Explosion in Antarctic sea ice levels may cause another ice age

Posted: October 30, 2019 by oldbrew in Cycles, Ice ages, Ocean dynamics, research, sea ice, Uncertainty
Tags: , , ,

Ross Ice Shelf, Antarctica

Is there an element of circular reasoning here? Carbon dioxide levels have historically followed temperature changes, bringing any supposed causation into question.

Upside-down “rivers” of warm ocean water may be one of the causes of Antarctica’s ice shelves breaking up, leading to a rise in sea levels.

But a new study suggests an increase in sea ice may lead to a much more devastating change in the Earth’s climate — another ice age, reports Fox News.

Using computer simulations, the research suggests that an increase in sea ice could significantly alter the circulation of the ocean, ultimately leading to a reverse greenhouse effect as carbon dioxide levels in the ocean increase and levels in the air decrease.

“One key question in the field is still what caused the Earth to periodically cycle in and out of ice ages,” University of Chicago professor and the study’s co-author, Malte Jansen, said in a statement. “We are pretty confident that the carbon balance between the atmosphere and ocean must have changed, but we don’t quite know how or why.”

The last major ice age ended at the end of the Pleistocene era, about 2.5 million years ago, as glaciers have periodically grown and then gotten smaller.

Researchers believe that changes to the Earth’s orbit may be partly responsible for some of the Earth’s cooling, but additional factors have likely played a part, Jensen added.

“The most plausible explanation is that there was some change in how carbon was divided between the atmosphere and the ocean,” Jansen continued. “There’s no shortage of ideas about how this happens, but it’s not quite clear how they all fit together.”

Researchers also believe a mini-ice age may have occurred roughly 12,800 years ago. It likely stems from an asteroid impact that “rocked the Northern Hemisphere” and led to the Younger Dryas climate event.

Jansen pointed out that the Southern Ocean around Antarctica “plays a key role in ocean circulation” due to the deep waters in the region, leading it to have “outsize[d] consequences.”

“What this suggests is that it’s a feedback loop,” said the study’s lead author, Alice Marzocchi. “As the temperature drops, less carbon is released into the atmosphere, which triggers more cooling.”

Full report here.
– – –
Study: Global cooling linked to increased glacial carbon storage via changes in Antarctic sea ice – Nature Geoscience.

Palaeo-oceanographic reconstructions indicate that the distribution of global ocean water masses has undergone major glacial– interglacial rearrangements over the past ~2.5 million years. Given that the ocean is the largest carbon reservoir, such circulation changes were probably key in driving the variations in atmospheric CO2 concentrations observed in the ice-core record. However, we still lack a mechanistic understanding of the ocean’s role in regulating CO2 on these timescales. Here, we show that glacial ocean–sea ice numerical simulations with a single-basin general circulation model, forced solely by atmospheric cooling, can predict ocean circulation patterns associated with increased atmospheric carbon sequestration in the deep ocean. Under such conditions, Antarctic bottom water becomes more isolated from the sea surface as a result of two connected factors: reduced air–sea gas exchange under sea ice around Antarctica and weaker mixing with North Atlantic Deep Water due to a shallower interface between southern- and northern-sourced water masses. These physical changes alone are sufficient to explain ~40 ppm atmospheric CO2 drawdown—about half of the glacial–interglacial variation. Our results highlight that atmospheric cooling could have directly caused the reorganization of deep ocean water masses and, thus, glacial CO2 drawdown. This provides an important step towards a consistent picture of glacial climates.

  1. cognog2 says:

    There seems to be a lot of navel gazing going on here through a myopic CO2 microscope.

  2. hunterson7 says:

    But but but the science is settled!

  3. hunterson7 says:

    Hmmmm….reading more, this paper is pushing a very improbable idea:
    Atmospheric temps can impact deep ocean circulation. All the evidence points to the opposite. We know that changes in ocean circulation in do change atmospheric temps and the resulting weather. How do they reconcile that?

  4. pochas94 says:

    “Atmospheric temps can impact deep ocean circulation”

    Yes they can. As can tidal effects, the same forces that affect solar activity. Anything that promotes vertical mixing of the oceans will be reflected in cooling. My favorite candidate as a climate impactor is UV intensity as it affects weather, but the dynamics of ocean mixing may be just as important.

