Antarctic sea temperatures cooled in Holocene but now rising: study

Feb 10, 2011 by Lin Edwards report
ocean

(PhysOrg.com) -- A new study of an ocean sediment core taken from deep water off the coast of the western Antarctic Peninsula is beginning to fill in some of the gaps in our knowledge of climate variability in the region.

The 43-meter-long marine was analyzed by Dr Amelia Shevenell, lecturer in Geography and at University College London, and her colleagues. Dr Shevenell said good records of near the have not been available up to now, but the present research is starting to fill in the gaps.

The biological material in the sediments within the core gives a continuous profile of sea surface temperatures during the Holocene period, which extends back some 12,000 years from the present. This period has been characterized by a warm and relatively stable climate.

The core indicates that surface at the margins of the peninsula cooled by 3-4 °C over the past 12,000 years, which follows the decline of spring incoming solar radiation (insolation) in the area during that period due to shifts in the Earth’s orbit.

The study also found the cooling is now being offset by the current climate change, and sea temperatures have been rising at around the same rate as land temperatures in the Antarctic, estimated at around 3-4 °C per century.

Similarities between sea surface temperatures derived from the core, data on the Southern Hemisphere westerly wind reconstructions, and the El Niño southern oscillation, suggest the connections between the tropical Pacific Ocean and the western have strengthened within the last 2,000 years of the Holocene.

The authors of the paper, published in the journal Nature, say that during the Holocene period temperatures in the Southern Ocean at the margins of the western Antarctic Peninsula have been tied to changes in the position of the westerly winds.

Current climate models predict more frequent and stronger El Niño - La Niña cycles, which could weaken the ice shelves along the peninsula and make them more likely to disintegrate. A melting of the ice shelves could raise sea levels, but Dr Shevenell said it is not possible to predict how high temperatures would have to be to trigger widespread collapses of the ice shelves.

Explore further: The relationship between the movement of wind turbines and the generation of lightning

More information: Holocene Southern Ocean surface temperature variability west of the Antarctic Peninsula, by A. E. Shevenell et al., Nature 470, 250–254 (10 February 2011) doi:10.1038/nature09751

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User comments : 20

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Shootist
3 / 5 (4) Feb 10, 2011
Uh, this IS the Holocene.
Uri
4 / 5 (5) Feb 10, 2011
Current climate models predict more frequent and stronger El Niño - La Niña cycles, which could weaken the ice shelves along the peninsula and make them more likely to disintegrate.


Things like this are what upset me in reporting on science: According to http://www.pmel.n...faq.html (which appears to be out of date btw), evidently the official NOAA stance (question 18)is:
"For example, some scientists have speculated that a warmer atmosphere is likely to produce stronger or more frequent El Niños, based on trends observed over the past 25 years. However, some computer models indicate El Niños may actually be weaker in a warmer climate. "

How does one reconcile the statements? If thats a true statement then I'm fine with it, but the paper itself says: "If ENSO increases in strength and frequency, as predicted for future climatic warming," without providing a reference either.....

If someone has a source, please enlighten me.
NotParker
2 / 5 (12) Feb 10, 2011
Antarctica is not warming. Previous claims of Antarctic warming were incorrect because Eric Steig made some bad statistical choices.

ht_DELETE_tp://bishophill.squarespace.com/blog/2011/2/8/steigs-method-massacred.html
Scientifica
2 / 5 (12) Feb 10, 2011
More global warming hoaxsters...they just will never stop!
Doom1974
3.4 / 5 (10) Feb 10, 2011
Enough with the "AGW is a conspiracy" theories. If it is such a conspiracy with hundreds or thousands of scientists around the world, I am really baffled that nobody can expose them as such, who is behind the conspiracy, who is pulling the lines?

Look at the data, look at the trends. Even if humans had nothing to do with it, it will change your kids' lives. Let's say we don't spend a penny to reduce CO2 emissions, and 50 years from now we find that we were all wrong and we could have prevented that or slowed it down. Are you willing to condemn your descendants to such a future?
Burnerjack
2.7 / 5 (7) Feb 10, 2011
So, does this mean that the Earth was WARMER than the temperature of modern times? Hmmm....
Doom1974
3.3 / 5 (7) Feb 10, 2011
Nobody says that the earth was never warmer than the temperature of modern times idjit. That is not the point of the article. The point is that Antartica has been cooling down for the last 12,000 years due changes to the orbit, but has been heating up recently at a large rate, that has offset said cooling.
Burnerjack
4.5 / 5 (4) Feb 10, 2011
Now, before some of you start foaming at the mouth while typing a fervent response, let me add that its NEVER a good idea to contaminate one's environment.
As far as "saving the earth". The Earth will survive us even in the event of a nuclear holocaust, We, on the other hand, may indeed perish from the face of the Earth.
Uri
3 / 5 (6) Feb 10, 2011
If someone has a source, please enlighten me.


