A switch in ocean circulation that helped end the Ice Age

A switch in ocean circulation that helped end the Ice Age
Credit: University of St Andrews

Changes in the circulation of the North Pacific Ocean about 15,000 years ago released large amounts of CO2 to the atmosphere, helping warm the planet and end the last Ice Age, according to research by scientists at the University of St Andrews.

The new study, published today (23 April) in Nature Geoscience, also found that the changes in circulation resulted in a reduction of the amount of in the . The findings will help scientists understand the processes controlling the exchange of CO2 and oxygen between the ocean and atmosphere.

The researchers measured the chemical composition of the shells of tiny fossil plankton, called foraminifera, which they used to reconstruct the exchange of CO2 between the North Pacific Ocean and atmosphere at the end of the last Ice Age, a time when carbon dioxide levels in the atmosphere increased. They found the North Pacific released large amounts of CO2 to the atmosphere about 15,000 years ago, a time when in the Atlantic were also changing rapidly. Findings showed that the release of CO2 by the North Pacific was caused by a change in its circulation and could explain a drop in oxygen levels in the Pacific Ocean seen at the same time, first discovered over 20 years ago. Scientists are observing a similar loss of oxygen from the ocean as the climate changes today.

Lead author, Dr. Will Gray from the School of Earth and Environmental Sciences at the University of St Andrews, formerly of University College London, said: "Last week we saw worrying new studies showing us the ocean currents in the North Atlantic are slowing down. In our study we see very rapid changes in the climate of the North Pacific that we think are linked to past changes in currents in the Atlantic. This gives us an example of the way that different parts of the climate system are connected, so that changes in circulation in one region can drive changes in CO2 and oxygen all the way over on the other side of the planet."

Dr. Gray added: "The North Pacific Ocean is very big and just below the surface the waters are brimming with CO2; because of this, we really need to understand how this region can change in the future, and looking into the past is a good way to do that."

Co-author Dr. James Rae, also from the University of St Andrews, added: "Although the CO2 rise caused by this process was dramatic in geological terms, it happened very slowly compared to modern man-made CO2 rise. Humans have driven CO2 rise in the as large as the CO2 rise that helped end the last Ice Age, but the man-made CO2 rise has happened 100 times faster. This will have a huge effect on the climate system, and one that we are only just beginning to see."


Explore further

The last ice age

More information: William R. Gray et al. Deglacial upwelling, productivity and CO2 outgassing in the North Pacific Ocean, Nature Geoscience (2018). DOI: 10.1038/s41561-018-0108-6
Journal information: Nature Geoscience

Citation: A switch in ocean circulation that helped end the Ice Age (2018, April 24) retrieved 23 September 2019 from https://phys.org/news/2018-04-ocean-circulation-ice-age.html
This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.
201 shares

Feedback to editors

User comments

Apr 24, 2018
No matter where we look, we find human carbon exhumation driving changes orders of magnitude faster than anything in the geological record. The U.S. is already getting hammered with hurricanes, pummeled by nor'easters, and slow roasted here in the southwest, except when this place outright bursts into flames. We should be leading the charge on this existential threat to our species, but instead we dither and polarize so as to not discomfit industries *which will not survive long due to the size of their own admitted reserves*.

It's nice to be first on a climate related article, before the mumblers show up.

Apr 24, 2018
How did Pacific circulation change when glacial low-stand of sea levels meant the thermo-haline 'passage' West of Indonesia was really, really shallow ??

Apr 24, 2018
Mackita has obviously neither read, nor understood, the paper linked from the article, nor the references therein. The reason, in the model, for the increase in CO2 production, is linked to deglaciation and a change in wind stress under glacial boundary conditions. In other words, deglacialtion adds landborne nutrients to the oceans. These nutrients are disturbed from deep levels by the wind stress. Hence more CO2.
For the hard of thinking, we no longer have enormous glaciers in the northern hemisphere to feed this loop. It is estimated, from ice cores, that the CO2 levels rose from 189 ppm to 265 ppm between 18.1 and 10.5 ky BP*. That happened in stages. So, 76 ppm over 7600 years. All due to forcing from end-glacial conditions and feedback loops.
In contrast, pre-industrial revolution levels have gone from ~280 ppm to ~400 ppm, in < 250 yrs. It really isn't rocket science.
*http://citeseerx....#page=27


Apr 24, 2018
Yeah, we've screwed ourselves. Can't blame the termites or dolphins. Human greed and selfish gluttony have interrupted normal cycles of climate change.

Pouring gasoline onto the flames to prove our dominance is of paramount importance.

Apr 24, 2018
@zeph
Because the global warming is actually what releases carbon dioxide into atmosphere, not humans. These imbeciles just accelerate this process in a futile effort to
if only there was a way to differentiate between natural and man-made emissions - that would tell if the releases of CO2 are due to humans

oh wait! there is!

well, that would make your entire post a bunch of idiotic rhetoric based upon denialist propaganda posted to incite or inflame because it lacks any scientific validity... just like your aether, overunity and CF claims

imagine that, you're lying because you don't comprehend the basics of science and it's methodology


Apr 24, 2018
Which reservoir of nutrients do you expect beneath molten glaciers?


If glaciers were molten, they wouldn't be glaciers. They'd be water.

Apr 24, 2018
IMO the rise of CO2 was in release of methane deposits from.....


Who cares about your opinion? You obviously don't understand what you're talking about, so it's irrelevant.

Apr 24, 2018
^^^^^^Not interested. Get it peer-reviewed and published, like real scientists have to, and then I might read it.

