Wednesday , February 24 2021

Polar ice sheets can "collapse" even if global warming is limited



A professor at the University of Otago says that people are "very close" to cause irreversible changes in the Earth's polar ice circles.

According to a new study, Antarctica and Greenland ice chalk can collapse even if human-induced global warming is limited before it reaches 2 degrees Celsius above pre-industrial revolutionary levels. They will fall to rates similar to the last decade, and possibly faster.

And both have "failure points" at or slightly above 1.5-2 C, which will cause irreversible loss of ice in Greenland and the collapse of the main drainage basins in Antarctica.

This means that both ice tanks are in great difficulty, even if we can meet the objectives of the Paris Agreement to limit the average global temperature "significantly below 2 ° C above pre-industrial levels and aiming to limit the temperature increase to 1.5 ° C compared to pre-industrial levels."

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Professor Christina Hulbe of the Otago School of Education School said that there was "one clear message: we are very close to causing irreversible changes in the Earth's polar ice bows".

The Antarctic and Greenland ice sheets can shrink at rates similar to the last decade, and possibly faster.

JOE RAEDLE / GETTY IMAGES

The Antarctic and Greenland ice sheets can shrink at rates similar to the last decade, and possibly faster.

Melting ice biscuits means raising sea levels.

Even if we meet the Paris targets and continue to test the warming, we are still committed to continue to lose ice in the 21st century and continued to increase sea levels, Hulbe said.

"I would add that some disposal processes may already have been used at least in some places in Antarctica, but realizing that more detail is needed."

The report found that ice tanks continue to lose weight similar to the last decade.

However, this does not preclude them from collapsing even more quickly.

In June, the analysis showed that the rate of melting in Antarctica has tripled since 2012.

Associate Professor Rob McKay, Associate Professor at the University of Victoria, Antarctic Research Center in Wellington, said that after reaching each polar ice test, the points could be reached, "asylum potentially becoming unstoppable".

Ice and snow in Antarctica, taken by a NASA aircraft, as the flying airplane flew as part of Operation Icebridge, which observed changes in ice.

NASA / EARTH OBSERVATORY

Ice and snow in Antarctica, taken by a NASA aircraft, as the flying airplane flew as part of Operation Icebridge, which observed changes in ice.

Like Hulbe, he said that even if the world were to meet the objectives of the Paris climate agreement, we would be very close to the return to accelerated withdrawal.

This is serious, but McKay also said that this would not happen just one night.

"Although this melting will take hundreds or thousands of years, this work shows that the more we exceed the 1.5C targets, the faster it will speed up the ice sheets."

TIPPING POINTS

Hulbe said that it's known for some time that both ice cubes are sensitive to climate change and that the physical processes they manage are overcome points – the limits within which refrigerators should be reduced regardless of what we are doing next.

"Which processes are largely different in the north and south, and different research groups have rather different approaches to represent them in computer models. But all computer models point to the same direction: the threshold for irreversible ice loss in both Greenland and Antarctica is somewhere between 1.5 and 2C global warming. We already have a little more than 1C warming up.

"If the patterns are different, just how fast the ice sheets are reset when the threshold is crossed. Modeling differences are useful because they show which processes and which regions need more research.

"New Zealand is an international leader in this type of research. We are challenging fieldwork in the Antarctic and the Southern Ocean, and we are actively involved in building better models to predict what will happen next and how we will be here at home."

HUMAN ACTIVITIES

Professor James Renvick, Wellington University of Victoria: "What is happening with ice and climate, it is completely dependent on human activity, we are causing it. We can stop what we have done in the last 100 years and move on to renewable energy by stopping fossil fuels from being what is it all about?

"This is another call for action that mankind has the right to change the way we work."

"The latest modeling results show that over the next 50 years, for some time, we could reach the threshold where at least the Atlantic Ice Antarctic Iceberg spills irreversibly. And when it starts, you can not stop it – and the iceberg of the Greenlandic part is the story itself.

"So, we could block an increase of about 5 m above sea level, even if we would limit global warming to 2 ° C.

He said that people are emitting greenhouse gases every day.

The sea ice breaks in the Ross Sea, Antarctica.

IAIN MCGREGOR / STUFF

The sea ice breaks in the Ross Sea, Antarctica.

But New Zealand has the potential to move towards climate action.

"We can react quickly, we can show the world what can be done. The argument that" we are small so we can not do anything "does not seem to apply to the American Cup or World Cup rugby. In some areas, although we we are small.

"There's no reason we could not do that in terms of climate change, renewable energy and smart technologies. It's just a way of thinking, and it's just a willpower."

The review document, which is a summary of the current subject matter of the study, was published in the journal Nature.

Tim Naish, Antarctic Research Center at New York's Victorian University, said it was timely given the recent release of the IPCC Special Report on "1.5C Global Warming," and given that the world was close to 1.5C.

"If we do not find a degree of carbon dioxide extraction from the atmosphere, we are unlikely to miss it."


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