The authors of the landmark report by the UN Intergovernmental Panel on Climate Change (IPCC) released on Monday say urgent and unprecedented changes are needed to reach the target, which they say is affordable and feasible although it lies at the most ambitious end of the Paris agreementpledge to keep temperatures between 1.5C and 2C.

The half-degree difference could also prevent corals from being completely eradicated and ease pressure on the Arctic, according to the 1.5C study, which was launched after approval at a final plenary of all 195 countries in Incheon in South Korea that saw delegates hugging one another, with some in tears…

What difference would restricting warming to 1.5C make?

A key finding of the new IPCC report is the dramatic difference that restricting warming to 1.5C above pre industrial levels would have on the global environment.

The scientists found:

• By 2100, global sea level rise would be 10cm lower with global warming of 1.5C compared with 2C.

• Extreme heatwaves will be experienced by 14% of the world's population at least once every five years at 1.5C. But that figure rises to more than a third of the planet if temperatures rise to 2C

• Arctic sea ice would remain during most summers if warming is kept to 1.5C. But at 2C, ice free summers are 10 times more likely, leading to greater habitat losses for polar bears, whales, seals and sea birds.

• If warming is kept to 1.5C, coral reefs will still decline by 70-90% but if temperatures rise to 2C virtually all of the world's reefs would be lost