The world can still hope to stave off the worst ravages of climate breakdown but only through a “now or never” dash to a low-carbon economy and society, scientists have said in what is in effect a final warning for governments on the climate.

Greenhouse gas emissions must peak by 2025, and can be nearly halved this decade, according to the Intergovernmental Panel on Climate Change (IPCC), to give the world a chance of limiting future heating to 1.5C above pre-industrial levels.

The final cost of doing so will be minimal, amounting to just a few percent of global GDP by mid-century, though it will require a massive effort by governments, businesses and individuals.

But the chances were narrow and the world was failing to make the changes needed, the body of the world’s leading climate scientists warned. Temperatures will soar to more than 3C, with catastrophic consequences, unless policies and actions are urgently strengthened.

Guest post from The Guardian