Thursday , January 20 2022

Polar ice sheets can fall & # 39; even if global warming is limited


People are "very close" to trigger irrecoverable change in the Earth's planetary ice sheets, says Professor Otago University.

Antarctica and Greenland ice sheets may even fall if global warming caused by people is limited before reaching 2 Celsius degrees above pre-industrial revolution levels, according to a new research review. They will shrink at rates similar to the last decade, and can be faster.

Both have "tipping points" at or slightly higher than 1.5 to 2C which will cause unexpected ice loss in Las Vegas and the fall of the large drainage basins in Antarctica.

It means that the ice sheets are in great trouble, even if we can adhere to the Paris Agreement goals that restrict global average temperatures to "below 2 ° C above pre-industrial levels and follow efforts to restrict & The temperature rise to 1.5C above pre-industrial levels ".

* Arctic ice is quite cutting off to the north of the Greenland
* Antarctica eerie song – melting
* & # 39; Future grim & # 39; on the horizon as Antarctic ice melted triple

Professor Christina Hulbe, from the University of Otago Surfing School, said the work had "one clear message: we are very close to triggering an irreversible change in the Earth's planetary ice leaflets".

Antarctica and Greenland ice sheets may shrink at rates similar to the last decade, and possibly faster.


Antarctica and Greenland ice sheets may shrink at rates similar to the last decade, and possibly faster.

Rainy ice caps mean raising sea levels.

Even if we meet Paris targets and keep warming up in a check, we are still committed to losing continuous ice over the 21st century, and as it continues to raise sea level, he said Hulbe.

"We will add to this warning that some of the tipping processes may already be called, at least in some parts of Antarctica but understand that more work is needed in detail."

The review found that ice sheets would continue to lose mass similar to the last decade.

However, they could not rest that they could even fall faster.

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

Associate Professor Rob McKay, of the University of Wellington Antarctica Research University, said that after the tipping points were reached in each polar ice leaflet, "a destination may become unstable".

Ice and snow in Antarctica, captured by the Nasa plane as it flies above as part of Operation Icebridge, which observes ice changes.


Ice and snow in Antarctica, captured by the Nasa plane as it flies above as part of Operation Icebridge, which observes ice changes.

Like Hulbe, he even said that if the world met the Paris climate agreement targets, we would be very close to the point without returning for a quick retreat.

Sadly, but McKay also noted that it will not happen overnight.

"Although this melting will play over hundreds for thousands of years, it is clear from this work, the more we will overlap with the target 1.5C, the this faster ice leaflet will be faster. "


Hulbe said it had been known for some time that both ice sheets were exposed to climate change and that the physical processes that controlled them had tipping points – beyond thresholds that were ensured that ice sheets shrink no matter what we do next.

"Which processes are most important in the north and south, and the different research groups use somewhat different methods to represent in computer models. But there are & # 39; All computer models point at the same address: the threshold for unwanted ice loss in the Greenland and Antarctica is somewhere between 1.5 and 2C global mean warming. We are already just over 1C warming up.

"When the models vary, how quickly the ice sheets are relinquishing once the threshold is crossed. Differences between models are useful even though showing which processes and which regions need more study.

"New Zealand is an international leader in this type of research. We carry out challenging fieldwork in Antarctica and South Ocean and we are actively involved in building better models to predict what will happen next and how it will play to not here at home. "


Professor James Renwick, Victoria University: "What's happening with ice and climate, it's all down to human activity. We're causing this. ; r power in our hands to give us the best to do what we've been doing in the last 100 years and moving to renewable energy, giving us the best to emit fossil fuels, that's what this.

"This should be another call to act, that the humanity has the power to change the way we operate".

"The latest modeling results suggest that some time in the next 50 years may come to a threshold where a Ice and Antarctic shelf at least starts to dissolve irrecoverable. And once it starts you can not suspended – and parts of the Iceland ice sheet, the same story.

"So we may even close about 5m sea level rise if we are restricting global warming to 2C.

Everyday, people came to emit greenhouse gases with those tipping points closer, he said.

Seawash breaks up in Ross Ross, Antarctica.


Seawash breaks up in Ross Ross, Antarctica.

But New Zealand had the potential to lead the way on climate action.

"We can respond quickly that we can show the world what can be done. That argument is not very small so we can not do anything relevant to it America Cup or the World Rugby Cup in some areas although we are very small.

"There is no reason we could not do it on climate change, on renewable energy, on smart technologies. Just thinking, it's just a matter of will."

The review paper, which is a summary of the current understanding of a research-based topic, was published in the Nature magazine.

Professor Tim Naish, from the Antarctic Research Center at Victoria University of Wales, said that it was timely, given the IPCC's Special Report on "Global Warming of 1.5C" recently and given the world is close to warming up 1.5C.

"With no direct carbon extraction of the atmosphere, we are not likely to avoid that."

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