NEW YORK – The fossil fuel industry risks losing $33-trillion in revenue over the next 25 years as global warming may drive companies to leave oil, natural gas and coal in the ground, according to a Barclays Plc energy analyst.

Government regulations and other efforts to cut carbon emissions will inevitably slash demand for fossil fuels, jeopardizing traditional energy producers, Mark Lewis, Barclays’s head of European utilities equity research, said Monday during a panel discussion in New York on financial risks from climate change.

His comments are part of a growing chorus calling for more transparency from oil and gas companies about how their balance sheets may be affected by the global shift away from fossil fuels. As governments adopt stricter environmental policies, there’s increasing risk that companies’ untapped deposits of oil, gas and coal may go unused, turning valuable reserves into stranded assets of questionable value.

“There will be lower demand for fossil fuels in the future, and by definition that means lower prices” Lewis said.

Stranded Assets

The meeting Monday was organized by the Task Force on Climate Related Disclosures, a group established last year by Bank of England Governor Mark Carney. It seeks to bring transparency and consistency to how companies warn investors about dangers they face from climate change. The group, led by Bloomberg LP founder and majority owner Michael Bloomberg, is drafting voluntary guidelines for companies to disclose risks related to coastal flooding, carbon-dioxide emissions and shifting global energy policies.

A “child with an abacus” can calculate that there are tremendous amounts of gas and oil that will need to be left in the ground, said Anne Simpson, investment director of global governance at the California Public Employees’ Retirement System, the largest US public pension fund.

“Yet we have boards of directors who will not talk to their shareholders about this issue,” Simpson said.