Weekly CASPO Seminar: Join us in Nierenberg 101 every Wednesday at 3:30 pm to hear about the latest and greatest in Climate, Atmospheric Sciences, and Physical Oceanography!
Dr. Mark England will present at talk titled "Global impacts of polar sea ice loss in the 21st century"
Under the current trajectory of greenhouse gas emissions, models project a large decline in both Arctic and Antarctic sea ice extent by the end of this century. Previous studies have shown that the effects of Arctic sea ice loss are not limited to the northern high latitudes, but reach into the lower latitudes. And yet, little is known about the effects of future Antarctic sea ice loss, notably outside of the southern high latitudes. I will present our work, from three different studies, investigating the response of the atmosphere and ocean to projected end-of-the-century Arctic and Antarctic sea ice loss using the fully coupled configuration of CESM-WACCM.
We show that both Arctic and Antarctic sea ice loss are likely to have far-felt impacts; both produce a mini-global warming signal; both have important effects on the tropospheric jet and both contribute significantly to changes in surface temperature and precipitation in the equatorial Pacific. We also demonstrate that the effect of sea ice loss over each pole will actually reach all the way to the other pole. Our model shows that an imposed sea ice loss in either hemisphere leads to a sizeable warming (~1°C) – and reduction of sea ice concentration and thickness – at the opposite pole. We explore the potential pathways in which this pole-to-pole signal can propagate. Lastly, we compare these fully coupled runs to identical runs using the same model in atmosphere-only mode and show ocean dynamics are vital for transporting the sea ice loss signal outside of the high latitudes.
Taken together, our results provide evidence for two important points: a) the effects of future Antarctic sea ice loss are likely just as large as the effects of Arctic sea ice loss and so need to be better understood, and b) this is an example where the polar regions can exert a considerable influence on the rest of the climate system.
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