U.S. climate envoy John Kerry and his Chinese counterpart Xie Zhenhua unveiled an outline late on Wednesday in which China, the biggest producer and user of coal, promised to accelerate its transition from the dirtiest fossil fuel.

The deal by two global powers, which have been divided by a raft of diplomatic disputes on other issues, sends a powerful message to delegations at the COP26, including producers of the fossil fuels that are the main cause of manmade global warming.

“Together we set out our support for a successful COP26, including certain elements which will promote ambition,” Kerry told a news conference. “Every step matters right now, and we have a long journey ahead of us.”

Speaking through an interpreter, Xie told reporters that China would strengthen its emissions-cutting targets. “Both sides will work jointly and with other parties to ensure a successful COP26 and to facilitate an outcome that is both ambitious and balanced,” Xie said.

The joint declaration said China, home to half the world’s coal-fired plants, would begin phasing out its coal consumption from 2026-30 and also cut its emissions of methane.

Observers at the climate talks in Glasgow had been worried before the announcement that Chinese President Xi Jinping was not attending and Beijing had made no substantial new pledges to achieve carbon neutrality before 2060.

China’s climate plan had also not addressed its methane emissions, linked largely to its sprawling coal industry.

The United States has set a goal to decarbonise its economy by 2050, although President Joe Biden has been struggling to pass crucial legislation to do so through a politically divided Congress.

‘BREAKTHROUGH’

“It’s really encouraging to see that those countries that were at odds in so many areas have found common ground on what is the biggest challenge humanity faces today,” EU climate policy chief Frans Timmermans told Reuters.

“It certainly helps us here at COP to come to an agreement.”

Durwood Zaelke, president of the Institute for Governance and Sustainable Development, said it was “the breakthrough that should set the tone for wrapping an ambitious COP“.

A first draft of the COP26 deal released on Wednesday received a mixed response from climate activists and experts.

It implicitly acknowledged that current pledges to reduce greenhouse gas emissions up to 2030 were insufficient to avert climate catastrophe, asking countries to “revisit and strengthen” their targets next year.

In a first for a U.N. climate conference, it also called for the huge state subsidies that support the oil, coal and gas industries to be phased out.

The final two days of negotiations are likely to be fierce.

The conference host, Britain, says the goal is to “keep alive” hopes of capping global temperatures at 1.5 degrees Celsius (2.7 Fahrenheit) above pre-industrial levels, still far out of reach under current national pledges to cut emissions.

The landmark 2015 Paris Agreement legally bound its signatories collectively to keep the rise “well below” 2.0 degrees Celsius (3.6 Fahrenheit) this century, and to “pursue efforts” to keep it below 1.5C.

Since then, scientific evidence has grown that crossing the 1.5C threshold would unleash significantly worse sea level rises, floods, droughts, wildfires and storms than those already occurring, with irreversible consequences.

‘GOD’S JUDGMENT‘

On Tuesday, the Climate Action Tracker research group said all national pledges so far to cut greenhouse gases by 2030 would, if fulfilled, allow the Earth’s temperature to rise 2.4C by 2100.

Greenpeace dismissed the draft as an inadequate response to the climate crisis, calling it “a polite request that countries maybe, possibly, do more next year”.

The first draft dodges demands by poorer countries for assurances that rich nations provide far more money to help them curb their emissions and cope with the consequences of rising temperatures – one of the most contentious issues.

Poor countries are seeking tougher rules for future funding, after rich nations failed to meet a 2009 pledge to provide $100 billion a year in climate finance by 2020, and now expect to deliver it three years late.

The final text from the COP26 meeting will not be legally binding, but will carry the political weight of the nearly 200 countries that signed the Paris accord.

Pope Francis said in a letter to Scotland’s Catholics that he regretted not having been able to attend COP26‘s opening.

“Time is running out,” he said. “This occasion must not be wasted, lest we have to face God’s judgment for our failure to be faithful stewards of the world he has entrusted to our care.”