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New study finds Earth is halfway towards a climate 'tipping point'

A new study from researchers around the globe has found that Earth is halfway towards a "tipping point" which would introduce a "hothouse" climate triggering sea rises of between 10 and 60 metres.

The study, titled Trajectories of the Earth System in the Anthropocene, was published in the international journal Proceedings of the National Academy of Sciences of the United States of America (PNAS).

It examined feedback processes within the Earth's climate systems, which could self-trigger the release of carbon back into the atmosphere after being stored for long periods of time.

Lead researcher Professor Will Steffen said if human emissions pushed up average global temperatures by just 2C, that could trigger these feedback processes, leading to further temperature rise.

Global average temperatures are currently about 1C above pre-industrial temperatures - half way towards the tipping point - and it is rising by about 0.17C each decade.

"Even if the Paris Accord [Agreement] target of a 1.5C to 2C rise in temperature is met, we cannot exclude the risk that a cascade of feedbacks could push the Earth system irreversibly onto a 'hothouse Earth' pathway," the study reads.

"As yet [these initiatives] are not enough to meet the Paris target."

Professor Steffen said there needs to be international cooperation and that the transition towards an emission-free world economy must be prioritised.

"Collective human action is required to steer the Earth system away from a potential threshold and stabilise it in a habitable interglacial-like state.

"The impacts of a hothouse earth pathway on human societies would likely be massive, sometimes abrupt, and undoubtedly disruptive."

AUT Head of Environment Sciences Len Gillman, speaking this morning to TVNZ 1's Breakfast, said the findings show "a devastating situation" could be on the horizon.

He said the temperature targets set in the Paris Agreement now need to be adjusted - "We've got to perhaps do more than what we were planning to do - more quickly.

"It's saying that even if we meet the Paris Agreement ... then we still could be in deep trouble," Professor Gillman said.

"We're looking at 30-60 years at the point when we might be hitting the first of those tipping points - things like the loss of sea ice.

Asked what people can do to help, he said everyone can help to reduce greenhouse gas emissions.

"Personally - people could stop driving to work - it's actually totally possible for most people to cycle to work and get there quicker."

Professor Len Gillman says the study found a sea level rise of between 10-60 metres could be on the cards unless drastic action is taken. Source: Breakfast