For the first time in the European Court of Human Rights (ECHR) in Strasbourg, governments are on trial for purported climate change inaction.
The cases have been filed by an association of Swiss senior citizens and a French former mayor.
Why is Bern being sued?
The association of elderly people also called the "Club of Climate Seniors," has filed a case against Switzerland over concerns of global warming's consequences on their living conditions and health, according to the ECHR.
They blame the Swiss authorities for various climate change failings. The association says this amount to a violation of the government's mandate to protect life and citizens' homes and families.
Marie-Eve Volkoff, 85, is suing the government alongside the association with a membership of around 2,000 other elderly women for what she calls "climate lockdown".
Switzerland experienced heat waves in 2022, compelling Volkoff to stay indoors for 11 weeks with just short outings. Referring to the situation as a "climate lockdown" in which her activities are limited by conditions outside, she described the situation as worse than the COVID-19 pandemic and a violation of her human rights.
"I have had to enormously restrict my activities, to wait, with the blinds down and the air conditioning on — shame for an ecologist! — for the heat wave to pass, allowing me to go back to normal life," she wrote in a letter.
Other women in the case described shortness of breath, nausea and even loss of consciousness during the heat waves, which are increasing in frequency due to climate change.
This is the first-ever climate case before the ECHR. The hearing on Wednesday has been described as historic.
"This is a historic event," said Anne Mahrer, 64, a member of the Club of Climate Seniors.
French government in the court's dock too
Damien Careme, a former mayor in northern France has presented a case against France in the ECHR.
He said the central government has failed to meet its obligation to protect citizens' lives by not taking sufficient steps to prevent climate change.
At the French judiciary, Careme filed a case on behalf of his town and his own when he was mayor. He argued that climate change was raising the risk of his home being flooded.
Although the highest administrative court found in favor of the town against the central government, the individual case was thrown out. Prompting Careme to take it to the ECHR.
High stakes trials
According to Corinne Lepage, a former French ecology minister and one of Careme's lawyers, "the stakes are extremely high."
"If the European court recognizes that climate failings violate the rights of individuals to life and a normal family life, then that becomes precedent in all of the council's member states and potentially in the whole world," she said.
Strasbourg has fast-tracked the hearing, meaning judges are set to decide within a year instead of the usual three.