Leaders of the Group of 20 major economies agreed on a final statement on Sunday that urges “meaningful and effective” action to limit global warming but offers few concrete commitments.

The statement represented “half-measures” rather than “concrete urgent action”, one non-governmental organisation said.

According to the final communiquè, the G20 leaders agreed to end public financing for coal-fired power generation abroad but set no target for phasing out coal domestically — a clear nod to coal-dependent countries, including China and India, and a blow to Britain which had hoped for more solid commitments ahead of the Glasgow meeting.

The final statement promises to phase out coal power “as soon as possible” but mentions no date. This replaces a goal set in a previous draft of the final statement to achieve this by the end of the 2030s, showing how strong the pushback from some coal-dependent countries is.

The result of days of tough negotiation among diplomats left huge work to be done at the broader UN climate summit in Glasgow, Scotland, to where most of the G20 leaders will fly directly from Rome, and disappointed climate activists.

The stakes are huge — among them the very survival of low-lying countries, the impact on economic livelihoods the world over and the future stability of the global financial system.

UN Secretary-General Antonio Guterres, who warned on Friday that the world was rushing headlong towards climate disaster, said the Rome summit neither fulfilled his hopes nor buried them.

“While I welcome theG20’s recommitment to global solutions, I leave Rome with my hopes unfulfilled — but at least they are not buried,” he tweeted. “Onwards to COP26 in Glasgow to keep the goal of 1.5 degrees alive and to implement promises on finance and adaptation for people and planet.”

The G20 bloc, which includes Brazil, China, India, Germany and the US, accounts for an estimated 80 per cent of global greenhouse gas emissions.

“This was a moment for the G20 to act with the responsibility they have as the biggest emitters, yet we only see half-measures rather than concrete urgent action,” said Friederike Roder, vice-president of sustainable development advocacy group Global Citizen.

The final document says the current national plans on how to curb emissions will have to be strengthened “if necessary” and makes no specific reference to 2050 as a date to achieve net zero carbon emissions.

“We recognise that the impacts of climate change at 1.5 degrees Celsius are much lower than at 2°C. Keeping 1.5°C within reach will require meaningful and effective actions and commitment by all countries,” the communiquè said.

The 1.5°C threshold is what UN experts say must be met to avoid a dramatic acceleration of extreme climate events like droughts, storms and floods, and to reach it they recommend net zero emissions should be achieved by 2050.

The leaders only recognised “the key relevance” of halting net emissions “by or around mid-century”, a phrase that removed the 2050 date seen in previous versions of the final statement so as to make the target less specific.

China, the world’s biggest CO2 emitter, has set a target date of 2060, and other large polluters such as India and Russia have not committed to the 2050 target date, either.

UN experts say that even if current national plans are fully implemented, the world is headed for global warming of 2.7°C, with catastrophic consequences.

The G20 set no date, either, for phasing out fossil fuel subsidies, saying it would aim to do so “over the medium term”.

On methane, which has a more potent but less lasting impact than carbon dioxide on global warming, the grouping watered down its wording from a previous draft that had pledged to “strive to reduce our collective methane emissions significantly”.

The final statement merely recognises that reducing methane emissions is “one of the quickest, most feasible and most cost-effective ways to limit climate change”.

G20 sources said the negotiations were tough over the so-called “climate financing”, which refers to a 2009 pledge by rich nations to provide $100 billion per year by 2020 to help developing countries tackle climate change.

They have failed to meet the pledge, generating mistrust and a reluctance among some developing nations to accelerate their emission reductions.

“We recall and reaffirm the commitment made by developed countries, to the goal of mobilising jointly $100 billion per year by 2020 and annually through 2025 to address the needs of developing countries,” the G20 statement says.

World leaders will kick-start the COP26 on Monday with two days of speeches that could include some new emissions-cutting pledges, before technical negotiators lock horns over the rules of the 2015 Paris climate accord.