  5. tom0mason says:

    As CO2 fails to show any warming of the atmosphere it’s about time all these idiot savants moved on and looked at all the other components that make this planet (and it’s climate) tick.
    We know the sun plays a major role,
    see http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/imgheat/temsol2.gif
    so why not make a thorough investigation of ALL variations in electromagnetic radiation spectrum, particle variations, gravitational, electric and magnetic field effect from the sun to this planet?
    What long term variations in averaged global atmospheric pressure has happened?
    What long term variations in averaged global atmospheric humidity?
    The blue end of the solar spectrum can penetrate to 100m or more of the oceans, what effects does that have?
    And what ever happened to the study of cloud formation, evolution and dissipation? It just seems to have petered out in 2009 (see https://isccp.giss.nasa.gov/products/onlineData.html ).

    The use of one trick pony of CO2 is just flogging a dead horse, it’s time to move on.

  6. oldbrew says:

    Drake Passage

    The sea ice cover extending northward from Antarctica varies seasonally. In the late summer (February) the passage is ice-free. In September the maximum ice cover occurs; 25 percent to full cover extends to 60° S, with occasional ice floes reaching Cape Horn. [bold added]

    – – –
    Fun diversion – How long until Antarctic ice touches South America?
    Anthony Watts / September 23, 2014

    = = =
    Wikipedia says:
    The passage is known to have been closed until around 41 million years ago[2] according to a chemical study of fish teeth found in oceanic sedimentary rock. Before the passage opened, the Atlantic and Pacific Oceans were entirely separate, with Antarctica being much warmer and having no ice cap. The joining of the two great oceans started the Antarctic Circumpolar Current and cooled the continent significantly.


  7. ivan says:

    tom, I doubt what you are suggesting will ever happen because it is just too hard for the acolytes of the UN Church of Climatology to understand. That sort of research required real scientists but they don’t get the money to do the work.

  8. JB says:

    Don’t get your science indoctrination at the University of Chicago…. Who wants to be graded by those who say “we don’t quite know how or why”?

  9. oldbrew says:

    Daily Mail version: ‘a reverse greenhouse effect’ 🙄

    Earth is facing another ICE AGE: Scientists claim an increase in sea ice could block the release of carbon dioxide from the ocean and cause a global COOLING

    Computer simulations show that an increase in sea ice could spark an ice age
    Acts as a lid on the ocean, blocking it from releasing carbon dioxide
    This would create a reverse greenhouse effect and cool the earth

    – – –
    What happened to the carbon cycle? Cooling oceans are supposed to absorb CO2 not emit it.

  10. pochas94 says:

    “What happened to the carbon cycle? ”

    Probably has nothing to do with it.

  11. oldbrew says:

    Why would increasing sea ice be ‘blocking it from releasing carbon dioxide’ when it wouldn’t be releasing it anyway if the oceans were cooling?

    Conversely, if the oceans around Antarctica weren’t cooling the sea ice wouldn’t be increasing. So when would the supposed problem arise?

  12. craigm350 says:

    Reblogged this on WeatherAction News and commented:
    So let me get this right, CO2 covers all climate eventualities in the same way that unicorns are magic and can do pretty much anything…except save the planet because only the drastic action of curtailing your cash and liberty can do that. 😉

  13. phil salmon says:

    There is an error in this paragraph – the Pleistocene ended 12,800 years ago, not 2.5 million years ago. That was when it began.

    The last major ice age ended at the end of the Pleistocene era, about 2.5 million years ago,

    A curious story no doubt lies behind this little snippet at the end of the linked article:

    Correction: A previous version of the story said the study had implications for future events. It was only about past events.

    Thought police having their cages rattled 🙂

  14. phil salmon says:

    Are people finally noticing the persistent cold sea temperature anomalies around Antarctica?

    Some interesting contradictions here. If they state that cooling seas draw down CO2 then they are implying also the opposite – that warming oceans will release CO2. But following this logically would lead to a questioning of whether the current CO2 rise really is from fossil fuel burning. It might be from outgassing from warming oceans.

    Reading between the lines in articles like this one senses disquiet in the Climagesterium.

  15. oldbrew says:

    It might be from outgassing from warming oceans.

    Yes, the fizzy drink analogy.

  16. p.g.sharrow says:

    Any real scientist or engineer in gases / liquids would know that the amount of a gas held in a saturated liquid is Directly related to the temperature of the mixture. Heat it up and the gases boil out, a cooling liquid sucks the gases into it. The bottom line is, It is a matter of energy and not really temperature as the exchange moves energy even before temperature changes…pg.