ExxonMobil Corp. (NYSE: XOM) and accounting firm PwC must turn over documents related to the oil major's representations of the impact of climate change on its business and assets, the New York Supreme Court ruled on Oct. 26.

On Oct. 14, Attorney General Eric Schneiderman's office asked the court to compel PwC to comply with an August subpoena and hand over documents after Exxon said it would not permit the auditor to do so due to accountant-client privilege.

Schneiderman said Oct. 26 that "Exxon had no legal basis to interfere with PwC's production."

"I hope that today's order serves as a wake-up call to Exxon that the best thing they can do is cooperate with, rather than resist, our investigation," he said.

A group of state attorneys general, led by New York, said in March they would go after the world's largest publicly traded oil company for allegedly violating securities laws by soft-pedaling the dangers of climate change and efforts to fight it.

Schneiderman's office has also inquired why Exxon had not written down the value of its assets in the wake of a slump in oil prices.

Exxon plans to appeal the court's decision in the coming days. "We respectfully disagree with the court's ruling and intend to take an immediate appeal," said Alan Jeffers, spokesman for Exxon.

Exxon said New York's inquiry has periodically shifted focus, first by looking for misleading comments about climate change, then moving onto the value of its reserves and how they might be "stranded" in the ground by carbon regulation in the future.

Exxon said in September the that U.S. Securities & Exchange Commission is the right agency to vet how it books reserves and that it complies with accounting and securities laws.