A NEW report from the United Nations will issue “the starkest warning yet” on the state of the climate crisis – piling pressure on the UK Government to pull its weight ahead of hosting the COP26 conference in Glasgow.

The report from the UN’s Intergovernmental Panel on Climate Change (IPCC), to be published this morning, is the first part of a review of current scientific knowledge about how the world is warming due to human activity.

It is the first such global assessment since 2013, when scientists found that global warming was “unequivocal” and human influence on the climate was clear, with the majority of warming since the 1950s extremely likely to be down to human activity.

The message in the latest report is expected to be even stronger, with warnings of how soon global temperatures could rise 1.5C above pre-industrial levels – a limit that countries have pledged to try to avoid breaching because of the dangerous consequences for humanity.

The document is set to arrive amid nervousness from the UK Government’s Treasury about the costs of bringing forward the plans needed to eliminate carbon from the economy by the middle of the century.

The UK Government is yet to publish its strategy to become net zero by 2050, five years after the SNP's promise to do so by 2045.

But a Treasury review of the costs or cutting emissions has been delayed since the spring, reportedly over fears the analysis will warn that the poorest households will be hit hardest by the ambition.

The net zero strategy, which will have knock-on funding impacts on the SNP’s plans to cut emissions, is likely to be at the centre of the Chancellor’s autumn spending review – which could including subsidies for green technology including hydrogen.

But the arrival of the latest IPCC report will do little to ease the pressure on the UK Government to bring forward action to cut emissions, despite the financial climate.

A summary report is being published after being approved in a process involving scientists and representatives of 195 governments that has taken place online over the last two weeks.

That means governments have signed off on the findings – and pressure will be on them to take more action at COP26, being held in Glasgow in November.

The report comes as global temperatures have climbed to 1.2C above pre-industrial levels and increasingly extreme weather – from record heatwaves and wildfires to downpours and devastating flooding – hits countries around the world.

UN climate chief Patricia Espinosa has warned that many countries have not brought forward new action plans for cutting their emissions – a key part of what they need to do before COP26 takes place.

Globally, action pledged to tackle the emissions pushing up temperatures is not enough to limit warming to 2C above pre-industrial levels, let alone the tougher 1.5C target.

Alok Sharma, the UK Government’s president-designate of COP26, has warned that failing to limit warming to 1.5C would be “catastrophic”.

He added that the IPCC report would be the “starkest warning yet” about what the future could hold.

In an interview with the Guardian, he said: “You’re seeing on a daily basis what is happening across the world.

“Last year was the hottest on record, the last decade the hottest decade on record.”

He said COP26 “has to be the moment we get this right”, adding: “We can’t afford to wait two years, five years, 10 years – this is the moment.

“I don’t think we’re out of time but I think we’re getting dangerously close to when we might be out of time.

“We will see (from the IPCC report) a very, very clear warning that unless we act now, we will unfortunately be out of time.

“Every fraction of a degree rise makes a difference and that’s why countries have to act now.

“We’re seeing the impacts across the world – in the UK or the terrible flooding we’ve seen across Europe and China, or forest fires, the record temperatures that we’ve seen in North America."

“Every day you will see a new high being recorded in one way or another across the world.”

But Mr Sharma refused to criticise the UK Government’s plans for further fossil fuel extraction, saying: “Future (fossil fuel) licences are going to have to adhere to the fact we have committed to go to net zero by 2050 in legislation.

“There will be a climate check on any licences.”