On Monday, the Intergovernmental Panel on Climate Change warned that the dangerous impacts of climate breakdown are already being felt and are accelerating rapidly. Has that message been heard? The second of four parts of the IPCC’s sixth assessment report, the latest comprehensive review of our knowledge of the climate crisis, was termed by some scientists “the bleakest warning yet”. Half of the world’s people are “highly vulnerable” to serious impacts from the climate crisis, a billion people in coastal areas face inundation, mass die-offs of species including trees and coral have already begun, and close to a tenth of the world’s farmland is set to become unsuitable for agriculture. By any standards, these are stark and brutal findings. António Guterres, the UN secretary general, said: “I have seen many scientific reports in my time, but nothing like this. Today’s IPCC report is an atlas of human suffering, and a damning indictment of failed climate leadership.” But the report has been overshadowed, understandably, by the war in Ukraine, and has received less policymaker and media attention than it deserved. That does not mean the IPCC report will be ignored. Governments are working on their responses to the scientists’ warnings, and later this year at the next UN climate summit, Cop27, they are obliged to lay out their plans to cut greenhouse gas emissions to limit global heating to 1.5C above pre-industrial levels. Will Cop27 be affected by the war in Ukraine? Cop27 is to be held this November in Egypt, a country that has forged strong diplomatic and economic ties with Russia in the recent past. Any meetings among the G20 major economies will also take place under the shadow of the Russian invasion of Ukraine. However, insiders point out that the climate negotiations have gone on for 30 years, despite wars and other conflicts among UN nations. Climate diplomats are practised at keeping other geopolitical tensions at least partly at bay. Perhaps of even greater relevance to the climate crisis will be the decisions governments make on energy policy in response to the Ukraine war. This week, the International Energy Agency urged a suite of actions – from households turning down their thermostats by 1C to windfall taxes on energy companies and the rapid construction of new wind and solar power generation – that could reduce the EU’s reliance on Russian gas by a third or more. The other options open to policymakers if Vladimir Putin turns off gas supplies to Europe would include a return to coal-fired power generation, the dirtiest form of fossil fuel. The choices that governments make now, ahead of next winter, will have profound consequences for the climate crisis. What actions could and should governments take as a direct result of the IPCC report? One of the key messages of the IPCC working group 2 report is that climate change is already occurring, all over the world. Even if we succeed in limiting global temperature rises to 1.5C, the limit countries agreed to target at Cop26 in Glasgow last November, we will still face more extreme weather, droughts, floods, heatwaves and sea level rises. The IPCC made clear that countries must seek to adapt now to these changes, to stave off the worst damage. Adaptation can mean building seawalls and river barriers, planting trees on hillsides to stop landslips amid floods, conserving or regrowing mangrove swamps to absorb the impact of coastal storm surges, painting roofs white to reflect the sun’s heat, or making buildings and built infrastructure such as telecommunications networks, roads and railways more resilient to extreme weather. Far too little effort has gone into adaptation up to now, the IPCC found. Rich countries promised last year at Cop26 to double their funding for adaptation in the poor world, but nearly all countries are still badly prepared. Will adaptation be enough? No. There are “hard limits” to adaptation, the IPCC made clear: the impacts of temperatures rising unchecked would overcome all our efforts to adjust. Flood barriers may hold back a river in spate today, but as the icecaps and glaciers melt, as heatwaves take hold, and as droughts threaten agriculture, we will face too many threats and they will grow too severe for any adaptation effort to allow life to proceed as normal. Cutting greenhouse gas emissions urgently, to stop temperatures rising further, must still be the priority, according to the IPCC. How should that be done? Early next month, the IPCC will release the third part of its four-part assessment, by working group 3, covering “mitigation” – the ways in which countries can reduce greenhouse gas emissions. This includes renewable energy generation, energy efficiency, alternatives to fossil fuels such as nuclear power, and novel technologies, such as carbon capture and storage and direct air capture of carbon dioxide. Working group 3 will set out pathways and policy choices governments could take to reach the goal of limiting global heating to 1.5C, including some of the likely costs and economic benefits of those choices. After that, a “synthesis report” drawing together all three parts of the IPCC’s sixth assessment will be published in October, for policymakers to discuss at Cop27.