Fifteen insurers have collectively divested about $US20 billion ($26.36 billion) in equities and bonds from coal companies, or ceased to underwrite coal projects, according to a new report.

The Insuring Coal No More Scorecard rates 25 of the world’s largest insurers and reinsurers on their investment exposure to the coal sector.

It says the shift away from coal is “gathering momentum” and may be approaching a tipping point after Axa became the first global insurer to reduce investment in coal in 2015.

Zurich recently announced plans to divest from and cease underwriting companies that depend on coal for more than 50% of their business.

Swiss Re and Lloyd’s have flagged new approaches, many of which go beyond the efforts undertaken by early movers such as Allianz, Aviva, Axa and Scor.

However, the report says US insurers lag behind their European counterparts, with none having taken meaningful action on coal and climate change.

Berkshire Hathaway, AIG and Liberty Mutual have remained “completely silent” about the catastrophic climate risks affecting their clients.

Elsewhere, Hannover Re, Chubb and Mapfre have taken no action on coal, while Generali and Munich Re have taken “baby steps”.

Dan Gocher from Australian environmental pressure group Market Forces, told insuranceNEWS.com.au the difference in attitudes between US and UK insurers comes down to “societal norms”.

“The US, like Australia, is still debating the science [of climate change], rather than trying to come up with a solution,” he said.

While Mr Gocher does not expect insurers in Australia to start immediately divesting from coal, he says it is a question of stopping the industry’s expansion.

“We’re a big coal exporter, but at least we can start to put the brakes on the industry,” he said.

As more insurers take action to exit the coal sector, the scorecard will be updated at UnfriendCoal.com.