Employees collapsing from scorching heat amid 'global boiling': UN

Guterres noted that while there has been some progress towards climate action, these are not happening fast enough.

"Leaders – and particularly G20 countries responsible for 80% of global emissions – must step up for climate action and climate justice," he said.

Among other measures, Guterres called for "ambitious" new national emissions reduction targets from member of the G20.

Developed countries are also urged to reach net zero emissions as close as possible to 2040, while emerging economies as close as possible to 2050.

The UN secretary general also called for action from leaders beyond governments.