(Bloomberg) — Oil companies risk wasting $2.3 trillion of investments should demand peak in the next decade as the world works toward its goal of limiting global warming, according to a report from Carbon Tracker.

Exxon Mobil Corp. is the most exposed oil major with as much as 50% of potential spending to 2025 on projects that wouldn’t be needed as the world changes its energy mix to meet climate targets, according to the report published on Wednesday in collaboration with the Principles for Responsible Investment. Royal Dutch Shell Plc, Chevron Corp., Total SA and Eni SpA risk wasting as much as 40% of expenditure and BP Plc up to 30%.

The energy industry is debating the role it will play in the transition to a low-carbon world as investors raise questions about the viability of future spending amid attempts to limit global warming. Shell says oil demand may peak in the second part of the next decade, while BP thinks it could happen in the 2040s.

“There are clear signs that oil demand could peak in the early 2020s — so companies need to start taking project options that would come on stream then off the table, and be transparent about how they are aligning with a low carbon future,” James Leaton, Carbon Tracker’s research director, said in the report. “Sticking with the growth at all costs scenario just doesn’t add up for shareholder value when the policy and technology momentum is heading in the opposite direction.”

The companies are already facing some pressure from investors. Last month, Exxon shareholders, in a split with the company, urged the explorer to publish a detailed analysis on how carbon curbs could affect the value of its oil fields, refineries and pipelines. While Shell investors voted against a resolution asking the company to publish targets for reducing greenhouse gas emissions, it continues to face demands to raise investment in renewable energy and cut down on oil and gas.

Under a business-as-usual outlook, capital expenditure and production would generate 380 billion tons of carbon dioxide by 2035, the report showed. Oil companies would have to avoid projects generating 60 billion tons of CO2 to be consistent with the International Energy Agency’s scenario that gives the world a 50% chance of limiting warming to 2 degrees Celsius.

Exxon, BP and Shell are among majors that have said they support the Paris climate agreement to limit greenhouse-gas emissions, with BP CEO Bob Dudley describing the transition to a low-carbon economy as inevitable.

While peak demand would hurt private companies, it would have a milder impact on Saudi Arabian Oil Co., which is planning the world’s biggest share sale next year. No more than 10% of the explorer’s spending risks going to waste because of its low cost of production.

Bloomberg News by Rakteem Katakey