The UN secretary-general, António Guterres, will be seeking assurances from the UK that there will be no reneging on climate promises, after Rishi Sunak’s rowing back on green measures. The UN is concerned that countries may be backsliding on pledges to cut greenhouse gas emissions sharply, to limit global temperature rises to 1.5C above pre-industrial levels. Top UN officials called for countries to put aside geopolitical tensions in order to make progress on tackling the climate crisis at the crucial Cop28 climate summit in Dubai, which begins on 30 November. Amina Mohammed, deputy secretary general, said the UN was “absolutely” concerned about backsliding on climate commitments because “there is a lot of it”. Countries made pledges last year, at the Cop27 summit in Egypt, and at the landmark Cop26 summit in Glasgow in 2021, where the 1.5C limit was strongly affirmed. Many countries have since appeared to waver, through expanding fossil fuel access after the invasion of Ukraine, or by failing to set strong targets. In the UK, the prime minister has said the legally binding target of reaching net zero emissions by 2050 still stands, but recent actions, such as postponing the phase-out of petrol driven cars and gas boilers, make it doubtful the UK will meet its emissions reduction commitments for 2030. In the US, Joe Biden has licensed new oil and gas developments, despite taking a strong stance on the climate crisis. The EU has also recently failed to toughen its commitment to emissions reduction, currently set at a 55% cut by 2030 compared with 1990 levels, and China and India continue to invest in coal. “Certainly, the secretary general will be leaning in to have those conversations with countries like the UK, the US, China, many [others]. It doesn’t stop,” Mohammed told the Guardian. “We have to keep them in the room [discussing climate action]. We need to get out of everyone the best of the ambition that is expected from us.” She said backsliding was a problem. “We have to call that out and it has to reverse itself. There is a lot of it. And this is what brings more mistrust into the room, that suddenly the goalposts may be changing.” Simon Stiell, executive secretary of the UN Framework Convention on Climate Change and the UN’s top climate official, said in the same interview: “Those [countries] who have the ability to go further, fastest [on cutting emissions] must, and those that can, that aren’t – I think they’re already being called out.” The Cop28 meeting will take place at a time of rising global tensions over the Israel-Hamas war and Russia’s invasion of Ukraine. Mohammed said the climate summit was happening “in very difficult times”, but called on countries to put these tensions aside for the two-week Dubai meeting. “[We need] the signals that come from ministers, to give negotiators a green light to bring ambition into this and find solutions. It’s very easy not to find the solutions and to get lost in the geopolitical tensions that are around. But if we could get leadership [from heads of government], we could probably get a lot done,” she said. Stiell added: “We know what needs to be done, we know how it needs to be done. It does boil down to this well-worn phrase of the political will to actually action the elements that are on the table, that are being negotiated right now. It’s turning those words to action, and it’s incumbent on every minister that will be participating in Cop28 and every head of state.” He said countries must reduce emissions far faster: “Parties cannot wait, the science tells us that very clearly. They are moving too slowly.” Sunak will face a difficult summit at Cop28, given doubts over the UK’s commitments. King Charles is to make a keynote address to the summit, at the request of the hosts. He takes a keen interest in the climate talks, and hosted the Cop28 president, Sultan Al Jaber, at a public reception and private meeting in Buckingham Palace earlier this year. Claire Coutinho, the UK’s energy security and net zero secretary, will attend Cop28, the government confirmed. She said: “No major economy has cut emissions faster than the UK. We’re proud that we’ve overdelivered on every target to cut our emissions to date. “However, tackling climate change is a global challenge, as the UK only accounts for 1% of worldwide emissions. I look forward to representing the UK at Cop28, where we will be working to get more progress around the world on green finance, forests, and clean energy. In the UK, we have more ambitious climate change targets than our peers and we will be using what we have learned to help others on our shared path to net zero.”