Residents say saltwater floods as high as 1.3m have surged since 2019, battering homes and damaging livelihoods.
The floods used to happen twice a year but now hit the island more than a dozen times annually, they say.
Swiss Church Aid (HEKS), an NGO helping the islanders, said Pari has lost 11 per cent of its surface area in the past 11 years.
“Where will we live? My ancestors, my parents, my children, and even my grandchildren were all born here,” said Mustagfirin, who like many Indonesians goes by one name.
He is one of the four residents calling for Holcim to reduce its emissions in the civil complaint filed in Zug, where the firm is headquartered.
Another is mother-of-three Asmania, who lost her seaweed farm to flooding and worries about her fisherman husband who trawls the sea in extreme weather for ever-smaller catches.
“We want to send a message to other corporations: Please stop thinking only about profits,” the 39-year-old said.
They are claiming 3,600 Swiss francs (US$3,800) each for damages and protection measures such as mangroves.
A resolution could take four years if it reaches Switzerland’s highest court, according to HEKS.
The islanders took aim at Holcim because no one has acted against a major cement company before, environmentalist Dewy said.
Cement manufacturing accounts for about 8 per cent of global CO2 emissions.
Last year, representatives for the islanders met with Holcim in a mediation process that was not fruitful, prompting the plaintiffs to file their lawsuit.
Holcim, which in 2019 sold its Indonesian operations to a local concrete firm, told AFP it places importance on climate but disagreed with the islanders.
“We do not believe that court cases focused on single companies are an effective mechanism to tackle the global complexity of climate action,” it said.