The number of insurers withdrawing cover for coal projects more than doubled this year and for the first time US companies have taken action, leaving Lloyd’s of London and Asian insurers as the “last resort” for fossil fuels, according to a new report.

The report, which rates the world’s 35 biggest insurers on their actions on fossil fuels, declares that coal – the biggest single contributor to climate change – “is on the way to becoming uninsurable” as most coal projects cannot be financed, built or operated without insurance, according to The Guardian.

Ten firms moved to restrict the insurance cover they offer to companies that build or operate coal power plants in 2019, taking the global total to 17, said the Unfriend Coal campaign, which includes 13 environmental groups such as Greenpeace, Client Earth and Urgewald, a German NGO.

At least 35 insurers with combined assets of $8.9tn, equivalent to 37% of the insurance industry’s global assets, have begun pulling out of coal investments. A year ago, 19 insurers holding more than $6tn in assets were divesting from fossil fuels.