An international team of scientists has published a study in Proceedings of the National Academy of Sciences (PNAS) showing that even if the carbon emission reductions called for in the Paris Agreement are met, there is a risk of Earth entering what the scientists call “Hothouse Earth” conditions.

A “Hothouse Earth” climate will in the long term stabilize at a global average of 4-5°C higher than pre-industrial temperatures with sea level 10-60 m higher than today, the paper says.

The authors conclude it is now urgent to greatly accelerate the transition towards an emission-free world economy.

"Human emissions of greenhouse gas are not the sole determinant of temperature on Earth. Our study suggests that human-induced global warming of 2°C may trigger other Earth system processes, often called “feedbacks”, that can drive further warming - even if we stop emitting greenhouse gases," says lead author Will Steffen from the Australian National University and Stockholm Resilience Centre.

"Avoiding this scenario requires a redirection of human actions from exploitation to stewardship of the Earth system.”

Currently, global average temperatures are just over 1°C above pre-industrial and rising at 0.17°C per decade.