Worst case eased for climate

THE UN’S worst case scenario for how much the earth’s temperature willincrease by has been reduced by 0.6C.

A prediction of 1.5-4.5C warming if atmospheric levels of carbon dioxide are doubled has been the international standard since 1979.

But a new study authored by a 25-strong team of international climate scientists over four years suggests it is “extremely unlikely” that warming would stay below 2C above pre-industrial levels, and puts minimum warming at 2.3C. The likelihood of staying between 1.5C and 2C is 5 per cent.

The study maintains the top temperature at 4.5C, but says some recent predictions that warming above that will be reached are also “unlikely”, with a 6-18 per cent chance. A less cautious analysis by the experts puts likely warming at an even narrower range of 2.6–3.9C.

A doubling of carbon dioxide in the atmosphere is predicted to happen within the next 60-80 years if current emissions are maintained.

That timeline will be extended by climate action such as that agreed in the Paris Accord.

“One of the most worrying aspects of climate change is that it is very much a roll of the dice,” said Zeke Hausfather, one of the co-authors of the study published in Review of Geophysics.

 Sharks have disappeared from nearly a fifth of the world’s reefs, leaving them “functionally extinct”, according to a new study. Researchers placed more than 15,000 cameras in 371 reefs off the coast of 58 countries to track the sharks over three years, in the most in-depth study of the global population.