SOURCES OF SEA-LEVEL RISE DURING THE LAST DEGLACIATION

The rise in sea level across the last deglaciation provides an integrated record of global ice-sheet retreat and associated meltwater discharge. Sea-level rise was not constant, with intervals of reduced rise during the Oldest Dryas (~18.5-14.5 ka) and Younger Dryas (~12.9-11.7 ka) cold events and higher rates of rise during the Bølling warm period (~14.6-14.0 ka). In conflict with the paradigm that increased meltwater discharge from Northern Hemisphere ice sheets slows Atlantic meridional overturning circulation cooling the North Atlantic region, North Atlantic cold periods are aligned with intervals of slower sea-level rise whereas North Atlantic warm periods are concurrent with accelerated sea-level rise. However, the location of meltwater discharge to global oceans relative to regions of deepwater formation may play an important role in governing the impact of meltwater discharge on ocean circulation and climate. We will discuss the contributions of different ice sheets to global sea-level rise across the last deglaciation, focusing on the timing of rapid retreat of individual ice sheets relative to faster and slower rates of sea-level rise. We will show that the Oldest Dryas and Younger Dryas cold periods were associated with meltwater discharged directly to the northern North Atlantic near regions of deepwater formation. In contrast, meltwater during the Bølling was discharged at locations more removed from northern North Atlantic regions of deepwater formation.