A UN panel of climate scientists has issued an urgent call to reduce greenhouse gas emissions. The researchers warned that global warming could breach a key threshold within a decade.

The Intergovernmental Panel on Climate Change released a synthesis report on Monday. It's the first publication in nine years that combines the scientists' debate on the scale of global warming with what measures are needed.

Under the 2015 Paris agreement, nations around the world agreed to try to limit the rise in the average global temperature to 1.5 degrees Celsius above preindustrial levels. The latest IPCC report says the world had already warmed by 1.1 degrees in the decade to 2020.

It says humanity is unequivocally to blame for climate change, which it says has resulted in more frequent and more extreme weather events that have caused increasingly dangerous impacts on nature and people in every region of the world.

The report warns that global warming could hit the 1.5-degrees threshold in the early 2030s. It says global emissions must start decreasing by 2025 at the very least, and that reductions should reach around 43 percent by 2030 compared with 2019 levels.

The panel of scientists is calling for deep, rapid and sustained emissions reductions in all sectors. It says the choices and actions implemented in this decade will have impacts now and for thousands of years.