From the National Science Foundation: Threading the Climate Needle: The Agulhas Current System
Increased Agulhas “leakage” significant player in global climate variability
The Agulhas Current which runs along the east coast of Africa may not be as well known as its counterpart in the Atlantic, the Gulf Stream. But now researchers are taking a closer look at this current and its “leakage” from the Indian Ocean into the Atlantic Ocean–and what that may mean for climate change
In results of a study published in this week’s issue of the journal Nature, a team of scientists led by University of Miami Rosenstiel School of Marine & Atmospheric Science Oceanographer Lisa Beal, suggests that Agulhas leakage could be a significant player in global climate variability.
The Agulhas Current transports warm and salty waters from the tropical Indian Ocean to the southern tip of Africa. There most of the water loops around to remain in the Indian Ocean (the Agulhas Retroflection), while some water leaks into the fresher Atlantic Ocean via giant Agulhas rings.
Once in the Atlantic, the salty Agulhas leakage waters eventually flow into the Northern Hemisphere and act to strengthen the Atlantic overturning circulation by enhancing deep-water formation.
Atlantic overturning circulation is technically known as Atlantic meridional overturning circulation (AMOC); it carries warm shallow water into northern latitudes and returns cold deep water southward across the equator.
Recent research points to an increase in Agulhas leakage over the last few decades, caused primarily by human-induced climate change.
The finding is profound, oceanographers say, because it suggests that increased Agulhas leakage could trigger a strengthening in Atlantic overturning circulation–at a time when warming and accelerated meltwater input in the North Atlantic has been predicted to weaken it.
“This could mean that current IPCC model predictions for the next century are wrong, and there will be no cooling in the North Atlantic to partially offset the effects of global climate change over North America and Europe,” said Beal.
“Instead, increasing Agulhas leakage could stabilize the oceanic heat transport carried by the Atlantic overturning circulation.”
There are also paleoceanographic data to suggest that dramatic peaks in Agulhas leakage over the past 500,000 years may have triggered the end of glacial cycles.
These data are further evidence that the Agulhas system and its leakage play an important role in the planet’s climate, Beal and others say.
“This study shows that local changes in atmospheric and oceanic conditions in the Southern Hemisphere can affect the strength of the ocean circulation in unexpected ways,” said Eric Itsweire, director of the National Science Foundation (NSF)’s physical oceanography program, which funded the research.
“Under a warming climate,” said Itsweire, “the Agulhas Current system near the tip of South Africa could bring more warm salty water from the Indian to the Atlantic Ocean and counteract opposing effects from the Arctic Ocean.”
The study establishes the need for additional research in the region that focuses on Agulhas rings, as well as on the leakage, believes Beal.
Climate modeling experiments are critical, she said, and need to be supported by paleoceanographic data and sustained observations to firmly establish the role of the Agulhas system in a warming climate.
“Our goal now is to get more of the scientific community involved in research on the Agulhas system and its global effects,” said Beal. “The emphasis has been too long in the North Atlantic.”
The Agulhas Current Time-Series Experiment, or ACT, was launched in April 2010 to measure the variability of the Agulhas Current using a combination of current meter moorings and satellite data.
Beal, who serves as chief scientist, spent one month aboard the research vessel Knorr in the southwest Indian Ocean deploying oceanographic instruments.
The data gathered in situ, when combined with along-track satellite information, will help increase our understanding of how the Agulhas system is changing in a warming climate, Beal said.
The scientific team included Beal, Wilhelmus P.M. de Ruijter of Utrecht University in the Netherlands, Arne Biastoch of Leibniz- Institut für Meereswissenschaften (IFM-GEOMAR) in Germany, and Rainer Zahn of the Universitat Autònoma de Barcelona in Spain.
It also included members of the Scientific Committee for Oceanic Research (SCOR) Working Group 136 on the Climatic Importance of the Agulhas System, sponsored by SCOR, the International Association for the Physical Sciences of the Oceans, and the World Climate Research Program.
For information on the program, please visit the ACT website.
-NSF-
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some twisted logic.
1. criticize models for not capturing everything
2. scientist finds something not well represented in the models
3. scientist suggests more study ( to fix #1)
4. people complain that scientist does number 3.
damned if they do, damned if they don’t
that’s not exactly fair to them folks
After world temperatures appeared to peak in 1998, the number of climate scientists producing an ever increasing amount of drivel has “sky rocketed, exponentially” (their terminology not mine)
Meanwhile, back on planet earth, not much has happened to temperatures, perhaps a bit down if anything.
Is this the correlation and negative feedback that Hansen missed back in 1988?
It seems as likely as the CO2 scam
There are also paleoceanographic data to suggest that dramatic peaks in Agulhas leakage over the past 500,000 years may have triggered the end of glacial cycles.
Yet the current leakage is caused by human induced global warming.
This is a prime Homer Simpson moment. D’OH
However, the study is worthwhile because finally it is sinking in that the oceans drive temperature, not a miniscule trace gas.
Everyone should read Erl Happ
http://climatechange1.wordpress.com/2011/04/20/the-common-sense-of-climate-change/
It’s interesting how different people focus on different parts of the article. The part that struck me the most was the following:
ie. Form a hypothesis (model) and then test it with real data….
Wow! Impressive. Water mixes on a round Earth spinning with a speed of 460 m/s, about 1,070 mph while spinning the Earth is moving around the Sun, the whole Solar System is moving around the Galaxy and the Galaxy is moving through space! This is devastating stuff. Meanwhile the moon causes tides to rise and lower. We must have money to study this phenomenon. Surely this spinning ball must have winds, waves, and countless currents – MONEY! We MUST have money. This surely is a study worth millions! And this yellow thing in the sky? What is this? MONEY! We need even more money to investigate.
