WASHINGTON—Political feuding over global warming reached the Securities and Exchange Commission Wednesday when commissioners, divided on party lines, voted to encourage companies to disclose the effects of climate change on their business.

SEC Chairman Mary Schapiro, an Obama administration appointee, said the agency wasn't weighing in on the global-warming debate and wanted to ensure that investors get reliable information.

The agency's two Republican commissioners voted against issuing the guidance. "I can only conclude that the purpose of this release is to place the imprimatur of the commission on the agenda of the social and environmental policy lobby, an agenda that falls outside of our expertise," said Republican Commissioner Kathleen Casey.

Two Republican lawmakers from the House Energy and Commerce Committee also took a swipe at the SEC in a letter sent Tuesday, calling the move "transparently political and such a breathtaking waste of the commission's resources."

Social investment groups have been urging the SEC for years to require more disclosure on climate matters.

Meredith Cross, director of the SEC's corporation-finance division, defended the move, saying large investors wanted the information.

"Investors have a fundamental right to know which companies are well positioned for the future and which are not," said Anne Stausboll, chief executive of the California Public Employees' Retirement System, of Calpers, the nation's largest public pension fund.

Insurance companies are among those affected by the SEC action. The agency said insurers may want to consider disclosing whether severe weather or changes in sea levels might increase the risk of claims in coastal regions.

The SEC also said companies should weigh disclosure on how pending rules or laws might affect the bottom line. For example, it noted, goods that produce significant greenhouse-gas emissions might see lower demand.

Peter DeSimone, the director of programs at the Social Investment Forum, said his group will ask the SEC "to intervene and enforce...in case where we see there's a clear lack of disclosure." He said insurance companies, oil and gas companies and car makers would be of particular interest to the forum, which focuses on socially responsible investing.

The Environmental Protection Agency is preparing to regulate greenhouse gases and Democrats and Republicans in Congress are sparring over whether to pass new laws to mandate reductions in greenhouse-gas emissions.

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