Science Daily post of the press release.
So, we’ve got basic data points collection, and the employment of extrapolations of same, to feed a computer model, from which an ‘interesting’ result is found.
Ok. Congrats on the PhD thesis.
A nice tidbit for the crowd that doesn’t handle the concept of change (in the midst of a constantly active and cyclic system) to begin squalling that we’re all going to die horrid deaths no later than next Wednesday or Thursday if we don’t enact Plan Z immediately, or am I reading too much into it?
Article:
http://www.nature.com/nature/journal/v468/n7320/full/nature09508.html
And to think all this happened in the last glacial ice age. Conditions far different from current.
Just jumps out at you — “might it happen during every glaciation event”…. Why not?
And then why would you think the warm cycle would produce the same result. Not likely ehhh.
It’s worse than we thought.
Man’s excessive use of fossil fuels (Al Gore’s use excepted) must have CAUSED the reversal 20,000 years ago. After all, don’t the ice core studies demonstrate CO2 causing an increase of global temperature 500 to 800 years BEFORE natural increases in the level of CO2. Imagine how much more powerful anthropomorphic increases in CO2 are – perhaps orders of magnitude more powerful! What? You say an effect can’t happen before it’s cause? You are clearly a denier.
According to post modern science, cause and effect is an old fashion idea held by flat earthers and other such troglodytes. All you need to do is run a computer simulation and you create the past, present, and future without regard to anything outside of the computer. Next, you can assert “the science is settled” and get to call anyone who does not agree a “denier” or worse. Finally, you get to tax and regulate the deniers into extinction and get to feel good because you are saving the planet.
Something happened not 20,000 years ago but 10,000 thousand of years ago: Tradition say there was a big continent there…and, of course, that changed it all!.
Then, anyone of us here at WUWT can assure it, it happened that, on that ill fated continent, a group of people who called themselves the GREENS of the GAIA FOLLOWERS, or those who congregated in a then well known society, formed in Rome, called “The Club of Rome” where its members held the idea that the majority of mankind should be expeditiously sent to beyond the frontiers of the river of the death, so as they, the “chosen ones”, God’s favorites, could reestablish the Garden of Eden and live for ever, without those nasty and dirty working loving people .
Thus they managed to invent a new way to extract the energy from the Sun, however, as they all were sons and daughters of Mommy and Daddy, they ignored there were Laws in Nature which could not be interfered as it would risk the existent itself of the Planet or the portion of it where these laws would be violated. This new portentous and big, really gigantic fashioned “gadget”, was a big building with the shape of a pyramid, having on its most highest extreme a gem “crystal”, of a beautiful reddish color, then known as Ruby, which transmuted the sun’s rays into useful power, destined to power with inexhaustible energy their “Garden of Eden”. But….what really happened afterwards we all know it.
The problem is that in recent times, it seems that several of the then members of those secret societies, have reincarnated and are equally and stubbornly pursued to achieve their unforgotten and most stupid and contrary to universal laws, foolishness.
Another model. Models are great at expressing an hypothesis, but do not prove it.
How about some real data that can support or disprove the hypothesis instead?
20000 years ago the last glaciation was still going strong, so the climate was very different and less stable: Climate during a glaciation is unstable climate. Climate during an interglacial is stable climate. Still these scare stories – that AGW may cause similar “disruptions” – pop up again and again.
“This is just the usual press release with no link to the paper and no real scientific details to go with it, allowing compliant media minds to reprint it without questioning it. I’ll be interested to find out how they determined this reversal. If anybody locates a copy of the paper, please leave a note in comments.”
Go to the nearest university library and look it up.
“The study shows that the ocean circulation was very different in the past and that there was a period when the flow of deep waters in the Atlantic was reversed. This happened when the climate of the North Atlantic region was substantially colder…”
So if the (currently warming) north pole gets colder again we get global warming, while the warming pole proves… global warming! I love theories that can never be falsified.
Mark
Thanks for article. Interesting that MOC appears to have increased in speed from ’93 to ’09. Did the speed increase because the Earth warmed, or the opposite? Just like temp vs. CO2 concentrations, cause and effect can be hard to determine.
Bill
Wind Rider says:
November 4, 2010 at 8:12 am
A story that Discovery, History,etc. and all the pathological and thanatophilic media will air ASAP for sure !
Is it just me, or does
“The young investigator Cesar Negre studied the natural abundance of these isotopes in the seafloor sediments 2.5 km deep in the South Atlantic and achieved a PhD degree in the Environmental Science and Technology doctoral programme at ICTA.”
sound familiar? Wasn’t Mann a “young investigator” whose discovery of the hockey stick was in the course of getting his PhD?
A more detailed description of the paper seems to be here.
http://news.yahoo.com/s/livescience/20101103/sc_livescience/atlanticoceanswatersreverseddirectionstudyfinds
“To reach these conclusions, scientists investigated a pillar of sediment roughly 128 feet (39 meters) long, extracted from the seafloor by use of a ship off the coast of the tip of Africa under about 8,000 feet (2,440 m) of water.”
I’m no scientist, so maybe the scientists here can explain: if this is an accurate description, can you really determine something on this scale from “a” (presumably single) pillar (apparently the ocean equivalenty of an ice core?)?
Bill Yarber says:
November 4, 2010 at 9:05 am
The “speed of the earth” what you call it is the Length of the Day=LOD, and its changes are absolutely cyclical and related to gravity/electromagnetic fields, so linked to sun’s activity.
See pdf #8th page 50, where you, comfortably siited, will see a scientific temperatues’ forecast to the year 2100, made of course by a real scientist.
Professor Leonid B. Klyashtorin, of the Federal Institute for Fisheries and Oceanography, Moscow, Russian Federation (e-mail: Klyashtorin@mtu-net.ru)
ftp://ftp.fao.org/docrep/fao/005/y2787e/
Document Archive: y2787e08.pdf pp.50
which shows a low at the year 2020, the same as WUWT regular, M.Vukcevic’s extrapolation of Sun’s polar fields:
http://www.vukcevic.talktalk.net/PF.gif