Rishi Sunak will call for a "global mission for new jobs and clean growth" as he joins world leaders for the first day of COP27 in Egypt.
The PM, who only announced he would be attending the climate change talks in a U-turn last week, will tell attendees today it is essential countries stick to commitments made in Glasgow last year if warming is to be limited to 1.5C.
After touching down on Sunday night, COP27 will be Mr Sunak's first outing representing the UK on the world stage since becoming prime minister last month. He will join others including US President Joe Biden and French President Emmanuel Macron.
In his opening address in Sharm El-Sheikh, the PM will argue the transition away from fossil fuels can drive growth and deliver jobs in new green industries of the future, while cutting off funding for Russia's war in Ukraine.
"The world came together in Glasgow with one last chance to create a plan that would limit global temperature rises to 1.5C. The question today is: can we summon the collective will to deliver on those promises?" Mr Sunak is expected to say.
"I believe we can. By honouring the pledges we made in Glasgow, we can turn our struggle against climate change into a global mission for new jobs and clean growth.
"And we can bequeath our children a greener planet and a more prosperous future. That's a legacy we could be proud of."
UK funding for 'green technologies'
Downing Street said the PM will be looking to continue the success of last year's COP26 summit in Glasgow with more than £200m in UK funding to protect forests and invest in "green technologies".
This is expected to include a further £65.5m for the clean energy innovation facility which provides grants to researchers and scientists in developing countries, £90m for conservation in the Congo Basin rainforest and £65m to support indigenous and local forest communities.
But the prime minister has faced criticism back on home turf over the government's decision to issue more licences for oil and gas exploration in the North Sea and its continued opposition to new onshore wind.
And it is also not known if Mr Sunak will make an announcement on renewable energy, such as allowing more solar farms.
Labour's shadow climate change secretary Ed Miliband has called on the PM to drop the plans and end the government's opposition to onshore wind.
He told Sky News: "It makes no sense, and it makes a complete joke, frankly, of Rishi Sunak, the man who couldn't even decide whether he was going to go COP27.
"It makes a complete joke of the idea that he's somehow a leader on clean energy."
The prime minister had originally not been due to travel to COP27, saying his priority was preparing for his government's autumn budget later this month and sorting out the country's public finances.
But Mr Sunak was forced into a U-turn after critics, including members from his own party, questioned his commitment to tackling climate change.
This year's summit takes place against a backdrop of increasingly extreme weather events taking place around the world, coupled with both the energy and cost of living crisis exacerbated by the war in Ukraine.
The climate talks will continue until 18 November.
What's Labour's position?
As COP27 begins, Sir Keir Starmer is expected to set out Labour's plans to boost green industries and jobs across Britain by supporting the development of net-zero industrial clusters to boost local economies.
Labour says these net-zero industrial clusters will bring together heavy industries like cement, ceramics, steel, and chemicals, with the low-carbon technology of the future - carbon capture and storage and hydrogen - to provide a clean and prosperous future for the UK's industrial heartlands.
The Labour leader will also accuse the government of "dragging its feet on climate at every turn".
His climate change shadow minister Mr Miliband said: "Only Labour has a world-leading plan for 100% clean power by 2030 - to cut bills, deliver energy security, create jobs and industries here in Britain, and lead the world in tackling the climate crisis."
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