There is a greater sense of urgency and focus at Cop26 than ever before, US climate envoy John Kerry has said – but warned it was “job not done”.

The special presidential envoy on climate, appointed by US President Joe Biden, hailed the flurry of announcements on phasing out coal, cutting methane emissions, delivering green finance and protecting forests in the first days of the climate summit in Glasgow.

Mr Kerry said he had been surprised by International Energy Agency (IEA) boss Fatih Birol’s suggestion that, if implemented, all the pledges countries have made to date could limit global warming to 1.8C – but it had been confirmed by other modelling.

That would put it close to the 1.5C warming limit countries have promised to try to meet, to avoid the worst impacts of storms, droughts, floods, damage to crops, health and wildlife and rising seas that higher temperatures will bring.

Mr Kerry, a veteran of the UN climate negotiation process, said of the Cop26 talks: “The bottom line is, I personally have been to many Cops and I will tell you there is a greater sense of urgency at this Cop, there’s a greater sense of focus.

“And I have never, in the first days of any of the Cops I’ve been to, counted as many initiatives, as much real money being put on the table, even as there are some question marks legitimately about some of the money.”

But Mr Kerry said there needed to be a deal out of the talks that was a “strong statement and implementable”, warning: “The words don’t mean enough unless they are implemented.”

And he warned: “Let me emphasis as strongly as I can: job not done, job not done the day this ends.

“The first part of the job, of codifying the urgency will hopefully be done, but that’s just the beginning.

“This is a 10-year, decade-long race if we are being guided as I am, as I think President Biden is, as most of us are by the science.”

In order to meet the 1.5C target, scientists have warned the world must cut carbon emissions by 45% by 2030 – but national plans submitted under the UN process by countries for the action they will take leave the world miles off track to keep to the safe limit.

So there is pressure on countries to address how to close the gap between ambition and action required up to 2030, as part of the negotiated text that it is hoped will be secured by the end of the two weeks of talks – with some climate-vulnerable nations calling for annual assessments to drive progress.

Quizzed on how often he wanted nations to revisit their climate action up to 2030, Mr Kerry said the time frame would have to be agreed by countries.

But he said: “Our goal is to have the most frequent possible measurement of what countries are achieving.

“If you’re going to be real about this, and we want to be and we are, you can’t push out into the long-term future an assessment of where you are, it just doesn’t make sense.

“The evidence is mounting faster, the science is coming back faster, we’re all moving – I think – faster, and we need to know what the interaction of all that is, we need to understand where that leaves us.”

He said it would be “negligent” to come out of Cop26 with too long a horizon for revisiting action, and warned it “behoves us, in order to convey to people the seriousness of purpose, to revisit this as much as we can”.

He said that by the end of the conference, they would not have all countries at a sufficient level of action, but there could be a “critical mass” of countries moving in a way that keeps 1.5C alive.

“We all need to be pressing our ambition going forward,” he said, adding that it was a tough task, but one that was doable, to make Glasgow a success.