U.N.: Humans caused 'irreversible' climate change

Deadly heatwaves, wildfires destroying U.S. towns and Greek and Siberian forests, Greenland's melting ice sheet, Germany's devastating floods: the world is dangerously close to runaway global warming - and it's "unequivocally" caused by humans.

That was the dire warning from the U.N. panel on climate change on Monday (August 9).

Greenhouse gas levels in the atmosphere are already high enough to disrupt the climate for decades, if not centuries, warned the report by the Intergovernmental Panel on Climate Change.

Unless emissions are drastically reduced, it said, average global temperatures are likely to cross the 1.5-degree Celsius threshold within 20 years.

Friederike Otto of the University of Oxford, who co-authored the IPCC report, said global warming is now "irreversible".

"And so if we stop warming at 1.5 degrees, then we will also stop many of these extremes from getting worse. And I think that while we are committed to some changes, particularly sea level rise, glacial melt, still to come for many decades, we can slow these changes down and we can stop many of the others from getting worse by urgently and drastically reducing CO2 emissions in the next decade."

Drawing on more than 14,000 scientific studies, the report gives us the most comprehensive and detailed picture yet of how climate change is altering the natural world - and what could still be ahead.

Describing the report as a "code red for humanity," U.N. Secretary-General Antonio Guterres urged an end to the use of coal and other highly polluting fossil fuels.

The 1.1 degree warming already recorded has been enough to unleash catastrophic heatwaves, floods, hurricanes and fires across the globe.

Greenpeace's UK executive director, John Sauven, said now scientists have told them what's happening, governments have to stop hitting the snooze button.

"You know, the rich countries agreed more than ten years ago to put a pot of money together to help developing countries deal with climate change. Ten years later they have still not got that money together. The trust from the developing countries and the rich world is collapsing as a result of that.... When governments know the crisis that we are facing, why are they not acting?"

The IPCC report comes just three months before a major U.N. climate conference known as COP26 in Glasgow, Scotland.

So far nation's pledges have been inadequate, but they will be under pressure to commit to more ambitious action, and substantial financing to go with it.