AI: World likely to hit key warming threshold in 10-12 years

The world will likely breach the internationally agreed-upon climate change threshold in about a decade, and keep heating to break through a next warming limit around mid-century even with big pollution cuts, artificial intelligence predicts in a new study that's more pessimistic than previous modeling.

The study in Monday’s journal PNAS reignites a debate on whether it's still possible to limit global warming to 1.5 degrees Celsius, as called for in the 2015 Paris climate agreement, to minimize the most damaging effects of climate change. The world has already warmed 1.1 or 1.2 degrees since pre-industrial times, or the mid-19th century, scientists say.

Two climate scientists using machine learning calculated that Earth will surpass the 1.5 degree (2.7 degrees Fahrenheit) mark between 2033 and 2035. Their results fit with other, more conventional methods of predicting when Earth will break the mark, though with a bit more precision.

“There will come a time when we call the 1.5C target for maximum warming dead, beyond the shadow of a doubt,” Brown University environment institute director Kim Cobb, who wasn’t part of the study, said in an email interview. “And this paper may be the beginning of the end of the 1.5C target.”

Stanford University's Noah Diffenbaugh, a study co-author, said the world is on the brink of the 1.5-degree mark in “any realistic emissions reduction scenario.” Avoiding a 2-degree rise, he said, may depend on nations meeting zero-emissions goals by the middle of this century.

The artificial intelligence-based study found it unlikely that temperature increase could be held below 2 degrees Celsius, even with tough emissions cuts. And that’s where the AI really differs with scientists who had been forecasting using computer models that are based on...