The world needs “immediate and deep” emissions reductions if it is to limit potentially catastrophic global warming to 1.5°C, but the low-carbon technologies that need to be deployed are already available, including nuclear.

To stay under 1.5°C according to the Intergovernmental Panel on Climate Change (IPCC) report, means that carbon emissions from everything that we do, buy, use or eat must peak by 2025, and tumble rapidly after that, reaching net-zero by the middle of this century.

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.

The expansive report – which runs to more than 3,600 pages – warns that any further delay in global action to slow climate change and adapt to its impacts “will miss a brief and rapidly closing window of opportunity to secure a liveable and sustainable future for all”.