The world's biggest oil company is facing a rebellion over its hardline approach to global warming. The company has refused to follow rival oil companies in committing large-scale capital investment to environmentally friendly technology. Rockefeller ancestor John D. Rockefeller founded Standard Oil, the business at the core of Exxon Mobil. His dynasty sponsored four shareholder resolutions. One of these calls on the chief executive, Rex Tillerson, to relinquish his role as chairman in favour of an outsider. The London-based corporate governance advisory service Pirc will recommend that institutions support this proposal.