Understanding climate
for the benefit of society

Talk by Benoit Lecavalier on Thursday June 1

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We have the pleasure of inviting you all to Benoit Lecavaliers talk this Thursday (June 1st) at 15:00 in the  Undervisningsrom 4060in 4th floor, West Wing GFI. The talk will be on his newest paper published last week with the title "A high Arctic Holocene temperature record and Greenland ice sheet evolution ". For those of you who haven't met Benoit yet, he's a visiting PhD student from Memorial University, St. John’s, Canada until mid June, at the moment located in the top floor in the West Wing.

 

Abstract:
We present a revised and extended high Arctic air temperature reconstruction from a single proxy that spans the past ~12,000 years (up to 2009 CE). Our new reconstruction from the Agassiz ice cap (Ellesmere Island, Canada) indicates an earlier and warmer Holocene Thermal Maximum with early Holocene temperatures that are 4-5 oC warmer compared to a previous reconstruction and regularly exceed contemporary values for a period of ~3,000 years. Our results show that air temperatures in this region are now at their warmest in the past 6,800–7,800 years and that the recent rate of temperature change is unprecedented over the entire Holocene. The warmer early Holocene inferred from the Agassiz ice core leads to an estimated ~1 km of ice thinning in Northwest Greenland during the early Holocene using the Camp Century ice core. Ice modeling results show that this large thinning is consistent with our new air temperature reconstruction. The modeling results also demonstrate the broader significance of the enhanced warming, with a retreat of the northern ice margin behind its present position in the mid Holocene and a ~25% increase in total Greenland ice sheet mass loss (~1.4 m sea-level equivalent) during the last deglaciation, both of which have implications for interpreting geodetic measurements of land uplift and gravity changes in northern Greenland.