No researcher who had the phrase “human caused climate change (or warming) deserves fair treatment since they’ve already indicated that they themselves are biased.
“…caused primarily by human-induced climate change.” Do we have yet another re-branding, “Human-induced Climate Change” or HICC? Or, since all or the GCM’s and other IPCC ouija boards predict that the temperature only goes in one direction, UP, should we now call it HICC-UP?
steven mosher says:
April 27, 2011 at 3:49 pm
some twisted logic.
1. criticize models for not capturing everything
2. scientist finds something not well represented in the models
3. scientist suggests more study ( to fix #1)
4. people complain that scientist does number 3.
damned if they do, damned if they don’t
that’s not exactly fair to them folks
==========================================
They made their bed when they insisted on being the eyes, ears and mouths of our policy makers based upon incomplete findings. We knew they were incomplete, they knew the findings were incomplete, the whole damned world knew it was guesstimations (at best, political advocacy more likely) and much of the Western Civilization had Kyoto shoved up their posteriors anyway.
They damned themselves on their first “do” when the rest of the world was screaming “don’t”.
And Steve, they’re not fixing anything, they’re looking for more stuff to try to scare people with. While it didn’t explicitly say it, they might as well have said, “It’s worse than we thought!”
Yeah, I wouldn’t rag on these guys too much.
They need research money too, and “climate research” is where the $ is at, at first glance it seems pretty pro-forma stuff to appeal too…..in order to actually do some primary research on on less well know current that might have some real consequences.
The interesting things about a lot of the climate research is that if you strip out the chicken little verbiage some of it _is_ decent research.
The amazing thing to me is that all these little factoids are being conflated into some big climate thing, when what we are really doing is peering at the elephant through a keyhole. It’s gray and hairy and moving…. the fact that you think it’s an elephant is speculation, but with a lot more peeing over time, you MIGHT get to be able to identify what the heck it is you are looking at.
…all OF the GCM’s
Hate to take the easy road, but……….
“could mean that current IPCC model predictions for the next century are wrong”
I thought that was always a given.
Steve Mosher
Thing is Steven why do they try to tie everything in to AGW,we all know the models are wrong because you can not account for everything that happens in earths ocean/climate,why don’t these researchers just come out and say it all a part of the natural variations of the planet systemsand we donj’t understand the mechinism, instead of its happening because of AGW.It’s been happening before we stared to put Co2 in the planets atmosphere/oceans and will more likely continue to happen long after we are gone from this planet.
steven mosher says:
April 27, 2011 at 3:49 pm
that’s not exactly fair to them folks
===================================================
mosh get serious
They jumped the shark, tagged it to global warming…..
The only thing profound about associate professor Lisa Beal’s paper is that she meet the requirements, and how many times she was able to work ‘could’ and ‘suggests’ into one paper……………….
Fred2 – “but with a lot more peeing over time” – – – so bring on the beer!!!
Since the fundamental of CAGW is that additional CO2 in the atmosphere heats the atmosphere and then the oceans/land in a top-down way, this doesn’t impact the results of the IPCC theory. The heat moves around differently, but that’s it. The IPCC models were “matched” to historical records. Even though the details of the mechanisms aren’t correct, the net result won’t change.
The heating of the planet and ice melt rates are all that need to be watched. When these fall off the predictions, either the amount of forcing for CO2 is wrong or there are negative feedback mechanisms not in their models. Both invalidate CAGW principles. 60% of a 3C warming rate is no longer a carbon-tax target when the End of Mankind is what has driven the scare so far.
Let people study what they will. It’s the metrics in the next few years that will do the dirty deed.
The science is finally settled. Someone call Al Gore. I can sleep easy now knowing that the science if finally and utterly settled. Prepare for Thermageddon!!!!
Mosh, Mosh, Mosh…. you’ve been in this game long enough to understand climate talk. When a researcher uses the words such as “warming planet” they’re not just referring to a measurement of surface temperature. It’s “Human Induced Global Warming” by it’s shorthand and even that really means CO2. Unless the researcher has been branded a denialist and heretic you know that’s what they’re really saying.
Steve,
It’s not ‘damned if they do, damned if they don’t’. It’s damned if they jump to the conclusion of ‘human caused’ without the empirical evidence to back it up.
…and still there are folks out there who insist,
“The science is settled !”.
I predict that in years to come our children will laugh at this current generation of so called ‘climate scientists.’ It will become clear that the nonsense that gushes out is being fuelled by money. Governments now find themselves making decisions based on utter natural chaos and climate scientists’ need to make ends meet. It could be as simple as that.
I’m with Mosh here… these guys are out there actually gathering real data, which they freely suggest might well invalidate the all-seeing, all-knowing models.
Surely that is exactly what’s needed??
Yeah, they throw in the obligatory crumb to HICC-UP, but that’s about getting funds, and without said funds the science doesn’t get done…
“Recent research points to an increase in Agulhas leakage over the last few decades, caused primarily by human-induced climate change”
This is their seeeking-more-funding statement. However, the assumption, after all of this that it is caused by “human-induced climate change” means that I lose most of my confidence in anything they may have found. Except for the fact that they are saying that the IPCC is wrong in their predictions, their support of junk science indicates a clear lack of clear thinking on their part. They send a disturbing mixed message.
I want to see how they support the idea that climate change is “human-induced.”
Oh bloody hell! Australia is toast!
Fred2, problem is that if these guys were simply playing the game so they could get funding for honest research, they have already tainted their research; they have to produce the desired result, or no more government (read “The Peoples'”) money.