Its nice when you get rated down for commenting on that you can't find a source to confirm the validity of a claim. Since the impact of the article is predicated upon climate change causing stronger ENSO events, it would seem that you would want to establish that climate change will cause such events. When people stop asking questions and believe everything they read how is that any different than religion? Conspiracy theorist? Hardly I just like my projections of gloom and doom to have some veracity.
jjoensuu
not rated yet Feb 10, 2011
"over the past 12,000 years, which follows the decline of spring incoming solar radiation (insolation) in the area during that period due to shifts in the Earth’s orbit"


So earths orbit shifted AFTER or DURING Holocene? So during the last 12K years?

Might anyone know where I can find more about this?
Howhot
1 / 5 (4) Feb 10, 2011
The core indicates that surface ocean temperatures at the margins of the peninsula cooled by 3-4 °C over the past 12,000 years, which follows the decline of spring incoming solar radiation (insolation) in the area during that period due to shifts in the Earth’s orbit.
The study also found the cooling is now being offset by the current climate change, and sea temperatures have been rising at around the same rate as land temperatures in the Antarctic, estimated at around 3-4 °C per century.


There is the meat slime bag deniers. Have at it.
PinkElephant
not rated yet Feb 10, 2011
@Uri,

Here's the skinny:

en.wikipedia.org/wiki/El_Niño-Southern_Oscillation#ENSO_and_global_warming

@jjoensuu,

Do a web search on "Milankovitch cycles" (you might start with the Wikipedia article...) Earth's orbit and inclination are always in the process of slowly oscillating.
PinkElephant
5 / 5 (1) Feb 10, 2011
Ok, that didn't quite work... one more time:

en.wikipedia.org/wiki/El_Nino-Southern_Oscillation#ENSO_and_global_warming
Howhot
2.3 / 5 (3) Feb 10, 2011

The core indicates that surface ocean temperatures at the margins of the peninsula cooled by 3-4 °C over the past 12,000 years, which follows the decline of spring incoming solar radiation (insolation) in the area during that period due to shifts in the Earth’s orbit.
The study also found the cooling is now being offset by the current climate change, and sea temperatures have been rising at around the same rate as land temperatures in the Antarctic, estimated at around 3-4 °C per century.


There is the meat deniers. So what kind of screwy logic will you come up with?
Howhot
1 / 5 (1) Feb 10, 2011
Opps. Sorry about that. I kept getting an error posting and it would say something about Shootist being corrupt, try again in 3 minutes. I guess it was a glitch.
GSwift7
1 / 5 (1) Feb 11, 2011
@ Uri:

If someone has a source, please enlighten me


I would avoid the wiki pages for just about anything related to climate study. They are notoriously bad, as people with political and ideological agendas manipulate the content. Try to google the following and click the top link for NOAA's Geophysical Fluid Dynamics Laboratory resource page about the ENSO cycle:

gfdl enso page

The GFDL are the top ENSO experts in the world as far as I know. Also note the links at the very bottom of the page that will give you info on the other major ocean cycles. The PDO is of special interest in relation to the above article.

In summary, Bill Kessler from NOAA has a FAQ page. He says that climate change is sure to effect ENSO in some way, since everything is connected, but they have no idea yet how a given climate change will effect ENSO. Floods in the Andese were stonger in the last interglacial, so maybe ENSO will get stronger with a warmer climate, but who knows.
GSwift7
3 / 5 (2) Feb 11, 2011
I love this statement from Bill's FAQ page:

So if you ask me "Why are there trade winds?", I will say "That's simple, there are trade winds because the water is cold in the east and warm in the west". But if you ask me "Why is the water cold in the east and warm in the west?", I'll say "That's simple too, it's because there are trade winds". The ocean and the atmosphere are inextricably coupled together

lol
MikeyK
1 / 5 (1) Feb 13, 2011
Why the lol...the statement is true! What can affect the ENSO is the temperature of the upwelling water in the east, this affects the trade winds which affects sea surface temperature which affects........
Look at the big picture, denialists don't realise the complexity of the climate and cherrypick one little detail for their myth/religion/conspiracy theory I I notice youprobably fall into the latter category with your mythological Wikipedia view)...oooohhh..the nasty wikipedia people are trying to brainwash us with their "Politals and ideological agendas"...ohhh..scary...Pathetic
kaasinees
not rated yet Feb 13, 2011
Global warming deniers really need to read about the Gaia hypothesis.
GSwift7
1 / 5 (1) Feb 14, 2011
Why the lol...the statement is true!


Because sometimes the truth is funny, and I love the way he states it. I think the guy has a tallent for writing, and I think his comment was supposed to be a funny or at least entertaining way to stating the truth. I lol'ed in appreciation of his wit.

Global warming deniers really need to read about the Gaia hypothesis


No, deniers need to read about science, as do most other people. People like you, with your Gaia nonsense, muddy the waters and make Greens sound like a lunatic fringe that does not accurately describe the majority of Greens. Extremists discredit the side they support and probably do more harm than good. Rush Limbaugh and Al Gore are good examples of that.

The deniers are as bad as the alarmists in that both groups claim they 'know' more than science claims to know. The official views of all major expert organizations are clear on that. Look at NOAA, WMO, AMS, NAS, or even IPCC(but the UN is a political org)

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