One intuitively expects that if enough of Greenland melts to raise global sea levels by, say, three centimetres, that rise will occur everywhere more or less simultaneously. Detlaf Stammer, of Hamburg University, has suggested otherwise. His research on meltwater data since 1948 shows that meltwater forms a ’slow wave’ of “rising sea levels that gradually works its way south from Greenland, down the American coast, reaching the tip of southern Africa after about a decade.”
Fifty years after any Greenland melting occurs, Stammer’s model suggests that sea level rise will be thirty times greater around Greenland and the east coast of North America than it will be in the Pacific ocean. If true, this will have a big effect on the kind of climate change adaptation planning that needs to take place. Everyone is exceptionally worried about Bangladesh right now, but perhaps they should be more immediately concerned about Florida and the Maritimes.
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What makes the process of balancing out so slow?
I’m a bit confused about the possible rise in sea level that may be caused by global warming. I know that in general water expands when warmed, and that is one cause of sea level elevation with respect to global warming. The larger cause for alarm seems to be the melting or collapse of the polar ice caps. I recently read an article that warned that Antarctica, which stores 70 percent of the world’s fresh water, could lose the Ross Ice Shelf (a block of ice the size of France) suddenly and without warning and “that its collapse would make sea levels rise by at least 5 meters, with other estimates predicting a rise of up to 17 meters.” My question is how quickly would such a rise register?
Ice Age lesson predicts a faster rise in sea level
If the lessons being learned by scientists about the demise of the last great North American ice sheet are correct, estimates of global sea level rise from a melting Greenland ice sheet may be seriously underestimated. Writing this week (Aug. 31) in the journal Nature Geoscience, a team of researchers led by University of Wisconsin-Madison geologist Anders Carlson reports that sea level rise from greenhouse-induced warming of the Greenland ice sheet could be double or triple current estimates over the next century.
“We’re not talking about something catastrophic, but we could see a much bigger response in terms of sea level from the Greenland ice sheet over the next 100 years than what is currently predicted,” says Carlson, a UW-Madison professor of geology and geophysics. Carlson worked with an international team of researchers, including Allegra LeGrande from the NASA Center for Climate Systems at Columbia University, and colleagues at the Woods Hole Oceanographic Institution, the California Institute of Technology, University of British Columbia and University of New Hampshire.
Scientists have yet to agree on how much melting of the Greenland ice sheet — a terrestrial ice mass encompassing 1.7 million square kilometers — will contribute to changes in sea level. One reason, Carlson explains, is that in recorded history there is no precedent for the influence of climate change on a massive ice sheet.