The governments of Switzerland and France have been accused of breaching the human rights of their citizens by not acting decisively enough on climate change, at a landmark legal hearing in Strasbourg. A panel of judges at the European court of human rights heard petitions from a group of Swiss women and a French former mayor seeking to bolster climate action in their countries. Although climate litigation has spread quickly around the world, these are the first such cases to be heard by the ECHR. In the first lawsuit, a group of Swiss women over the age of 64 known as the KlimaSeniorinnen Schweiz (Senior Women for Climate Protection Switzerland) argued they were particularly vulnerable to the climate crisis because heatwaves, which are becoming more frequent and intense, put their health at risk. Supported by Greenpeace Switzerland, they want the court to order Switzerland to set tougher emission reductions targets and to do everything in its power to do its fair share to keep the global temperature rise to below 1.5C. A contingent from the KlimaSeniorinnen travelled to Strasbourg to hear their arguments being made in front of the court’s grand chamber, which is reserved for the most serious and novel cases. Elisabeth Stern, 74, who is on the organisation’s board, said it felt like “a historic moment”. During the hearing, the KlimaSeniorinnen’s legal team presented evidence that older adults suffer worse than others during periods of extreme heat and are more likely to die. Older women are even more vulnerable. The British barrister Jessica Simor KC, who is representing the women, told the court her clients were already experiencing the effects of climate change, which posed “extremely serious threats not just to their health and wellbeing but to their very existence”. She claimed that this breached articles two and eight of the European convention on human rights, which protect the right to life and to respect for private and family life. Marc Willers KC, another British barrister representing the women, argued that the Swiss government’s progress in meeting its existing climate targets was “woefully inadequate”. He said these goals were in any case too weak for Switzerland to do its fair share to stay within 1.5C. Scientists recently said swift and drastic action was needed to avoid irrevocable damage from rising greenhouse gas emissions. The Swiss government agreed that rising temperatures harmed people’s health. But it denied that KlimaSeniorinnen should be treated as victims under the law and said the link between its actions and their suffering was “too tenuous and remote”. It said some of the claimants, several of whom are over the age of 80 – another has died since the case was filed – were unlikely to be alive by the time the global temperature rise potentially breaches the 1.5C threshold. Switzerland maintained that its climate targets were strong enough and said the actions it had taken so far “demonstrate a willingness” to limit warming to 1.5C. Despite her initial optimism, Stern said she was disappointed by her government’s responses. “I almost feel a bit ashamed for them,” she said. The second lawsuit in front of the court was brought against the government of France by Damien Carême, a former mayor of the northern municipality of Grande-Synthe and now a Green MEP. As mayor, Carême petitioned the French president, prime minister and environment minister to do more to cut national emissions, and he says he was rebuffed. His attempts to seek legal redress were partly successful when in 2021 one of France’s highest courts ordered the government to take “all necessary additional steps” to reach its climate targets. But Carême disputed the court’s decision that he was not directly affected by France’s failure to take sufficient action on climate change. Carême, who lives on the coast near Calais, said his home was at serious risk of flooding and could be completely submerged by 2030. He said this was a threat to his life as well as his health. The French government told the court that Carême should not be considered a victim under the law and called on it to strike out the case. The 17-judge panel is considering its decisions. If it rules in favour of the Swiss women or Carême, it could order their governments to do more to cut emissions, and its judgments are legally binding.