"It's now or never." That was the warning of UN scientists yesterday as they unveiled a plan to keep global heating to 1.5C and save the world from the worst of the climate crisis.

Last week, the Intergovernmental Panel on Climate ChangeA UN body tasked with researching climate breakdown and coming up with recommendations for states to follow. (IPCC) warned that the impacts of climate breakdown are worse than expected. Three billion lives are at risk.

If global temperature increase is kept to 1.5C, up to 14% of species face a high risk of extinction. In 2019, Australia recorded the first mammal species to have been wiped out by human-made climate change: the Bramble Cay melomysA rodent that went extinct in 2019. The whole species had been dependent on a single coral cay on the Great Barrier Reef; repeated flooding destroyed its habitat..

If all states keep their current promises, global temperatures will rise by almost 2.5C. That is why the IPCC has warned that more drastic action is needed.

If the rise is to be kept to 1.5C, emissions must peak in 2025 and shrink by 43%. The IPCC's new report lays out five steps:

Cut coal

Coal is responsible for almost one-third of global heating to date. Gas shortages have encouraged some governments to consider reintroducing it. To stay below 1.5C, we must stop burning coal. We also have to switch from all kinds of fossil fuels to renewables. 

New technology

Previously, scientists have often been cool on the idea of using big technological fixes for global heating. Plans to spray particles into the atmosphere or put reflective shields in space have received short shrift. Now the IPCC claims there is no solution to the climate crisis that does not involve removing carbon from the atmosphere. For this, we need new technology.

End subsidies

The IPCC is eager to stress that the green transition is less expensive than the alternative. A temperature rise of 2C by 2050 would reduce global GDP by 7.5%. Scrapping subsidiesMoney given by the state or another body to help keep prices low. for fossil fuels would reduce emissions by up to 10% by 2030 and save money.

Change demand

The global economy is structured around fossil fuels. The report recommends that "choice architectureAn idea taken from behavioural economics. It means nudging consumers to make particular choices, sometimes without them even realising it." can be used to shift consumer demand towards low-carbon options. That could result in a 70% reduction in emissions by 2050.

Revolutionise everything

Everything must change. The climate crisis can only be solved with massive reforms.

But some environmentalists think the IPCC has given in to fossil-fuel countries. It has put undue focus on untested technologies instead of the shift away from dirty energy.

Yes: It is easy to be fatalistic about the climate crisis, which is already wreaking havoc all around us. The new report shows there is a clear path to a better future, and it will not even cost much.

No: The IPCC can lay out recommendations but it is up to individual states to make the changes, and so far, despite the looming crisis, there has been little appetite for grand reforms.

Or... The new report probably will not be implemented. But it does show that it is now cheaper for states to cut their emissions than to keep polluting. That might be enough to persuade them to make some reforms.