A yearslong campaign to enforce climate reporting on public companies comes to a head Wednesday morning when the U.S. Securities and Exchange Commission votes on an environmental disclosure rule.

Commission Chairman Gary Gensler opened the meeting by endorsing the rule, saying that 90% of the largest public companies already provide climate-related information. He said the rule would standardize disclosures and make them comparable.

“The SEC has no role as to climate risk itself,” he said. “We have a role to play with regard to climate-related disclosures.”

The agency‘s final proposal is narrower than an earlier draft that had provoked sharp protests from many businesses, while a second item at Wednesday’s meeting would implement only a sliver of the Commission’s once grand plans to overhaul how stocks are traded. The meeting’s two trimmed-down proposals may show how Gensler’s reform ambitions have been curtailed.

The environmental rule would require publicly traded U.S. and foreign companies to account in their financial statements for significant costs resulting from hurricanes, drought, floods, fires, and other severe weather effects of climate change. The amount of greenhouse gas emitted by the business, or resulting from its electricity consumption, would also have to be disclosed.

In a seeming concession to industry criticism, the final proposal exempts the many companies with a float of publicly held shares smaller than $75 million. It drops the ambitious mandate of the 2022 draft calling for a company to report the greenhouse-gas emissions of its suppliers and customers. Many companies found that accounting for their supply chain’s emissions is currently not feasible.

When her turn came to talk at Wednesday’s meeting, Republican commissioner Hester Peirce lambasted the rule. It gives undue weight to climate risks, as opposed to other investment risks, and will be expensive for companies to implement, she said.

Still, approval by the commission is likely, given the commission’s majority of Democrats. If that happens, the climate disclosures would phase in through 2033. Firms with a public float above $700 million would have to begin disclosures of climate risks and costs in 2025 and quantify their carbon footprints with increasing certainty over the succeeding eight years. Smaller firms with floats down to $75 million would have more time and looser standards for their greenhouse-gas accounting.

Some privately held companies would have been required to account for climate impacts under the original proposal, either as suppliers or merger partners. That won’t happen under the final rule.

Environmentally conscious groups have long sought to bring pollution and climate change to the attention of investors. In 2010, the SEC issued guidance to public companies that wished to make voluntary climate-related disclosures. The commission proposed the first mandatory disclosures in a 500-page draft rule, issued in March 2022, that drew over 20,000 comment letters, supportive or bitterly critical. Meanwhile, the European Union and states such as California adopted their own climate reporting rules.