BERLIN (AP) — A major new United Nations (UN) report being released Monday is expected to provide a sobering reminder that time is running out if humanity wants to avoid passing a dangerous global warming threshold.

The report by hundreds of the world’s top scientists is the capstone on a series that summarises the research on global warming compiled since the Paris climate accord was agreed in 2015.

It was approved by countries at the end of a week-long meeting of the UN’s Intergovernmental Panel on Climate Change report in the Swiss town of Interlaken, meaning governments have accepted its findings as authoritative advice on which to base their actions.

At the start of the meeting UN Secretary-General Antonio Guterres warned delegates that the planet is “ nearing the point of no return ” and they risk missing the internationally agreed limit of 1.5 degrees Celsius (2.7 Fahrenheit) of global warming since pre-industrial times.

That’s because global emissions of carbon dioxide and other greenhouse gases keep increasing — mainly due to the burning of fossil fuels, deforestation and intensive agriculture — when in fact they need to decline quickly.

Governments agreed in Paris almost eight years ago to try to limit temperature rise to 1.5 C or at least keep it well below two C (3.6 F). Since then scientists have increasingly argued that any warming beyond the lower threshold would put humanity at dire risk.

Average global temperatures have already increased by 1.1 degrees Celsius (two degrees Fahrenheit) since the 19th century, but Guterres insisted last week that the 1.5 C target limit remains possible “with rapid and deep emissions reductions across all sectors of the global economy.”

Monday’s report comes after the IPCC made clear two years ago that climate change is clearly caused by human activity and refined its predictions for a range of possible scenarios depending on how much greenhouse gas continues to be released.

The following year it published a report concluding that the impacts of global warming are already being felt and nearly half the world’s population are “highly vulnerable to climate change.” Two months later it laid out what needs to be done to reduce the harm from warming that’s already inevitable and prevent a further dangerous rise in temperatures; the sharp drop in cost of solar and wind power would make that easier, it noted.

Three further special reports by the IPCC focused on the oceans, land and 1.5-degree target. The next round of reports won’t be published until the second half of this decade, when experts say it could be too late to take further measures allowing that ambitious goal to still be met.

Governments agreed at last year’s climate summit in Egypt to create a fund to help pay for the damage that a warming planet is inflicting on vulnerable countries, but failed to commit to new measures for reducing greenhouse gas emissions.

The new synthesis report published Monday will play a pivotal role when governments gather in Dubai in December for this year’s UN climate talks. The meeting will be the first to take stock of global efforts to cut emissions since the Paris deal, and hear calls from poorer nations seeking more aid.

Guterres, the UN chief, recently argued that fossil fuel companies should hand over some of their vast profits to help victims of climate change.