All major economies must do the “maximum” they can to avert the climate crisis, UN secretary general Antonio Guterres has warned.

Mr Guterres said a new report from the UN Environment Programme (UNEP), which shows the latest plans and pledges by countries to curb climate emissions by 2030 put the world on track for a “catastrophic” 2.7C of warming, was a “thundering wake up call”.

Unep executive director, Inger Andersen, said seven times the level of current ambition is needed to bring emissions down to a level by 2030 that puts the world on track to limit warming to 1.5C – the highest level at which the worst impacts of climate change will not be felt.

And Mr Guterres warned a “huge effort” was needed to make sure the world reaches net-zero emissions in 2050 globally – required to hit the 1.5C target – but also to ensure a meaningful reduction of emissions in the next decade.

He warned: “If there is no meaningful reduction of emissions in the next decade, we will have lost forever the possibility of reaching 1.5C.”

He described it as a moment of truth, and said he would be joining the G20 biggest economies as they meet in Rome this weekend ahead of the crunch Cop26 climate talks in Glasgow which begin on Sunday.

“I will be strongly appealing for all of them to do their maximum,” he said.

He acknowledged the international climate principle of “common but differentiated responsibilities” with countries doing what they can according to their national capabilities.

This, he said “means that the leadership must come from developed countries but the level of emissions of the emerging economies is such that we also need the emerging economies to go the extra mile”.

UN climate change report
UN secretary general Antonio Guteeres has demanded the maximum effort in a bid to avert climate change (Danny Lawson/PA)

“Only if everybody does the maximum, it will be possible to get there.”

China, the world’s biggest polluter, is among the G20 nations yet to submit new national plans under the UN climate process for cutting emissions up to 2030.

Mr Guterres urged China to deliver on its pledges to reach net zero before 2060 and peak emissions before 2030 as far in advance of those dates as possible.

Ms Andersen said that, five days before Cop26, climate action was still inadequate.

She said the new and updated action plans by countries only took emissions down 7.5% beyond what had already been committed, compared to the need to cut emissions by 55% to meet the 1.5C target.

“This is a yawning gap that we must close in eight years: eight years in which we must increase ambition, make new plans, put in place new policy, implement them and ultimately deliver the cuts,” she said.

She said it was time to “get it done”, through stronger commitments, policies and action, adding: “We need to go firm, we need to go fast, and we need to start doing it now.”