The world's climate scientists have issued what one expert said is a "final warning" before global warming exceeds 1.5 degrees Celsius.

"The climate time-bomb is ticking," said UN Secretary-General António Guterres, at a meeting of the Intergovernmental Panel on Climate Change (IPCC), which this week released its final "synthesis report", marking six years of work by about 700 scientists. 

"Today’s IPCC report is a how-to guide to defuse the climate time-bomb," he said. "It is a survival guide for humanity."

Representatives of 195 countries negotiated an agreed text for the summary report, after assessing tens of thousands of scientific studies.

Haven't we seen a lot of IPCC reports already?

The report, known as the AR6, is a synthesis of six other reports by the IPCC — taking enormous amounts of data and simplifying it so policymakers inside and outside governments can use it.

As you can probably guess, there's not a lot of good news.

However, the scientists say there is still time to avoid the worst impacts of climate change and every bit of carbon pollution makes a difference.

The authors concluded:

• It was now "unequivocal" that climate is changing as a result of human activity, and that it is a threat to human societies and the natural world
• Climate change is already making extreme weather events more frequent — with 3.3 to 3.6 billion people living in places “highly vulnerable” to these changes
• Cuts to emissions need to be "deep, rapid and sustained" if the world is to limit warming to 1.5 degrees Celsius this decade
• If warming goes above that, adaptation will likely be too much for some communities and ecosystems to survive.

UPDATE - Thank you Underminder!