Aberdeen Standard Investments, Axa Investment Managers and 58 other big investors have demanded oil and gas companies intensify their efforts on climate change, in the clearest sign yet that asset managers and pension funds are increasingly concerned about the financial impact of global warming.

In an open letter to the Financial Times, the investors, which oversee almost $10.5 trillion in assets, call for the oil and gas industry to be “more transparent and take responsibility for all of its emissions.”

The letter comes ahead of a controversial vote at Royal Dutch Shell Plc’s (NYSE: RDS.A) annual meeting on May 22. Activist shareholders are pushing a resolution that would force the group to align its business with the Paris climate agreement, under which almost 200 countries agreed to limit global temperature increases to well under 2 degrees Celsius above pre-industrial levels.

The investors, which include Amundi, Europe’s largest asset manager, BNP Paribas Asset Management, Fidelity International, Newton Investment Management and Legal & General Investment Management, stopped short of endorsing the Shell resolution in the letter. But they said: “Regardless of the result at the Shell AGM, we strongly encourage all companies in this sector to clarify how they see their future in a low-carbon world.

“This should involve making concrete commitments to substantially reduce carbon emissions, assessing the impact of emissions from the use of their products and explaining how the investments they make today in energy sources and technologies are compatible and consistent with a pathway towards the Paris goal.”

The letter acknowledged that Shell had gone further than other oil and gas groups by setting an “ambition” to reduce its carbon footprint—including emissions from use of its products—by 50% by 2050. It is the only oil major to have acknowledged responsibility for the carbon emitted by its customers, as well as emissions from its own operations.

There’s a lot more we can accomplish through engagement, rather than divestment

However, Follow This, the Dutch group behind the shareholder resolution, said Shell’s goal was not firm enough and fell short of what was needed to meet the Paris target. Shell has urged investors to reject the resolution on the basis that it would bind the company to too rigid an approach.

Several U.S. oil and gas companies are also facing shareholder votes on climate resolutions in coming weeks. This reflects mounting pressure on the industry to take responsibility for the environmental impact of its products and become more transparent about the risk to business models as the world shifts towards cleaner forms of energy.

While climate activists have led the push against fossil fuel companies, the signatories of the Financial Times letter included many of Europe’s largest asset managers in a sign that mainstream institutional investors are becoming more engaged in the issue.

Aviva Investors, BMO Global Asset Management, Old Mutual Global Investors, Schroders and HSBC Global Asset Management also signed the letter, alongside several big pension funds.

The investors warned that regulations to keep global warming increases below 2 degrees would create “additional costs for carbon-intensive industries and risk stranding assets,” meaning that some oil and gas reserves could become uneconomic to produce.

They also urged policymakers to take clearer and more collective action on implementing regulation that will support investment in lower-carbon technologies.

After years in which pressure groups pushed for investors to divest entirely from fossil fuels, the trend has shifted toward demands for more transparency and accountability. “There’s a lot more we can accomplish through engagement, rather than divestment,” said one sustainable finance banker.

However, the subject is still considered a delicate one. Several of the signatories to the letter have related businesses that advise oil and gas companies.