Ancient sea-level rise was driven by melting in North America and Eurasia, not Antarctica, reshaping climate models and warnings for future change.
It is well known that climate-induced sea level rise is a major threat. New research has found that previous ice loss events could have caused sea-level rise at rates of around 3.6 meters (12 feet) per century, offering vital clues as to what lies ahead should climate change continue unabated.
A team of scientists, led by researchers from Durham University, used geological records of past sea levels to shed light on the ice sheets responsible for a rapid pulse of sea-level rise in Earth’s recent past.
Geological records tell us that, at the end of the last ice age around 14,600 years ago, sea levels rose at ten times the current rate due to Meltwater Pulse 1A (MWP-1A); a 500-year, ~18-meter (59-foot) sea-level rise event.
Until now, the scientific community has not been able to agree about which ice sheet was responsible for this rapid rise, with the massive Antarctic Ice Sheet being a likely suspect, but some evidence pointing towards ice sheets in the Northern Hemisphere.
Breakthrough From Northern Hemisphere Ice Sheets
The new study uses detailed geological sea-level data and state-of-the-art modeling techniques to reveal the sources of MWP-1A. Interestingly, most of the meltwater appears to have originated from the former North American and Eurasian ice sheets, with minimal contribution from Antarctica, reconciling formerly disparate views.
In addition to flooding vast areas of low-lying land, this unparalleled 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 that are used to replicate the past and predict changes in the future.
The results are important for our understanding of ice-ocean-climate interactions which play a significant role in shaping terrestrial weather patterns. The findings are particularly timely with the Greenland ice sheet rapidly melting, contributing to a rise in sea levels and changes to global ocean circulation.
A New Method Using Scottish Lake Records
Of the findings, 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.
Our study includes novel information from lakes around the coast of Scotland that were isolated from the ocean due to land uplift following the retreat of the British Ice Sheet, allowing us to confidently identify the meltwater sources.”
Co-author Dr. Pippa Whitehouse, in the Department of Geography at Durham University, said “The technique we have used allows us to really 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 small 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.”
Rising sea levels due to warming climate pose a great risk to society, improving our understanding of why and how fast change could happen will help us plan for the impacts.
Reference: “A reconciled solution of Meltwater Pulse 1A sources using sea-level fingerprinting” by Yucheng Lin, Fiona D. Hibbert, Pippa L. Whitehouse, Sarah A. Woodroffe, Anthony Purcell, Ian Shennan and Sarah L. Bradley, 1 April 2021, Nature Communications.
DOI: 10.1038/s41467-021-21990-y
Yucheng Lin is funded by a Durham University – China Scholarship Council joint scholarship.
The Scotland data was collected and analyzed by Durham University researchers, funded by the Natural Environment Research Council.
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4 Comments
“… but some evidence pointing towards ice sheets in the Northern Hemisphere.”
What was the first clue? The fact that a North American ice sheet(s) that was perhaps a mile and a half thick in NE Canada, and extended well into the eastern USA, is no longer present? Or that the Channeled Scablands in Washington provides evidence of a massive glacial lake catastrophically draining across Washington and emptying into the Pacific Ocean?
A simple calculation of the volume of ice in North America should indicate whether that accounts for an 18 meter rise in sea level, or if a similar amount of ice would have to come from Antarctica. If the Wisconsin Ice Sheet doesn’t provide quite enough water, one could add in the glaciers in the Sierra Nevada and Rocky Mountains before resorting to estimating the Antarctic contribution. Then there are the pesky Eurasion Ice Sheets as well.
“… with the Greenland ice sheet rapidly melting, …”
At current rates, calculations suggest that it will take about 15,000 years for the Greenland ice sheet to melt. I wouldn’t characterize that as “rapidly!”
I’d like to point out that the Glaciars melting may be being caused by Government’s interest in freshwater vS. drought vS. nuclear energy demand for water vS. nuclear energy waste of water adding up to glacial water being bottled, from sources that feed the Glaciars. And not because of some supposed climate change or earth warming.
It’s like diverting water from the freezer ice maker to the floor and then blaming the freezer for melting water and not making ice cubes. The. Blaming the manufacture if the freezer when you yourself aren’t recognizing and noone else is recognizing that the water is being diverted, rather than making Glaciars!
It’s sad and at this rate the future looks bleak and filled with tyrants, who are blatantly decieving us for mere power gain.
Could someone look into Bottling Glacial Water at the source, and find out, just how much has been bottled, and exactly what role these glacial water bottling company’s are playing in Glaciars deplenishing and just how much water has been stolen from the Glaciars?
Glaciars sit in the ocean and some in mountain peaks, very warm areas. They naturally melt, but other than glacial water bottling companies, noone has touched the Glaciars, except for I believe the UK which haa been dragging Glaciars out into the ocean to study them.
There uses to be a slur about not touching the Glaciars. But now we supposedly have a need for freshwater, albeit rain is derived from water being evaporates out of the salt water into the atmosphere and then it pours down in to land at some point. There’s plenty of known science to desalinate the sea water right their, thanks to mother nature’s own ingenuity.
But somewhere along the line, scientists and the scientific community, as well as our global Nations leaders, are ignoring facts, trying to pour all of our money into their pockets, rather than actually help anyone other then themselves.
Ignore it research it or let others do it. But please stop blaming oil and natural gas! It sounds as ignorant as it looks. Just so nuclear can make money and hydrogen can deplete what water we have any further.
So, it has all happened before and with no influence from humans. Interesting…
Astronomical impact hypothosis. You’ll love it.
youtube.com/playlist?list=PLHY4t-R0YADjCkxB0PVYPqoSGrspbryHg