Every oil major is investing in projects that will undermine global climate change targets, according to analysis released today by Carbon Tracker.

Fossil fuel demand will have to fall to meet international climate targets agreed in 2015, and only the cheapest projects will deliver an economic return for investors, Carbon Tracker said.

However, 18 projects worth $50bn have been signed off by oil majors since 2018 that won't make money in such a scenario. That includes ExxonMobil's $2.6bn Aspen project in Canada, which is the first greenfield oil sands project in five years and will require an oil price of over $80 a barrel to deliver a 15 per cent return.

Demand for oil can be satisfied with projects that break even at below $40 per barrel, and pursuing higher-cost projects risks creating stranded assets that will never deliver adequate returns, Carbon Tracker said.

The think tank estimates that the world's largest listed oil and gas companies each spent at least 30 per cent of their investment in 2018 on projects that are inconsistent with the International Energy Agency's most ambitious low emissions scenario.

"Every oil major is betting heavily against a 1.5C world and investing in projects that are contrary to the Paris goals," said Andrew Grant, senior analyst at Carbon Tracker and report author.

Investment decisions on a further $21bn of projects inconsistent with a low-carbon world are due this year, Carbon Tracker pointed out.

The think tank is calling on investors to challenge companies' spending on new fossil fuel production. Report author Andrew Grant said: "The best way to both preserve shareholder value in the transition and align with climate change goals will be to focus on low-cost projects that will deliver the highest returns."

Of all the oil majors ExxonMobil has the greatest risk of stranded assets in a low-carbon world, with more than 90 per cent of potential 2019-2030 spending on new projects outside a 1.6C pathway.