PARIS: Diplomats from nearly 200 nations and top climate scientists begin a weeklong huddle in Switzerland Monday to distill nearly a decade of published science into a 20-odd-page warning about the existential danger of global warming, and what to do about it.

The UN Intergovernmental Panel on Climate Change's (IPCC) synthesis report — to be released on March 20 — will detail observed and projected changes in Earth's climate system; past and future impacts such as devastating heat waves, flooding and rising seas; and ways to halt the carbon pollution pushing Earth toward an unlivable state.