MADRID: UN Secretary-General Antonio Guterres said Sunday that the world’s efforts to stop climate change have been “utterly inadequate” so far and there is a danger global warming could pass the ``point of no return.’’

Speaking before the start Monday of a two-week international climate conference in Madrid, the UN chief said the impact of rising temperatures — including more extreme weather — is already being felt around the world, with dramatic consequences for humans and other species.

He noted that the world has the scientific knowledge and the technical means to limit global warming, but “what is lacking is political will.”

“The point of no return is no longer over the horizon,” Guterres told reporters in the Spanish capital. “It is in sight and hurtling toward us.”

Delegates from almost 200 countries will try to put the finishing touches on the rules governing the 2015 Paris climate accord at the Dec. 2-13 meeting, including how to create functioning international emissions trading systems and compensate poor countries for losses they suffer from rising sea levels and other consequences of climate change.

Guterres cited mounting scientific evidence for the impact that man-made emissions of greenhouse gases are already having on the planet, including record temperatures and melting polar ice.

But he insisted that his message was “one of hope, not of despair. Our war against nature must stop and we know that that is possible.”

Countries agreed in Paris four years ago to limit global warming to well below 2 degrees Celsius (3.6 Fahrenheit), ideally 1.5C (2.7F) by the end of the century compared with pre-industrial times. Already, average temperatures have increased by about 1C, leaving little room for the more ambitious target to be met.

Guterres said growing demands from citizens, particularly young people, have shown there is widespread desire for climate action.