The fires, floods and extreme weather seen around the world in recent months are just a foretaste of what can be expected if global heating takes hold, scientists say, as the world’s leading authority on climate change prepares to warn of an imminent and dire risk to the global climate system.

The Intergovernmental Panel on Climate Change (IPCC) will on Monday publish a landmark report, the most comprehensive assessment yet, less than three months before vital UN talks that will determine the future course of life on Earth.

Policymakers have already previewed the findings, finalised on Saturday night, which have been the subject of an intense two weeks of online discussion by experts around the world, and represent eight years of work by leading scientists.