A new study offers essential clues about what should happen next from climate change. Using geological records of past sea levels, scientists shed light on ice sheets responsible for a rapid pulse of sea-level rise in Earth’s recent past.
The study conducted by Durham University suggests that previous ice loss events could have caused sea-level rise at rates of around 3.6 meters per century. The records also reveal that sea levels rose at ten times the current rate due to Meltwater Pulse 1A (MWP-1A), a 500 year, ~18-meter sea-level rise event around 14,600 years ago.
The geological sea-level data and state-of-the-art modeling techniques help scientists reveal the sources of MWP-1A. Strangely, the majority of the meltwater seems to have begun from former North American and Eurasian ice sheets, with negligible commitments from Antarctica, absorbing divergent perspectives on the former.
In addition to flooding vast areas of low-lying land, this unusual discharge of freshwater into the ocean—comparable to melting an ice sheet twice the size of Greenland in only 500 years—will have disrupted ocean circulation, with knock-on effects for global climate. Knowing the source of the meltwater will improve the accuracy of climate models used to replicate the past and predict changes in the future.
The outcomes are significant for our comprehension of ice-sea environment cooperations, which assume a critical part in forming earthbound climate designs. The discoveries are especially ideal with the Greenland ice sheet quickly dissolving, adding to increased sea levels and changes to global ocean circulation.
Lead author Yucheng Lin, in the Department of Geography at Durham University, notes: “Despite being identified over 30 years ago, it has been surprisingly challenging to determine which ice sheet was the major contributor to this dramatic rise in sea levels.”
“Previously, scientists tried to work out the source of the sea-level rise based on sea-level data from the tropics, but the majority of those studies disagreed with geological records of ice sheet change.”
Co-author Dr. Pippa Whitehouse, in the Department of Geography at Durham University, said, “The technique we have used allows us to dig into the error bars on the data and explore which ice-melt scenarios were most likely.
“We found that most of the rapid sea-level rise was due to ice sheet melt across North America and Scandinavia, with a surprisingly minor contribution from Antarctica.”
“The next big question is to work out what triggered the ice melt and what impact the massive influx of meltwater had on ocean currents in the North Atlantic. This is very much on our minds today—any disruption to the Gulf Stream, for example, due to melting of the Greenland Ice Sheet, will have significant consequences for the UK climate.”
- Lin, Y., Hibbert, F.D., Whitehouse, P.L. et al. A reconciled solution of Meltwater Pulse 1A sources using sea-level fingerprinting. Nat Commun 12, 2015 (2021). DOI: 10.1038/s41467-021-21990-y