Humanity can no longer delay "ambitious" climate action, US Secretary of State Antony Blinken said Monday after the release of a landmark UN report warning of growing climate change peril.

Years in the making, the sobering report approved by 195 nations shines a harsh spotlight on governments dithering in the face of mounting evidence that climate change is an existential threat.

"This moment requires world leaders, the private sector, and individuals to act together with urgency and do everything it takes to protect our planet," Blinken said in a statement.

"We cannot delay ambitious climate action any longer," he added.

With only 1.1 degrees Celsius of warming so far, an unbroken cascade of deadly, weather disasters bulked up by climate change has swept the world this summer, from asphalt-melting heatwaves in Canada to untamable wildfires sweeping Greece and California.

"We are seeing the detrimental impacts of these events on the lives and livelihoods of people around the world," Blinken said.