Alok Sharma has told the formal opening session of the crunch climate summit in Glasgow that it is the last, best chance to keep temperature limits to 1.5C.
As he assumed the role of COP26 president, Sharma said he believed the conference could launch a decade of ever-increasing ambition and action.
However, he warned countries gathered for the talks, which aim to prevent dangerous temperature rises, that they would succeed or fail as one.
Sharma told delegates: “The rapidly-changing climate is sounding an alarm to the world to step up on adaptation, to address loss and damage, and to act now to keep 1.5 alive.
“We know that this COP, COP26, is our last, best hope to keep 1.5C in reach.”
He warned the window to keeping temperatures to 1.5C – beyond which scientists warn the most dangerous impacts of climate change, rising seas and extreme weather will be felt – was closing.
Pointing to devastating impacts around the world, including droughts, heatwaves, hurricanes and floods, he said: “We know our shared planet is changing for the worse and we can only address that together through this international system.”
Sharma told countries that six years ago at the Paris summit, they had agreed to pursue efforts to limit temperatures to 1.5C under the Paris Agreement.
He said he believed that the conference could resolve the outstanding issues that need to be agreed to implement the Paris deal, “move the negotiations forward and launch a decade of ever-increasing ambition and action”.
“Together we can seize the enormous opportunities for green growth for good, green jobs for cheaper, cleaner power.
“We need to hit the ground running to develop the solutions that we need. And that work starts today – and we succeed or fail as one.”
Concluding his speech, Sharma said: “If we act now, and we act together, we can protect our precious planet.
“So, let’s come together in these two weeks and ensure that where Paris promised, Glasgow delivers.”
At the formal opening of the Cop26 climate summit in Glasgow, Patricia Espinosa, UN climate chief, told delegates that the world stood at a “pivotal point in history”.
“Humanity faces stark but clear choices. We either choose to achieve rapid and large-scale reductions of limiting emissions to keep the goal of limiting global warming to 1.5C or we accept that humanity faces a bleak future on this planet.”
She said people can either choose to boost adaptation efforts to deal with weather disasters and build future resilience, or “accept that more people will die, more families will suffer and more economic harm will follow”.
The conference officially starts on Sunday before world leaders attend the summit on Monday for an official opening ceremony which will hear from Prime Minister Boris Johnson, the Prince of Wales and Sir David Attenborough, as well as UN secretary general Antonio Guterres.