"If all that emerges from COP26 is more hot air, then we have absolutely no chance of keeping our planet cool," Johnson told the virtual Petersberg Climate Dialogue summit on Thursday.

"It must be a summit of agreement, of action, of deeds, not words. For that to happen, over the next six months, we must be relentless in our ambition and determination, laying the foundations on which success will be built," he said.

Britain wants the COP26 summit in Glasgow, Scotland, in November to an in-person meeting. It had originally been due to be held in 2020, but had to be postponed due to the COVID-19 pandemic.

Johnson said he would be pushing leaders at the G7 summit in June to make firm climate commitments.

"I'll be seeking commitments from the G7 members to use their voices and their votes, wherever and whenever possible to support the transition to net zero, kickstart a green industrial revolution, and build economies that withstand whatever our changing climate throws at us," Johnson said.

"And I also hope to secure a substantial pile of cash with which to help all countries to do that. We simply must meet our existing commitments on climate finance, that long overdue $US100 billion a year target, and then we must go further still."

Australian Associated Press