COMPARING OBSERVED AND MODELED HOLOCENE SEA LEVEL CHANGE IN GREENLAND

The Greenland Ice Sheet is one of the main contributors to modern global sea level rise. We can reduce the uncertainty in future sea level projections by understanding how the ice sheet responded to past changes in climate. The Holocene history (11,700 years ago to present) of vertical land movement around Greenland is important to investigate since ice sheet growth and decay influence glacial isostatic adjustment. We can use ice sheet and glacial isostatic adjustment models to predict vertical land movement and use field data to test the accuracy of the prediction. There are still spatial gaps in field data that need to be filled so we can better understand the history of the Greenland Ice Sheet and constrain model parameters. Here, we summarize the Holocene history of sea level changes around Greenland and present two data-model comparisons with new relative sea level curves from spatial data gaps. The pattern of relative sea level around Greenland suggests three sectors with a large amount of post glacial uplift (central west, north, and east; 120+ m), likely from increased ice cover during the Last Glacial Maximum. In south Greenland, where there was less ice cover, there was less uplift (~40 m) and a mid-Holocene sea level low stand; studies hypothesize that inland retreat of the ice sheet or the migration of the Laurentide forebulge could explain the low stand. Models predict that northwest Greenland experienced sea level rise since deglaciation, anomalous to all other Greenland sectors, but there is little field evidence to confirm this trend. Our two new relative sea level curves fill spatial data gaps in sea level history coverage. This enables us to test glacial isostatic adjustment models in understudied regions in northwest and northeast Greenland. This work will help refine glacial isostatic adjustment models and increase our knowledge of the sensitivity of the Greenland Ice Sheet to past and future climate change.