Failure to act on climate change will be a “betrayal of young people around the world” and risks life on earth becoming “unrecognisable”, Scotland’s First Minister has told world leaders.

Nicola Sturgeon used a speech ahead of the global Cop26 summit to challenge those countries which have the highest emissions levels – such as China, Russia, the US and India –  to do more to tackle the climate emergency.

Speaking at an event at Strathclyde University in Glasgow ahead of the giant UN conference getting under way on Sunday, Ms Sturgeon warned that even keeping temperature rises to 1.5C would not prevent all the damaging impacts of climate change.

Limiting temperature rises to as close to 1.5C as possible was one of the key agreements from the Paris climate summit in 2015, with the upcoming Cop26 event in Glasgow being seen as a chance to step up efforts towards achieving that.

The First Minister continued: “The hard fact is this: ‘Keeping 1.5 alive’ – which has become the strapline almost for Cop26 – is vital. It mustn’t become a face-saving slogan. It must be real.

“And both in the run-up to and at Cop itself, there needs to be a significant uplift in ambition from the world’s biggest-emitting countries to make that real.

“And each and every country gathered round the negotiating table also knows the action that is needed to prevent it. So there is not excuse for failing to act.”

She issued the challenge as she made clear that “justice and fairness will be central to Scotland’s whole approach to Cop26”.

Ms Sturgeon went on to pledge to “work to ensure that leaders of my generation understand that failure to act now would be a betrayal of young people around the world”.

She told the audience, which included students and young people’s representatives, that their anger about the climate change issue was “entirely justified”.

The First Minister said that “challenging interactions” with young activists had helped push her to “go much further and faster” in tackling the problem.

And she added a “fundamental test of success for Cop26” would be if more world leaders could look young people in the eye “and say that we are doing enough”.

The First Minister also insisted developed nations must meet their promise to provided poorer countries with cash to help them tackle climate change.

She noted that at a summit in Copenhagen 12 years ago, “developed countries promised 100 billion dollars of climate finance every year from 2020”.

Ms Sturgeon said: “Here in Glasgow, that promise must be delivered.”

She insisted: “Delivering on a 12-year-old promise is quite simply the right thing to do. Failing to do so would be unconscionable.”