Alok Sharma, the former UK cabinet minister who presided over the Cop26 climate summit in Glasgow last year, has warned delegates at Cop27 that the possibility of limiting global heating to no more than 1.5C may be at risk. “We’ll either leave Egypt having kept 1.5C alive, or this will be the Cop where we lose 1.5C,” Sharma said at the opening on Monday of the high-level ministerial roundtable on pre-2030 ambition. He said sticking to the global goal of limiting temperature rises to 1.5C above pre-industrial levels had to be a “red line” for all countries at Cop27, and insisted there could be no “backsliding” from it. He reminded the gathered ministers of what was achieved last year, in very different geopolitical circumstances than the current talks. “At Cop26 we did resolve collectively to pursue efforts to limit the temperature increase to 1.5C,” he said. “I have always said what we agreed in Glasgow and Paris has to be the baseline of our ambition. We’ve got to stick to that commitment. We cannot allow any backsliding.” But he warned: “We are already at 1.1C of global warming, and I know I don’t have to remind all of you the impact of that around the world. Even at 1.5C we are still going to have devastating outcomes for many millions … 1.5C needs to be a red line. And this cannot be the Cop where we lose 1.5C. “We’ve got to fight for this, and every fraction of a degree absolutely makes a difference. It’s the difference … between a tolerable existence and an impossible future.” He said countries needed to set out clearly how they would cut greenhouse gas emissions in line with the 1.5C target. “We’ve got a G20 leaders’ meeting going on right now,” he said, referring to the summit in Bali. “They need to reaffirm their commitment to Paris and to Glasgow.” He called on countries that had not yet submitted revised national plans on emissions, called nationally determined contributions, to draw them up urgently. He also called for a faster phasing-out of coal and of fossil fuel subsidies, and for technical issues in the Cop work programme to be resolved. He added that keeping the 1.5C goal alive was fundamental to the other key issues of Cop27, including climate finance and the struggles over loss and damage. “The reality is [that] without progress on [cutting emissions] we are going to beyond our ability to adapt, and of course I want to see progress made on loss and damage here but unless we stick to [1.5C] all of that is going to be a lot more difficult.” He concluded starkly: “You need to work out how you want future generations to look upon this Cop and each of us individually as countries. It’s really up to us to decide. I hope we will decide to keep 1.5C alive.” The warning comes amid anxiety that some countries may be trying to get the wording around 1.5C weakened. Simon Evans of Carbon Brief reported on Monday that some countries had been pushing to move from the 1.5C focus agreed at Cop26 to the higher 2C limit agreed in the 2016 Paris accord.