A reconciled solution of Meltwater Pulse 1A sources using sea-level fingerprinting

The most rapid global sea-level rise event of the last deglaciation, Meltwater Pulse 1A (MWP-1A), occurred similar to 14,650 years ago. Considerable uncertainty regarding the sources of meltwater limits understanding of the relationship between MWP-1A and the concurrent fast-changing climate. Here we present a data-driven inversion approach, using a glacio-isostatic adjustment model to invert for the sources of MWP-1A via sea-level constraints from six geographically distributed sites. The results suggest contributions from Antarctica, 1.3 m (0-5.9 m; 95% probability), Scandinavia, 4.6 m (3.2-6.4 m) and North America, 12.0 m (5.6-15.4 m), giving a global mean sea-level rise of 17.9 m (15.7-20.2 m) in 500 years. Only a North American dominant scenario successfully predicts the observed sea-level change across our six sites and an Antarctic dominant scenario is firmly refuted by Scottish isolation basin records. Our sea-level based results therefore reconcile with field-based ice-sheet reconstructions. Meltwater Pulse 1A was the most rapid global sea-level rise event during the last deglaciation, but the source of the freshwater causing this rise is debated. Here, the authors use a data-driven inversion approach to show that the North American and Eurasian Ice Sheets were the dominant contributors.

Automated summary

The study suggests that the North American and Eurasian Ice Sheets were the primary contributors to the rapid global sea-level rise event, Meltwater Pulse 1A, during the last deglaciation. The results based on sea-level constraints align with field-based ice-sheet reconstructions, supporting the idea that the freshwater causing the sea-level rise mainly came from North America and Eurasia.