Mrs. Clinton and Mr. Sanders have also called for an investigation into Exxon Mobil.

While Exxon’s chief executive, Rex W. Tillerson, was not in charge of the company four decades ago, he famously said at a shareholder meeting two years ago, “What good is it to save the planet if humanity suffers?”

Mr. Gore said that he “did not even know where to begin in responding to that.”

Shortly after leaving politics 15 years ago, Mr. Gore became occupied in helping to run his firm, Generation Investment Management, which is focused on investing only in sustainable companies. He describes his portfolio as “concentrated” and is invested in global equities.

With a “sustainability lens,” Mr. Gore said, he and his team research everything from how a company treats its employees to how it deals with its local community.

“There is a very narrow slice of the value spectrum represented in quarterly reports,” Mr. Gore said. “To harvest information that lies elsewhere, you have to organize yourself and build a team with routines and vocabularies that will integrate that into more of a complete picture.”