“Humanity is on thin ice — and that ice is melting fast,” United Nations Secretary-General Antonio Guterres said when the IPCC Synthesis Report was published on 20 March. “Our world needs climate action on all fronts — everything, everywhere, all at once.”

This is likely the last warning the IPCC scientists will be able to make about the 1.5°C mark because their next set of reports may well come after Earth has either passed the mark or is locked into exceeding it soon, several scientists, including report authors, told The Associated Press .

After 1.5°C degrees “the risks are starting to pile on,” said report co-author Francis X. Johnson, climate, land and policy scientist at SEI and member of the extended writing team for the Synthesis Report.

“The window is closing if emissions are not reduced as quickly as possible,” Johnson said. “Scientists are rather alarmed.”

The report mentions “tipping points” around that temperature  of species extinction, including coral reefs , irreversible melting of ice sheets  and sea level rise  of several meters (several yards).

To stay under the warming limit set in Paris the world needs to cut 60% of its greenhouse gas emissions by 2035, compared with 2019, adding a new target not previously mentioned in six previous reports issued since 2018.