Deals have been negotiated at Cop26 that will restrict global warming to under 2°C above pre-industrial levels, the US climate envoy said on Tuesday.
While the 1.5°C target has been missed, initiatives agreed to at the UN climate change summit in Glasgow are in line with temperatures hitting 1.8°C above pre-industrial levels, John Kerry said.
It is understood to be the first time commitments have been made to keep warming at below the 2°C threshold at a Cop climate conference.
Talks are now intensifying, with negotiators staying up until 3am to strike further deals in a bid to keep the rise down to 1.5°C before the conference ends on Friday.
Before the Glasgow summit, the world was heading for an unsustainable 2.7°C rise in temperatures that would cause irreversible damage, the former US Secretary of State said.
But if all the current agreements at Cop26 were added together, such as the forestry initiative along with the deforestation and methane target, “and if everybody does what they promised to do”, Mr Kerry said, “then we would be at 1.8°C".
He said it was important to look on the “bright side” of what the meeting of 190 countries had achieved. “Think about that, the notion before we came here that we could be halfway through potentially hitting that,” he said.
British Prime Minister Boris Johnson will be back in Glasgow on Wednesday to provide impetus in getting a deal over the line.
News of his return to the summit, where he welcomed world leaders last week, came as Cop26 president Alok Sharma said negotiators were making progress but there was still “a mountain to climb” over the next few days.
One forecasting organisation predicted that the world was heading towards a 2.4°C increase in global warming under the pledges made for the next decade.
Climate Action Tracker said a “massive credibility gap” of almost 1°C of warming had opened at the Cop26 talks between countries’ long-term promises and the action they were taking.
Countries were required to submit new and more ambitious 2030 targets in the run-up to Glasgow to help the world limit potentially catastrophic warming.
But the analysis says the latest targets are still inadequate – reducing the gap between what is needed and what is planned to cut emissions in 2030 by only 15 per cent to 17 per cent – and all nations must do more. The tracker team only measures the effects of short-range pledges and screens out the longer-term targets or policy promises that has seen other analysts estimate much lower increases as a result of the Glasgow announcements.
A number of announcements have been made at the Glasgow talks, such as cutting methane and halting deforestation, which the analysis says supports important action, but must go beyond existing national targets to have an effect.
Bill Hare, chief executive of Climate Analytics, one of the partners in the analysis, said: “The vast majority of 2030 actions and targets are inconsistent with net-zero goals: there’s a nearly 1°C gap between government current policies and their net-zero goals."
Prof Niklas Hohne, of NewClimate Institute, the other Climate Action Tracker partner, said: “While the wave of net-zero targets appears like remarkable news, we can’t sit back and relax.”
“All countries must urgently look at what more they can do.
“If the massive 2030 gap cannot be narrowed in Glasgow, governments must agree to come back next year, by Cop27, with new and stronger targets.
“Today’s leaders need to be held to account for this massive 2030 gap.”
But Mr Kerry said: “I think something is happening,” in reference to movement on a final text.
“I think this Cop is already different and better than any Cop I've ever been to,” he told a Bloomberg event in Glasgow.
“There is a greater sense of urgency, a greater sense of focus and a greater sense of possibilities than I've ever felt coalescing before.”
Mr Kerry, 77, was challenged over the view that the climate initiatives would be too costly, “elitist” and problematic to be accepted by people.
“Mother Nature is going to be relentless,” said the former senator. “And she's more powerful than any of us.” The world would witness “millions of people moving from places they can't live in any more” due to water shortages, such as in Africa. This would create a greater movement than the “Syrian exodus that changed the politics of Europe”.
He said big companies were turning green because they understood “their future is tied to having a stable marketplace”, with supply chains that are “not interrupted by cyclones and storms and floods”.
An important development two years after the 2015 Paris Agreement was the private sector investment in new energies, with $358 billion spent on alternative renewable energy investment.
But Mr Kerry said after Donald Trump was elected president he pulled the US out of the agreement “without science, without economic rationale, without anything except the kind of vindictive mischief”.
“We were moving in the right direction until this person appeared,” he said.
However, he suggested that technological investment and advances could now substantially help reduce emissions.
Mr Kerry warned it would be “insanity” not to check on the progress made by countries in meeting climate targets each year. “This is a long journey and now really is the test of whether we can get there,” he said.
The conference has also heard from Barack Obama, Mr Kerry’s former boss, who accused China and Russia of a “dangerous absence of urgency” in reducing harmful emissions.