The Weekend Wonk: Eric Rignot – Update on Ice Sheets

July 26, 2020

Recent talk – 2019 – from Eric Rignot.
If you want the most recent, reliable take, this is your guy.

Big thanks to Climate State for posting this.

8 Responses to “The Weekend Wonk: Eric Rignot – Update on Ice Sheets”

  1. rhymeswithgoalie Says:

    I haz lernd today.
    Apparently the “lubrication” factor of the meltwater fed to the base via the moulins dissipates as the water spreads out.
    Still, it’s a quick way to transfer heat through the ice.

    • grindupbaker Says:

      I’ve posted above my standard 1-trick pony catch all mixture of notion & hypothesis about ENSO boosting again but the circumpolar wind regime to contract is speculative (as is Arctic sea ice) because an Aussie lady scientist said something that supported ENSO boost as the cause but then Aussie Matthew H. England gave some different cause I don’t remember (but perhaps there’s one of those “teleconnections”).

    • grindupbaker Says:

      Not likely a quick way to transfer heat through the ice because the ice must be warmest at the base (geothermal), coldest likely closer to surface than base, then warming again from there to surface.

  2. rhymeswithgoalie Says:

    This is new, at least to me (~6:05):
    Several factors (including AGW and ozone hole) is causing the circumpolar wind regime to contract, become faster, push colder fresh surface water northwards, which pulls more warm bottom water to Antarctica.

    Crikey, another positive feedback.

    • dumboldguy Says:

      Is anyone keeping track of the positive feedbacks? Are there more appearing, are they getting stronger?

      • rhymeswithgoalie Says:

        Well, there’s that circumpolar regime,
        arctic ice/snow melt reducing albedo and increasing sun heat absorption,
        melting of permafrost producing more GHG,
        and—probably a long way away—the accelerated melt of sea-bed clathrates.

    • grindupbaker Says:

      Ice melt at depth at the face must itself be a positive feedback because fresher water if less dense than saltier water at the ~same temperature which must cause pressure anomaly at depth.

  3. grindupbaker Says:

    *** PART 2 OF 2 ***
    Here’s the sequence of events, some definitely linked and others possibly linked:
    – 1995 AD the start. Pacific Ocean easterly trade winds began increasing.
    – Pacific Ocean easterly trade winds have increased 30% (1 m/s) since 1995 AD.
    – The ocean heat content (OHC) anomaly rate DOUBLED at ~1999 AD (ocean started warming twice as fast as before ~1998 AD
    ).
    – Huge 1997/98 El Nino started soon after 1995 AD
    .
    – Arctic Ocean summer sea ice extent loss rate massively increased at 1997.5 AD as seen in a plot at 9:15 at https://www.youtube.com/watch?v=sCEawfpDoD0&t=42s
    – GMST increase slowed. ENSO change caused the “pause” or “hiatus” (that’s why global warming” is 0.11 degrees less than in models).
    – GMST ==El Nino years== started pulling ahead of La Nina faster at +0.23 degrees / decade vs +0.165 degrees / decade.
    – Sea level change rise (SLR) of the ==western== equatorial Pacific Ocean has been much higher than the global average because the stronger Pacific Equatorial trade winds are pushing the water westwards harder than pre-1995 AD
    – Greenland ice sheet (GrIS) mass loss more than doubled in 1997 AD,
    – Arctic region warming at latitude 67N 1958-2019 sped up to +0.94 degrees / decade from a lower earlier rate ~1996-1998
    – Southern westerlies strengthened & tightened on Antarctica soon after (perhaps the Antarctic circumpolar westerlies began strengthening & tightening then but I haven’t pinned ENSO as the cause yet).
    – Actual “global warming” is 0.11 degrees less than model global warming because the WG1 climate scientists didn’t replicate that Pacific Ocean – Atlantic Ocean wind coupling effect in the CMIP models. I don’t know whether they’ve corrected that in CMIP6.
    – Almost certainly has affected the Indian Ocean dipole with this additional wind push westward so will likely increase drought in Australia due to moving the warm rising air more often further to the west than before.
    —————–
    All happened soon after 1995 AD
    when the tropical Pacific Ocean easterly trade winds started having higher average speed and boosting the ENSO.
    —————-
    The Tropical Atlantic Ocean surface has warmed and has increased the intensity of the Tropical Pacific Ocean trade winds by 50% in under 30 years because the atmospheric circulation is coupled between the Tropical Atlantic Ocean and the Tropical Pacific Ocean, but the Tropical Atlantic Ocean and the Tropical Pacific Ocean aren’t coupled because there’s land in the way
    ENSO is a massive feature of Earth’s climate and the GMST trends have been:
    +0.13 degrees / decade: UAH lower troposphere 1979-2017
    +0.17 degrees / decade: RSS lower troposphere 1979-2017
    +0.165 degrees / decade: Surface La Nina & ENSO-neutral years 1970-2014 (me from GISTEMP)
    +0.20 degrees / decade: Surface El Nino years 1966-1995 (me from GISTEMP)
    +0.23 degrees / decade: Surface El Nino years 1995-2014 (me from GISTEMP, high uncertainty, sparse & varied data points)
    +0.18 degrees / decade: Surface average 1966-2014 (GISTEMP)
    +0.11 degrees / decade: Ocean surface 1966-2014 (GISTEMP)
    +0.047 degrees / decade: Ocean 0-300M depth 1966-2010 89 / 432 = 0.206 (me from various, Hadley, ORAS4, talk plots etc.)
    +0.030 degrees / decade: Ocean 300-700M depth 1966-2010 76 / 576 = 0.132 (me from various, Hadley, ORAS4, talk plots etc.)
    +0.026 degrees / decade: Ocean 700-1000M depth 1966-2010 (me from various, Hadley, ORAS4, talk plots etc.)
    +0.15 degrees total increase: Ocean 0-1000M depth (me from various, Hadley, ORAS4, Matthew England talk plots etc.)
    —————-
    +0.009 degrees / decade: Ocean 700-2000M depth 1966-2010 77 / 1872 = 0.0411 (me from various, Hadley, ORAS4, talk plots etc.)
    Note the +0.23 degrees / decade for El Nino years since 1995 and only +0.165 degrees / decade for La Nina & ENSO-neutral years. A big difference.


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