World faces a 2.8-degree warmer future by 2100 if countries continue with current 'action gap,' UN warns

The world, especially richer carbon polluting nations, remains "far behind" and is not doing nearly enough — nor even promising to do enough — to reach any of the global goals limiting future warming, a United Nations report said.

That "highly inadequate" inaction means the window is closing, but not quite shut yet, on efforts to keep future warming to just a few more tenths of a degree from now, according to Thursday's Emissions Gap report from the United Nations Environment Programme.

"Global and national climate commitments are falling pitifully short," United Nations Secretary-General Antonio Guterres said Thursday. "We are headed for a global catastrophe."

The world is weaning itself from fossil fuels too slowly, the report and experts said.

"The report confirms the utterly glacial pace of climate action, despite the looming precipice of climate tipping points we're approaching," said climate scientist Bill Hare, head of Climate Analytics, which also examines what countries are promising and doing about carbon emissions in its own analysis.

Instead of limiting warming to 1.5 or 2 C above pre-industrial levels, the global goals set by the 2015 Paris Agreement, the way the world is acting now, warming will hit 2.8 degrees by 2100, the UN report said. Countries' concrete pledges would bring that down to 2.6 degrees.

The planet has already warmed 1.1 C since pre-industrial times.

"In all likelihood we will pass by 1.5," UNEP executive director Inger Andersen told The Associated Press in an interview. She didn't say when she thinks that would happen. "We can still do it, but that means 45 per cent emissions reductions" by 2030.

World Meteorological Organization Secretary-General Petteri Taalas said the UN weather agency has calculated that there's a 50 per cent chance that the world will likely hit the 1.5 degree mark temporarily in the next five years and "in the next decade we'd be there on a more permanent basis."

"It's really about understanding that every little digit [tenth of a degree of warming] that we shave off is a lesser catastrophic outlook," Andersen said.

"We're sliding from climate crisis to climate disaster," Andersen said in a Thursday news conference.

The emissions gap is the difference between the amount of carbon pollution being spewed between now and 2030 and the lower levels needed to keep warming to 1.5 or 2 C.

Guterres said "the emissions gap is a by-product of a commitments gap. A promises gap. An action gap."

Stanford University climate scientist Rob Jackson, who chairs the independent Global Carbon Project, which tracks carbon dioxide emissions around the world but wasn't part of the UN report, said "another decade of fossil emissions at current rates and we'll zip past 1.5 C.... The way things are going, though, we'll zip past 1.5 C, past 2 C and — heaven help us — even 2.5 or 3 C."