The First Minister said she has not had a chance to properly absorb the new draft of the deal that could be agreed at COP26 but that, from what she has seen, a deal was “inching forward”.
She said there has been some “incremental progress”, telling Sky News: “If I was a young person looking into this summit right now I would say it’s not good enough.
“There may have been inches forward in this latest draft but there’s still time to get it even further forward and to really make the Glasgow Agreement one that lives up to the urgency of the emergency we face.”
She added: “In these final hours, the Prime Minister if necessary should come back here and drive this deal over the line.”
Asked if she was calling for Boris Johnson to come to Glasgow, Ms Sturgeon said: “If that is what it is going to take, then yes. He was here on Wednesday, I welcomed that. In his shoes, I may have stayed here for the remainder of the summit, but come back. Every shoulder to the wheel.
“I’m not in the negotiating room. That can feel frustrating sometimes. But get there, and make sure that no stone is left unturned in getting this agreement to where it needs to be.”
She said Boris Johnson should return to COP26 to push people on to a path “where we avoid climate catastrophe.”
When asked what her message to the Prime Minister would be, she said: “My message to the Prime Minister is come back here.
"Use your position as president of this COP to really drive progress and push people as far as we can get them.
“Because every inch forward that this text takes is of course another inch towards getting the world on to a path where we avoid climate catastrophe, and nothing, literally nothing, is more important than that.”
She added: “The reason I’m singling out Boris Johnson is not just because we’re in the UK – well, it is actually because we’re in the UK, because the UK is the COP presidency, and that puts a particular onus on the shoulders of the UK Government.”
The First Minister also said she does not want the Cambo oil field to be "given the green light", and "at the very least" it should undergo "the most rigorous climate assessment"
Asked if Friday would be the last day of COP26, she added: “I wouldn’t bet lots of money on that. I hope we see progress today.
“I certainly hope that finishing at six o’clock tonight, which is the plan, would be possible.
“Equally, I would not be surprised to know that it was going into tomorrow.”
It is hoped that an agreement at COP26 will curb fossil fuel use and limit global temperature rises to 1.5C.
A new draft of an agreement was produced on Friday morning and contained strengthened language on getting countries to “revisit and strengthen the 2030 targets” in their national action plans by the end of 2022 to align with global goals to limit temperature rises to “well below” 2C and try to limit them to 1.5C.
There is also more on finance for poorer countries to adapt with climate change and a request for all nations to strengthen their plans for cutting emissions up to 2030 by the end of next year.
The first draft of the “cover decision” for the overarching agreement at the summit called for countries “to accelerate the phasing-out of coal and subsidies for fossil fuels”.
In a new draft produced on Friday morning, that has changed to calling on countries to accelerate the shift to clean energy systems, “including by rapidly scaling up clean power generation and accelerating the phaseout of unabated coal power and of inefficient subsidies for fossil fuels”.
The inclusion of a direct reference to coal and fossil fuel subsidies was thought to be a first for a UN decision document of this type but had been expected to get fierce pushback from some countries and may not make it into the final text.
Talks went on through the night and look set to overrun from their finish time of Friday evening as negotiators come under pressure to resolve issues around finance for poor countries, fossil fuels, the efforts of countries to cut emissions in the 2020s and rules on carbon markets and transparency.
There is debate over the language on getting countries to “revisit and strengthen the 2030 targets” in their national action plans by the end of 2022 to align with the Paris temperature goals.
In the Paris Agreement in 2015, countries committed to limit temperature rises to “well below” 2C and try to limit them to 1.5C – beyond which the worst impacts of climate change will be felt.
Scientists have warned that keeping temperature rises to 1.5C – beyond which the worst impacts of climate change will be felt – requires global emissions to be cut by 45% by 2030, and to zero overall by mid-century.
But current action plans known as nationally determined contributions for emissions cuts up to 2030 leave the world well off track to meet the goal, and could see warming of 2.4C over the long term.
Therefore, countries are under pressure to rapidly increase their ambition for emission cuts in the 2020s to stop the 1.5C goal slipping out of reach.
The new version of the text “requests” countries to revisit and strengthen their plans for 2030 within the next year, compared to the previous version which “urges” them to do so.
Michael Jacobs, former climate adviser to Gordon Brown and veteran of Cop talks, and Peter Betts, former lead UN climate negotiator for the EU, and UK, both suggested the new wording was stronger, but the World Resources Institute (WRI) think tank, said it was a weakening of the language.
Cop president Alok Sharma has been clear there are no efforts to renegotiate the Paris Agreement – which means that both the “well below” 2C and 1.5C targets are still both included in the Paris goal – though he has also said a key aim of Glasgow is about keeping the 1.5C goal within reach.
Addressing the climate summit on Friday afternoon, Mr Sharma said: “This is our collective moment in history, this is our chance to forge a cleaner, healthier, more prosperous world.
“This is our time to deliver on the high ambition set by our leaders at the start of this summit.
“We must rise to the occasion.”
In the wake of the new draft, shadow business secretary Ed Miliband warned: “It’s clear that the aim of this summit to keep 1.5 alive is in mortal peril.
“There has been some welcome progress on strengthening the pathway out of Glasgow in the new draft.
“But there is still too much ambiguity about the responsibility of all countries to align their targets with 1.5C and important language on keeping fossil fuels in the ground has been watered down.
He said: “It is absolutely vital that there is no backsliding, no fudges and no bending over backwards for the big emitters over the next crucial hours.”
Greenpeace International executive director Jennifer Morgan said of the text: “It could be better, it should be better, and we have one day left to make it a lot, lot better.”
Providing finance for developing countries to develop cleanly, adapt to the impacts of climate change and address the loss and damage to people, livelihoods, land and infrastructure already being hit by increasing weather extremes and rising seas is also key to securing a deal in Glasgow.
Helen Mountford, WRI vice-president for climate and economics, said: “Overall, on balance this is definitely a stronger and more balanced text than we had a few days ago.”
She said sections on adaptation finance and loss and damage appear stronger but the reference to “inefficient” fossil fuel subsidies “does weaken that a little”.
She said a gap remains on the pledge from developed nations to mobilise one billion US dollars a year from 2020, with no reference to making up the current shortfall.
There is now a date – missing from the first draft – for when developed countries should double the provision of finance to help developing countries adapt to climate change – by 2025.