Scientists have issued a warning that the rules outlined in the Paris Agreement will not be enough to stop the collapse of the Greenland and Antarctic ice sheets.
Based on the Paris Agreement drawn up in 2015, countries agreed to limit global warming to less than 2degC compared to pre-industrial levels.
But new reports from Victoria University and Universite Libre de Bruxelles were published in Natural Climate Change found that both ice sheets might have a critical point at or slightly above the 1.5-2degC threshold.
Professor Tim Naish from Victoria University Wellington said the report was "very timely because of the latest release of the IPCC Special Report on Global Warming 1.5degC, and especially given that we were close to 1.5degC."
"Without direct carbon extraction rates from the atmosphere, we cannot avoid it," he said.
If the ice sheet collapses, reports say it could cause irreparable loss of mass and drainage. The impact of sea level rise will be a disaster for New Zealand.
New Zealand's promise under the Paris Agreement is to reduce emissions by 30 percent below 2005 levels by 2030. It was revealed last year that the costs for the New Zealand economy to meet the Paris Agreement target would be $ 1.4 billion annually for a decade.
"We are very close to triggering irreversible changes in the polar ice sheet of the Earth," Professor Christine Hulbe of Otago University said, commenting on the new report.
"The threshold for irreversible ice loss in Greenland and Antarctica is between 1.5 and 2degC globally which means warming. We've been a little more than warming 1degC.
"Even if we meet Paris's targets and keep paying attention to warming, we are still committed to continuing to lose ice during the 21st century, and with that the sea level continues to rise."
Rob McKay of the University of Victoria in Wellington noted that melting differs between hemispheres, with melting Greenland controlled by atmospheric warming and Antarctica by ocean warming.
But the temperature threshold for reaching these critical points in the two regions is between 1.5 and 2degC, he said, "indicating that even if we meet the Paris climate agreement target, we will be very close to the point of no hope for an accelerated retreat.
"While this melting will last for hundreds of thousands of years, it is clear from this work that the more we exceed the 1.5degC target, the faster the accelerated ice will melt this ice sheet."
The researchers concluded that urgent research was needed on the subject to further improve future projections.