Exxon's annual meeting Wednesday will bring the most closely watched shareholder votes on global warming in Big Oil's history.

Driving the news: Activist investors Engine No. 1 have nominated four board members who would seek to make Exxon more aggressive on climate.

• Engine No. 1's backers include huge public pension funds in California and New York State, and the influential proxy advisory firm Institutional Shareholder Services recommends shareholders support it.
• Engine No. 1 also says Exxon lacks "any serious diversification efforts" that will prepare it to thrive in a low-carbon world. The group says Exxon needs a more disciplined capital investment approach around oil and gas.

Why it matters: It's the highest-profile effort by activist investors to force oil majors to diversify away from their dominant products more quickly.

It's also a fight over how Exxon, one of the world's most powerful corporations, should view the future after years of rocky financial performance.

The other side: Exxon management opposes the slate. The company says it's in step with the evolving energy mix, citing growing emphasis on carbon capture, hydrogen and biofuels.

• Exxon also argues its adjusted capital strategy will deliver strong returns in oil and gas, which it notes will remain huge markets for decades despite low-carbon energy growth.
• CEO Darren Woods tells the Washington Post that Engine No. 1 "have been very focused on what I would say is perceptions of the past."

The intrigue: The rebound in Exxon's share price over the last six months could bolster management. But a new wildcard emerged last week.

• An International Energy Agency analysis said a pathway to net-zero emissions in 2050 means no new oil and gas fields would be approved for development (investment in existing fields would continue).
•  "It gives a fund manager extra cover to justify voting against management, cover that isn’t provided by some call to arms from Greenpeace or the Sierra Club," Bloomberg's Liam Denning writes.