During a long and fractious annual meeting in Dallas on Wednesday, Tillerson, who serves as Exxon's chairman and chief executive, beat back several proposals to force the company to take more action on climate change.

However, dissident shareholders won a vote that could make it easier for them to propose board candidates concerned about climate change and remove incumbent directors.

Tillerson said Exxon had invested $7bn in green technology, but the science and technology had not yet achieved the breakthroughs needed to compete with fossil fuels. "Until we have those, just saying 'turn the taps off' is not acceptable to humanity," he said. "The world is going to have to continue using fossil fuels, whether they like it or not."