Solar input to high latitudes and the global ice volume

Posted: March 8, 2019 by oldbrew in History, Ice ages, research, solar system dynamics
Tags: ,

Theorists take another look at the mechanisms that may or may not be important regulators of Earth’s ice ages.

Climate Etc.

by Donald Rapp, Ralf Ellis and Clive Best

A review of the relationship between the solar input to high latitudes and the global ice volume over the past 2.7 million years.

View original post 4,521 more words

  1. oldbrew says:

    Ralph Ellis (one of the 3 authors) had a paper featured at the Talkshop a few years ago:

    Albedo regulation of Ice Ages, with no CO2 feedbacks

  2. Stephen Richards says:

    It’s likely that only one mechanism controls the ice – interglacials. The Sun.

  3. oldbrew says:

    Stephen Richards says:
    March 9, 2019 at 8:30 am
    – – –
    Yes, the albedo can’t regulate itself.

  4. oldbrew says:

    Why ice ages became longer and more intense
    MARCH 9, 2019

    Researchers say they have confirmed the crucial role of the Antarctic Ocean during periods of climate change. Over the past million years, less frequent mixing of deep and surface waters may have influenced the transition to longer, more intense ice ages.

    During the mid-Pleistocene transition period, which began one million years ago, ice ages extended and became more powerful; the frequency of their cycles increased from 40,000 years to 100,000 years.

    One of the keys to this phenomenon lies in the deep waters of the Southern Ocean surrounding Antarctica, according to research published in the journal Scienceexternal link, carried out by a team led by professor Samuel Jaccard from the University of Bern.

    More specifically:
    The scientists looked in details at the difference in salinity and temperature between the surface and deep waters, which determine the intensity of the mixing. During the transition to longer ice ages the surface waters became simultaneously colder and less salty. Consequently, the mixing of water layers decreased considerably during ice ages.

    The residence time of Southern Ocean surface waters and the 100,000-year ice age cycle

  5. pyromancer76 says:

    An addition to Oldbrew’s comment. I think one needs to check the movement of plates around the southern hemisphere over time. When the Southern ocean became “isolated,” Earth might have become colder. Just an addition to all the other causes.

    Thanks for this site and for all the commenters, too. A bastion for the scientific method and sanity.

  6. rappolini says:

    Stephen Richards says “It’s likely that only one mechanism controls the ice – interglacials. The Sun.” He gives no basis for this. It is just a prognostication like “the Great Oz has spoken”.

    The old brew compounds the felony by saying “albedo cannot regulate itself”. But external effects like dust deposition can change the albedo remarkably.

    None of these comments are relevant to the original paper. They are just sidetracks.

  7. oldbrew says:

    rappolini says:
    March 9, 2019 at 5:46 pm
    – – –
    From conclusion (8) of the paper:

    In contrast, Antarctic ice sheets had reached their natural continental limit of expansion and so their albedo feedback remained constant, thus allowing the ever expanding NH ice sheet albedo to dominate global climate feedbacks.

    Comment: Obviously dust deposition does not cause ‘ever expanding NH ice sheet albedo’. Therefore something else must cause it, before the dust comes along.

    allowing…albedo to dominate global climate feedbacks – commenting on that is a ‘sidetrack’?

    Comment: Anyone saying albedo does this or that needs to explain the underlying forces.

  8. J Martin says:

    The authors seem to have got hung up on precession, which the earth does not or at least only to a minor extent. I think they need to read through this link and then re-write their paper.

  9. oldbrew says:

    JM – there’s more than one precession, e.g. apsidal (perihelion) precession, axial (tilt) precession.

    Why Phi? – a unified precession model

    3 apsidal = 13 axial = 16 combined
    Three types of year: anomalistic, sidereal, tropical