Rishi Sunak attempted an extraordinary volte-face on green policy on the eve of the Cop27 climate summit on Saturday, saying he would attend in order to “galvanise” world leaders to save the planet. The prime minister – who had been criticised for saying he was too busy with domestic commitments to attend – also adopted precisely the same language on renewable energy that Labour leader Keir Starmer has been using for months, declaring that he now wanted to turn the UK into a “clean energy superpower”. Sunak’s efforts to present himself as a world leader on the environment and a champion of clean energy brought deep scepticism as political leaders, diplomats and NGOs gathered in the Egyptian resort of Sharm el-Sheikh for the latest UN-led attempt to tackle global heating. Writing in today’s Observer, Starmer ridicules Sunak, branding him “a fossil fuel prime minister in a renewable age”, who still wants to ban more onshore windfarms and who has opposed solar projects. Prof Saleemul Huq, director of the International Centre for Climate Change and Development, who is at the summit, said: “He has already exhibited his disinclination to make the UK a leader in the global fight against human-induced climate change by initially refusing to come to Cop27 and hand over the presidency from Cop26 to Egypt at Cop27. His actions to allow drilling for more fossil fuels in the North Sea are exactly the opposite of leadership.” During his leadership campaign against Liz Truss, Sunak vowed to maintain planning rules that effectively prevent any more onshore wind farms and also criticised solar power. But in a speech at the summit on Monday, Sunak will say: “Fighting climate change is not just a moral good – it is fundamental to our future prosperity and security. Russia’s invasion of Ukraine and contemptible manipulation of energy prices has only reinforced the importance of ending our dependence on fossil fuels. “We need to move further and faster to transition to renewable energy, and I will ensure the UK is at the forefront of this global movement as a clean energy superpower.” With most experts believing that the UK cannot become a “clean energy superpower” without more onshore as well as offshore wind, Downing Street denied that Sunak was preparing to change policy on onshore wind. A government source said that the emphasis would be on expanding offshore wind for the time being. As the UK hands over the Cop presidency to Egypt, Sunak will also urge leaders not to backslide on the promise of Cop26, where countries came together to sign the landmark Glasgow climate pact. The PM decided to attend the meeting last week only after criticism from other countries, and after the Observer revealed that his predecessor but one, Boris Johnson, was planning to go, threatening to upstage him. Greenpeace UK’s head of politics, Rebecca Newsom, said: “If Sunak wants the UK to be a global climate leader, he needs to rule out new oil and gas drilling, invest in home insulation, and back the demands of developing nations for a loss and damage finance facility. He should increase taxes on the profits of the fossil fuel giants to help pay for it, alongside giving extra support to households struggling with their bills. This is the only way we can deliver climate justice and build the trust that’s sorely lacking in international climate talks. People will soon forget what the prime minister said at this summit, but they will long live with the consequences of his actions.” Leading climate experts and campaigners fear the summit could fail before it even starts if countries do not agree to put the loss and damage suffered by the poorest countries at the heart of the talks. Huq said: “I am hopeful that there will be progress at last on finance for loss and damage at Cop27. There are discussions on whether to include it in the Cop agenda or not. Failure to include it will mean the Cop failing before it even starts officially.” If the issue is to be discussed, under the UN rules, an agenda item must be agreed at the opening session. There is willingness among developed and developing countries for such an item, but the Observer understands that some large developing economies are shying away from the issue. Harjeet Singh, head of global political strategy at Climate Action Network International, called for developed countries at the talks to take a lead. “Rich governments must engage in a constructive manner to address the ongoing injustice of climate-induced loss and damage, by committing to deliver support to those being impacted and by phasing out fossil fuels,” he said. “This is the Cop where polluters must be put in the dock and be held accountable.” Cop27, the latest edition of the annual UN climate talks, is taking place amid high geopolitical tensions over the Ukraine war, soaring energy and food prices and a cost of living crisis around the world. Even the Egyptian hosts have admitted this will be the most difficult set of talks in at least a decade. António Guterres, the UN secretary general, said in an interview on the eve of the talks that there was a gulf between the rich – which had caused the climate crisis but failed to cut greenhouse gas emissions – and the poor, which were suffering the impact but lacked the financial resources to protect themselves.