Early Holocene Laurentide Ice Sheet Retreat Influenced Summer Atmospheric Circulation in Baffin Bay

Changes in ice-sheet size impact atmospheric circulation, a phenomenon documented by models but constrained by few paleoclimate records. We present sub-centennial-scale records of summer temperature and summer precipitation hydrogen isotope ratios (& delta;H-2) spanning 12-7 ka from a lake on Baffin Island. In a transient model simulation, winds in this region were controlled by the relative strength of the high-pressure systems and associated anticyclonic circulation over the retreating Greenland and Laurentide ice sheets. The correlation between summer temperature and precipitation & delta;H-2 proxy records changed from negative to positive at 9.8 ka. This correlation structure indicates a shift from alternating local and remote moisture, governed by the two ice-sheet high-pressure systems, to only remote moisture after 9.8 ka, governed by the strong Greenland high-pressure system after the Laurentide Ice Sheet retreated. Such rapid atmospheric circulation changes may also occur in response to future, gradual ice-sheet retreat.

Automated summary

Changes in ice-sheet size have an impact on atmospheric circulation, as shown by models and limited paleoclimate records. A new study on Baffin Island provides records of summer temperature and precipitation isotopes that span from 12-7 thousand years ago. The results indicate that the correlation between temperature and precipitation changed at 9.8 thousand years ago, suggesting a shift in moisture patterns controlled by ice-sheet high-pressure systems. These findings have implications for future ice-sheet retreat and associated atmospheric circulation changes.