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Research finds runoff from melting glaciers is giving climate change a boost

Research finds runoff from mel...
Melted glacial waters might themselves be a driver of global warming, a new study suggests
Melted glacial waters might themselves be a driver of global warming, a new study suggests
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Melted glacial waters might themselves be a driver of global warming, a new study suggests
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Melted glacial waters might themselves be a driver of global warming, a new study suggests

Melting glaciers are one runaway symptom of global warming, but new research suggests that they might also be a contributing factor. Scientists have discovered evidence of a previously unknown vicious circle, whereby melted glacial water alters the chemistry on the surface of the ocean and drives further glacial melting, in turn accelerating the rise of sea levels.

The new research was led by the Institute for Marine and Antarctic Studies (IMAS) at Australia's University of Tasmania. The team used ocean modeling to explore how glacial meltwater affects the upper layers of the sea, finding that it made the surface less salty and more buoyant. This hinders the deep mixing of ocean water that normally takes place in the winter, enabling the lower, warmer layers of the ocean to retain their heat.

"This process is similar to what happens when you put oil and water in a container, with the oil floating on top because it's lighter and less dense," explains IMAS PhD student Alessandro Silvano, who led the study. "The same happens near Antarctica with fresh glacial meltwater, which stays above the warmer and saltier ocean water, insulating the warm water from the cold Antarctic atmosphere and allowing it to cause further glacial melting. We found that in this way increased glacial meltwater can cause a positive feedback, driving further melt of ice shelves and hence an increase in sea level rise."

Furthermore, the team found that the meltwater also hampers the formation of denser water in certain parts of the Antarctic, bodies of water that normally sink and help drive ocean circulation that contributes to ocean absorption of heat and carbon dioxide.

"The cold glacial meltwaters flowing from the Antarctic cause a slowing of the currents which enable the ocean to draw down carbon dioxide and heat from the atmosphere," says Silvano. "In combination, the two processes we identified feed off each other to further accelerate climate change."

The researchers say this process may have played out in nature before, having been floated as an explanation for the dramatic sea level rise of about five meters per century (16.4 ft) at the end of the last glacial period around 15,000 years ago.

"Our study shows that this feedback process is not only possible but is in fact already underway, and may drive further acceleration of the rate of sea level rise in the future," says Silvano. "Currently the ice shelves resist the flow of ice to the ocean, acting like a buttress to hold the ice sheet on the Antarctic continent. Where warm ocean waters flow under the ice shelves they can drive rapid melting from below, causing ice shelves to thin or break up and reducing the buttressing effect. This process leads to rising sea levels as more ice flows to the ocean.'

The research was published in the journal Science Advances.

Source: University of Tasmania

12 comments
Lardo
Ah, so it's the glacier's fault. And here all this time I was told it was MY fault. Well, me and every other science denying, Neanderthal on the planet.
Gene Preston
This is not surprising. The loss of ice in the arctic has been accelerating for a couple of decades from the data produced by satellite GRACE. People are just now aware of the acceleration. If you keep up the acceleration all Greenland's ice will be gone by 2100.
Mike Vidal
There is one thing you can be sure of, that the climate changes, has been changing and will keep changing and there is not a damn thing we can do about it.
JustJim
Just more modeled alarmism. After the last ice age, of course we had sea level rise as the miles of ice on land melted refilling the oceans and lakes. Just before the ice age we probably had alarming sea level fall as the lakes and seas turned into ice on the land. Evaporation, then snow and ice. Sea level rise is not accelerating.
BOBP
Amazing discovery, that we have known about for many years in the northern hemishere, even mentioned by Al Gore in his 'convenient truth'. Is Tasmania maybe a liimttle too insular?
Johannes
Hey Mike and Jim, set aside your preconceptions and cognitive bias, have a look at https://www.youtube.com/watch?v=FBF6F4Bi6Sg and then come back with more evidence than just a "thing you can be sure of" and "probably". They're not really convincing arguments, are they.
christopher
Computer models are meaningless, and the assumptions are plain absurd. If the scientists had been funded by oil companies they would have modelled "everything is fine" just as easily. There is no balance in climate reporting, and nobody cares about the elephant in the room either: no matter what the situation, our species is powerless to make any *measurable* difference to where we're headed. For every low-emission human that's born, there's 10+ "don't give a shit" ones born too.
ljaques
OHMIGODWEREALLGONNADIEFASTER! Johannes, potholer54's video was the most measured and convincing yet, and I'll continue to do research, as he suggests, while I remain a bit of a denier.
Lamb
Christopher is correct. I Challenge anyone to debate me that climate change and the rising of sea levels have been going on for 100 000's of years, maybe more.
Catweazle
Yet another study based on computer games - er sorry, "climate models" that contradicts the clearly measurable changes in such things as rate of change of sea level - of which there isn't any - and mass of the Greenland and Antarctic ice caps - which is increasing on both. I'm unimpressed.