An Italian court is to rule on the country's first climate lawsuit against the state, with claimants hoping Rome will be ordered to slash greenhouse-gas emissions sharply.
The case, known as "Giudizio Universale" (Last Judgment), was launched in June 2021 by environmental group A Sud and more than 200 other associations and individuals.
They accuse the state of violating fundamental rights by failing to take sufficient action to meet the goals laid out in the landmark 2015 Paris agreement to reduce carbon emissions.
"I joined the trial because I have a mission to inform society about the risks we face due to climate change," climatologist Luca Mercalli, one of the claimants, told AFP.
A win would put pressure on "institutions to be much faster and more concrete in addressing the climate crisis", said Mercalli, who moved to the mountains in northern Italy to escape increasingly frequent heatwaves on the plains.
Scientists have long warned that humanity's burning of fossil fuels is warming the world with disastrous consequences for the environment.
In what promised to be a historic case for Italy -- a Mediterranean country exposed to multiple climate calamities -- the claimants initially asked a court to find the state responsible for contributing to the crisis, and to order it to cut emissions by 92 percent compared with 1990 levels by 2030.
But a Rome court agreed in 2024 with the state's argument that civil courts do not have jurisdiction over decisions made by governments on climate.
It was "a unique ruling in Europe", Luca Saltalamacchia, lawyer for A Sud, told AFP.
"Courts either rule in favour of the plaintiffs and order the state to act, or they dismiss the case on its merits.
"Never before in a European country has a judge simply said, 'No, I cannot rule'," he said.
Fresh evidence
The claimants have appealed, pointing to litigation -- particularly a 2024 European Court of Human Rights ruling in a Swiss case -- supporting their arguments linking climate protection with human rights.
They submitted fresh scientific evidence, from data on vast numbers of excess deaths due to heat in Italy, to forecasts on desertification and floods.
The Rome appeals court is due to rule later this month.
Saltalamacchia said the claimants hope the court will not only agree to examine the merits of the case, but "order the state to improve its climate policies".
"There are norms -- such as the Paris agreement -- that require the state to take specific steps which, in our view, have not been taken," he said.
Under the Paris accord, countries agreed to pursue efforts to limit warming to 1.5C above preindustrial levels, but scientists now say that threshold could be breached by about 2030.
A 2022 reform of Italy's constitution also added that the state must "protect the environment, biodiversity and ecosystems, also in the interest of future generations".
But Europe is warming at roughly twice the global average, according to the World Meteorological Organization (WMO), and Italy is increasingly victim to extreme weather events.
Human rights
Jameela Joy Reyes, an expert in climate law with the Grantham Research Institute at the London School of Economics (LSE), said the case "falls under the umbrella of 'government framework cases': cases filed against governments that challenge their ambition or the implementation of their climate targets."
There have been around 160 such cases worldwide so far, with 15 or so new cases filed in the last year, she said.
"The cases initially filed saw courts be more hesitant in making pronouncements. In more recent cases, we've seen more active decision-making from courts," Reyes told AFP.
At least 200 cases against governments have reached the highest court in their jurisdiction since 2015, and of those, more than half resulted in outcomes positive for climate action, she said.
A Sud points to a trial between Greenpeace and energy giant Eni, which saw Italy's highest court last year reject the very argument that no judges have the authority to rule on climate-related lawsuits.