Apr 24, 2018
I think I know quite a lot about it (https://www.reddi...h_posts) - maybe more than I would even want to know.


I'm seriously considering creating a sockpuppet so I can really vent my spleen on some of the asinine posts I read here.

Seriously reddit as a source!

Apr 24, 2018
The humans tend to screw everything, including the megalomanic perception of their role in natural cycles. For me it's just problematic, that they refuse to test the mechanisms, which have lead to end of ice age period. The scientists already know about it - but their ignorance apparently brings more jobs for them.
you're lying because you don't comprehend the basics of science and it's methodology
I think I know quite a lot about it (https://www.reddi...h_posts) - maybe more than I would even want to know.

Your links 1 and 3 appear to be the same link...
From Steve
I'm seriously considering creating a sockpuppet so I can really vent my spleen on some of the asinine posts I read here.

Seriously reddit as a source!


Notice they are all from Zeph at Reddit, as well...

Apr 24, 2018
Get it peer-reviewed and published, like real scientists have to
I presume, every intelligent person understands, that reddit is just an passive agreggator of links from another sources. I'm using it as a online repository of my sources - nothing less, nothing more. Most of links presented there indeed originate from published peer-reviewed sources.
Your links 1 and 3 appear to be the same link
This is possible, but many of my topics are actually a long serials of links. Links, links, links - dozens, thousands of links (https://www.reddi...tone/)..

Yeah, yeah... We can see that. All from you...

Apr 24, 2018
@zeph
you would see they're actually supported by pile of facts
if your pile of facts is a reddit link that is to your aether site, then you're far more delusional than most think

you can't have it both ways: you either adhere to the scientific method or you don't
there is no middle ground in science
that reddit is just an passive agreggator of links from another sources. I'm using it as a online repository of my sources
what "every intelligent person understands" is that source material is important

so when you choose a source that is known to be malicious and pseudoscience, it stands to reason that each and every individual point of information must be scrutinized for it's validity simply because you chose to use a known malicious pseudoscience link

this is the main reason no one takes you seriously
yet another reason being your choice to defend a debunked belief and your choice to continue to spread stupidity with numerous sock puppets when proven false

Apr 24, 2018
@Whydening Gyre

Notice they are all from Zeph at Reddit, as well...

We should check all his reddit posts to see if he ever uses physorg to evidence his comprehension of "the basics of science and it's methodology". If he does he runs the risk of suffering the same fate as the Oozlum bird.

https://malagabay...um-bird/

Apr 24, 2018
^^^^^^Christ. Word salad, or what? Wanker! Actually do some science, you jerk. Never going to happen is it?

Apr 24, 2018
But the dark matter theory of climatic changes......


Fails to exist! Idiot.! Jeez, what a moron.How many fu**ing times?

Apr 24, 2018
Uchkk. Word sandwich. Insert word salad here. It really isn't rocket science denier goonies. 400+ppm levels of CO2 will last a lot longer than you will and your buddy DT. CO2 does not go away quickly and it effects a hell of a lot. Ahhh thats the meat isn't it. Mayo, and how is that for a word sandwich. Uckkk.

What you expected a panini?

Apr 25, 2018
Does this mean co2 caused the Quaternary Glaciations?

Whatever Stone Age man was burning? It's not a shadow of what we Stone Age descendants are burning today!
Are we to assume from this article stone age man lived through this ice age that began 110,000years ago and ended 11,700 years ago lasing around 98,300 years and what were the few thousand stone age people doing burning all that charcoal that plunged their lives into utter misery for a 100,000years, because whatever they were burning? It was not even a shadow of what we Stone Age descendants are burning today. Does this mean we're heading for another 100,000years of freezing icy misery?

And just like the wind changes in Mary Poppins, its time for the ice age to recede

Apr 27, 2018
Correlation does not mean causation. Seas always outgas CO2, when they warm during an interglacial. And ice-core evidence demonstrates that warming took place before atmospheric CO2 increases.

In reality, ice ages are modulated by dust and albedo. It is the deposition of dust from the Gobi region, just before every interglacial, that lowers the albedo of the northern ice sheets and allows insolation absorption and melting. In addition, the regulating mechanism for Gobi dust is provided by CO2. When CO2 reaches a nadir during the glacial maximum, high elevation plant life on the Gobi plateau is asphyxiated, forming new CO2 deserts, which create dust. So CO2 causes global warming through the agency of eliminating high altitude plant life.

This theory explains every facet of ice age modulation.

'Modulation of ice ages via precession and dust-albedo feedbacks'.
Doi: 10.1016/j.gsf.2016.04.004
http://www.scienc...16300305 .

Apr 27, 2018
Does this mean co2 caused the Quaternary Glaciations?

Whatever Stone Age man was burning? It's not a shadow of what we Stone Age descendants are burning today!
Are we to assume from this article stone age man lived through this ice age that began 110,000years ago and ended 11,700 years ago lasing around 98,300 years and what were the few thousand stone age people doing burning all that charcoal that plunged their lives into utter misery for a 100,000years, because whatever they were burning? It was not even a shadow of what we Stone Age descendants are burning today. Does this mean we're heading for another 100,000years of freezing icy misery?

And just like the wind changes in Mary Poppins, its time for the ice age to recede

No! It means keep burning fossil fuels to fore stall the next ice age

Apr 28, 2018
The implication ocean currents increased atmospheric co2, which ended the ice age. Then the co2 was already high from the previous ice age indicating a reversal of ocean currents absorbing surplus co2 for 100,000 years. A 100,000 years on to today, are the ocean currents reversing yet again for the cycle to continue as we plunge yet again into these eternal ice ages.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more