A UN Environment Programme annual report said that keeping global warming below 1.5°C is no longer feasible and that the priority is to keep any overshoot as small and brief as possible. It said this would require steep cuts in coal, oil and gas use as well as large-scale removal of greenhouse gases from the atmosphere, including through reforestation or carbon-storage technology.

The report said the United States' withdrawal from the Paris Agreement increases projected warming. Even if all other countries fully carry out their climate plans, global temperature would be 2.6°C above the mid-19th-century level by the end of the century. Rapid growth in renewable energy, electric vehicles and batteries offers opportunities, but has not yet reduced fossil-fuel use enough, according to the report.