"Question" here means undermine and sow doubt. Exxon, and a few other big oil companies bankrolled the movement to create doubt about AGW years ago, even as their own research led them to make preparations for its effects. Ironically, Exxon and most of the rest of Big Oil now admit the hypothesis is true, but the doofus movement they founded soldiers on.

Big Oil braced for global warming while it fought regulations
http://graphics.latimes.com/oil-operations/