The state attorney general leading the investigation into Exxon Mobil over climate change appears to be shifting gears in a Democratic probe that has suffered from recent pushback in the courts.

Democratic New York Attorney General Eric Schneiderman told the New York Times in a Friday article that he is pursuing a new tack in going after the oil company for not being forthcoming to the public about global warming. It's a charge that Exxon says is false and has fought in the courts to redact as an affront to free speech.

Nevertheless, Schneiderman appears to be changing his strategy from going after Exxon for what it knew about climate change in the 1970s, but withheld, to what it is currently predicting to protect its oil reserves from becoming stranded assets.

"The older stuff really is just important to establish knowledge and the framework and to look for inconsistencies," Schneiderman told the Times.

Schneiderman subpoenaed the company and groups it is aligned with to gain emails and documents on its climate change policy. The investigation started after the publication Inside Climate News and the Los Angeles Times reported that Exxon had covered up studies by its own scientists beginning 40 years ago that showed climate change was a threat to its business.

"Allegations by media and environmental activists about the company's climate research are inaccurate and deliberately misleading," said Scott J. Silvestri, an Exxon Mobil senior media adviser, in an email to the Washington Examiner. "To suggest that we had reached definitive conclusions, decades before the world's experts and while climate science was in an early stage of development, is not credible."

But now, the New York Times reports, "the question for Mr. Schneiderman is less what Exxon knew, and more what it predicts."

For example, Schneiderman told the Times that his investigation is scrutinizing a 2014 company report that showed it would not have to leave its enormous oil reserves in the ground as "stranded assets" even with increased global efforts to cut carbon pollution.

Schneiderman argues that even burning a portion of that oil in the ground would heat up the Earth to such dangerous levels that "there's no one left to burn the rest," which he asserts is based on what some scientists suggest.

"By that logic, Exxon Mobil will have to leave much of its oil in the ground, which means the company's valuation of its reserves is off by a significant amount," the Times wrote.

Schneiderman said: "If, collectively, the fossil fuel companies are overstating their assets by trillions of dollars, that's a big deal." It is an especially big deal if the company's own internal research shows it knows better, he added. "There may be massive securities fraud here," he said.

But Exxon believes that argument is convoluted and a bit farfetched. Exxon Mobil spokesman Alan Jeffers said if the company's forecast "turns out to be wrong, that's not fraud, that's wrong."

"That's why we adjust our outlook every year, and that's why we issue the annual forecast publicly, so people can know the basis of our forecasting," Jeffers said.

The oil industry's pro-fossil fuel campaign, Energy in Depth, said Schneiderman's change in tune is in response to "overwhelming opposition" from legal experts, mainstream media editorial boards, and even some of the 19 attorneys general in his climate coalition.

"After months of the #ExxonKnew campaign telling us that these investigations are happening because the company 'knew' about climate change in the 1970s and 1980s and then 'lied' about it (and as Schneiderman continues to refuse to comply with public records laws) Schneiderman is now telling the New York Times that Exxon's past statements are not the focus of his investigation at all," Energy In Depth said in a blog post. "New York Attorney General Eric Schneiderman is completely changing his tune and attempting to reboot the reason behind his investigation into Exxon Mobil."

Exxon Mobil has said that it accepts that climate change is occurring and supports enacting a fee on carbon pollution to combat it.

"The risk of climate change is clear and warrants action," Silvestri said. "Exxon Mobil is taking action by reducing greenhouse gas emissions in its operations, helping consumers reduce their emissions, supporting research and participating in constructive dialogue on policy options."

Earlier this week, several of the Democratic attorneys general sent a letter pressing Rep. Lamar Smith, R-Texas, who is chairman of the House Science Committee, to stop his investigation into Schneiderman's probe. Smith recently subpoenaed the New York attorney general for emails and documents related to his investigation into Exxon Mobil.

The letter sent by 12 Democratic attorneys general said Smith's subpoenas "exceed Congress' constitutional authority." The subpoenas that were issued to the New York and Massachusetts attorneys general should be withdrawn, the letter read.

"Your interference in our colleagues' work ignores a 'vital consideration' under our constitutional system of dual sovereignty: the preservation of comity between the federal government and the states," the letter said.