Aviva Investors said on Monday it could ditch its stock and bond holdings in 30 of the world’s biggest corporate emitters of carbon if their boards failed to take sufficient action over climate change.

The move comes as asset managers including BlackRock and Legal & General Investment Management look to ratchet up the pressure on companies to form a plan to transition to a lower-carbon economy, ahead of the next round of global climate talks.

The British asset manager, part of insurer Aviva and which manages 355 billion pounds in assets, said its Climate Engagement Escalation Programme would target companies in sectors including oil and gas, mining and utilities.

The program would last between one and three years, depending on the specifics of the company concerned. Aviva declined to name the companies concerned, but is a big shareholder in leading oil majors including Royal Dutch Shell and BP.

Among the actions Aviva said it expects of the companies are that they commit to net zero carbon emissions by 2050 and ensure their plan to do so is in line with the Science-Based Targets Initiative, an NGO-led group that signs off on corporate climate plans.

The companies would need to integrate the climate goals into their business strategy, including capital expenditure plans; set short- and medium-term targets; align management pay with the goals; and ensure lobbying efforts supported the goals.

“For our engagement approach to have impact, it must be accompanied by a robust escalation process, including the ultimate sanction of divestment,” Mirza Baig, Global Head of ESG Research and Stewardship, said in a statement.

Progress would be monitored on a six-month basis, with escalation measures open to Aviva including voting against directors at the companies’ annual general meetings, filing shareholder resolutions and working with stakeholder groups to apply pressure, it said.

“This approach has the complete backing of our investment teams,” said David Cumming, Chief Investment Officer for Equities at Aviva Investors.

“By fully integrating our approach across stewardship and the investment teams, we will be able to maximize our ability to influence the companies we have targeted towards positive climate strategies.”

(Reporting by Simon Jessop; editing by David Evans)