Talk by Michiel Helsen, post-doctoral researcher at University of Utrecht – Niels Bohr Institute - University of Copenhagen

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Talk by Michiel Helsen, post-doctoral researcher at University of Utrecht

Coupled regional climate - ice sheet simulation shows limited Greenland ice loss during the Eemian


Abstract
During the last interglacial period (Eemian, 130 – 115 ky BP) eustatic
global sea level likely peaked at >6 m above the present-day level, but
estimates of the contribution of the Greenland ice sheet vary widely.
Here we usean asynchronously two-way coupled regional climate – icesheet
model, which includes physically realistic feedbacks between the
changing ice sheet topography and climate forcing. Our simulation
results in a contribution from the Greenland ice sheet to the Eemian sea
level highstand between1.2 and 3.5 m, with a most likely value of 2.1 m.
Simulated Eemian ice loss in Greenland is dominated by the rapid retreat
of the southwestern margin; two-thirds of the ice loss occurred south of
70˚N. The southern dome survived the Eemian and remained connected to
the central dome. Large-scale ice sheet retreat is prevented in areas
with high accumulation. Our results broadly agree with ice core inferred
elevation changes and marine records, but it does not match with the
ice-core derived temperature record from northern Greenland. During
maximum Eemian summertime insolation, Greenland mass loss contributed
~ 0.5 m ky-1 to sea level rise, 24% of the reconstructed total rate of
sea level rise. Next to that, a difference of >3 m remains between our
maximum estimate of the Greenland contribution and the reconstructed
minimum value of the global eustatic Eemianhighstand. Hence, the
Antarctic ice sheet must also have contributed significantly to this sea
level highstand.