Developing countries at the Cop26 climate summit have called for rich nations to come forward with more financial help for vulnerable countries, saying a new draft outcome for the talks is too weak in this regard.

The draft text, published on Wednesday by the UK as president of the talks, set out the probable outcome of the Cop26 talks, including a potential requirement for countries to return to the negotiating table next year to beef up their national plans on cutting greenhouse gas emissions.

The text also set out the scientific case for limiting global temperature rises to 1.5C above pre-industrial levels, and expressed “alarm” that emissions were far higher than the levels needed to stay within safe temperature thresholds.

But poor countries said the text needed more emphasis on climate finance, to help them cut carbon and cope with the impacts of climate breakdown.

Aubrey Webson, the chair of the Alliance of Small Island States, which represents 37 of the most at-risk countries, said: “The text provides a basis for moving forward but it needs to be strengthened in key areas in order to respond to the needs of the most vulnerable, particularly on finance. We won’t get the ambition on emissions we need for 1.5C if we don’t scale up the provision of finance, and this includes the long overdue recognition of a separate and additional component for loss and damage.”

He added that the language was too weak: “‘Urging’, ‘calling’, ‘encouraging’ and ‘inviting’ is not the decisive language that this moment calls for. We have limited time left in the Cop to get this right and send a clear message to our children, and the most vulnerable communities, that we hear you and we are taking this crisis seriously.”

Other developing countries told the Guardian that clearer commitments were needed to force countries to increase their emissions cuts.

There was widespread dismay on Tuesday when a projection by Climate Action Tracker found, based on analysis of countries’ current 2030 targets, that global heating was likely to soar to 2.4C above pre-industrial levels. Scientists warn that a temperature rise on the scale would lead to devastation across the globe due to worsening heatwaves, floods, drought, storms and sea-level rise.

The draft, released before dawn in the UK on Wednesday and to be negotiated by countries over the final three days, is likely to form the basis for the main outcome at the summit, which aims to clarify and build on the Paris agreement.

It proposed that countries agree to accelerate the phasing out of coal and subsidies for fossil fuels – a potential first acknowledgement of fossil fuels’ central role in the climate crisis in a UN agreement – and called on all developed countries to at least double climate finance commitments to help those worst affected across the globe.

On the pace of cuts, it recognised the advice of the Intergovernmental Panel on Climate Change that limiting global heating to 1.5C by 2100 would require “meaningful and effective action” by all countries in this “critical decade” to achieve a 45% cut in global emissions by 2030 on the way to net zero by “around mid-century”. The draft “noted with serious concern” that based on current commitments emissions were instead on track to rise 13.7% by 2030.

Developing countries at the talks have been pushing hard for countries to be forced to revise their commitments, known as nationally determined contributions (NDCs), as soon as possible – next year, according to many.

Under the UN Framework Convention on Climate Change, the 1992 parent treaty to the Paris accord, a Cop (conference of the parties) takes place every year. But under the Paris agreement, countries have to revise their NDCs only every five years.

For the High Ambition Coalition, made up of developed and developing countries including the US, the EU, the Marshall Islands and many of the other countries most at risk from climate breakdown, waiting five years for a revision is too long. The coalition put out a statement – not yet signed by all members, but approved by the US and more than 30 others – calling for countries to have to update their NDCs every year if they were not aligned with the 1.5C goal.

Observers said the draft fell substantially short of what was needed. Jennifer Morgan, the executive director of Greenpeace International, said it was a little more than an agreement to “all cross our fingers and hope for the best”, and said stronger action was needed on finance and adaptation, including “real numbers in the hundreds of billions”.

“It’s a polite request that countries maybe, possibly, do more next year,” she said. “That’s not good enough, and the negotiators shouldn’t even think about leaving this city until they’ve agreed to a deal that meets the moment. Because most assuredly, this one does not.”

Morgan acknowledged the text called for an accelerated phase-out of coal and fossil fuel subsidies, but said it was likely “wreckers like the Saudi and Australian governments will be working to gut that part before this conference closes”.

Alden Meyer, at the thinktank e3g said: “We’ve particularly not seen the EU and US step up to push for the financial support they need to deliver for vulnerable countries to bring balance to the [Cop26] package.”

“To get what [the EU and US] say they want in Glasgow on [emissions cuts] and transparency from countries like China and others, they need to build a much stronger high ambition coalition by giving the vulnerable countries what they need and deserve on adaptation and finance and loss and damage. And for both the US and the EU, that means crossing some of their red lines.”

The UK prime minister, Boris Johnson, made a flying visit to Glasgow on Wednesday, where he warned delegates that failure to reach an effective agreement would bring an “immense” and well-deserved backlash from around the globe.

Johnson called for “a determined push to get us over the line” – and said some countries had not done enough to achieve this. Leaders not in Glasgow needed to “pick up the phone to their teams here and give them the negotiating margin, give them the space they need in which to manoeuvre and get this done”, he said.

Johnson criticised – but did not name – some countries for “conspicuously patting themselves on the back” for signing up to the Paris climate accord but doing too little at Cop.

“The world will find it absolutely incomprehensible if we fail to deliver [a good outcome]. And the backlash from people will be immense and it will be long-lasting, and frankly we will deserve their criticism and their opprobrium.”