Four major oil companies aren't taking concrete steps to live up to their pledges to transition to clean energy, new research has found.

The study, published Wednesday in the journal PLOS One, found that Chevron, ExxonMobil, BP and Shell used terms like "climate," "low-carbon" and "transition" more frequently in recent annual reports and devised strategies around decarbonization. But their actions on clean energy were mostly pledges and the companies remain financially reliant on fossil fuels.

"We thus conclude that the transition to clean energy business models is not occurring, since the magnitude of investments and actions does not match discourse," the researchers at Tohoku University and Kyoto University in Japan said.

"Until actions and investment behavior are brought into alignment with discourse, accusations of greenwashing appear well-founded," they added.

The four major oil companies the study focuses on account for more than 10% of global carbon emissions since 1965, the researchers said.

Global energy companies have been promising a transition to clean energy – or at least reducing their carbon footprint – as pressure grows from environmental advocates, shareholders and governments to reduce greenhouse gas emissions in order to stave off the worst effects of climate change.

The companies have taken particular heat from critics who say they misled the public about the dangers of climate change for years and are now doing too little to address the warming planet.

Still, the energy sector isn't unified in how exactly to achieve that goal, and the study concludes that the world's largest publicly traded oil and gas companies are underperforming on their clean energy targets.

The paper found scant evidence of a major shift away from fossil fuels

Using data collected from 2009–2020, the researchers found that the companies often talked about shifting to clean energy without making dramatic changes that would enable them to make a company-wide transition.

For example, the paper said BP and Shell have vowed to reduce investments in fossil fuel extraction projects. Instead, they have increased acreage for new oil and gas exploration in recent years.

The researchers said they found no evidence that the companies were investing in clean energy at a scale that would allow them to shift away from fossil fuels.

In fact, the study noted: "Glaringly, ExxonMobil generated no clean energy during the decade." BP's global renewables capacity — the largest among the four majors — amounts to only 2,000 MW, or the the equivalent of about two large gas-fired power plants.

Also, the two European companies — BP and Shell — more consistently acknowledged climate science, invested more on clean energy and took more aggressive steps than their American counterparts — ExxonMobil and Chevron — which "exhibit defensive attitudes" toward investing in renewable energy and moving away from fossil fuels, the paper found.

The companies say they're moving toward clean energy

A spokesperson for Chevron, based in San Ramon, Calif., said the company couldn't comment directly on the paper because they hadn't seen it, but that Chevron is focused on "lowering the carbon intensity in our operations and seeking to grow lower carbon businesses along with our traditional business lines." Chevron is planning to put $10 billion into lower carbon investments by 2028.

BP, headquartered in London, said through a spokesperson that because the company made major advancements toward its net zero goals in 2021, it doesn't believe the paper fully accounts for its progress. For example, the company said it made $1.6 billion in capital investments in low carbon energy last year. BP also reported that its oil and gas production declined during the period the researchers studied.

"We have already made important strategic progress – for example, quadrupling our renewables pipeline and almost doubling our EV charge points since 2019 – and have recently further defined and evolved both our strategy and net zero ambition," the BP spokesperson said. The study said BP stood out for "increasing the proportion of investments in non-fossil fuel businesses and gradually reducing hydrocarbon production ... and exploration."

A Shell spokesperson said the company, also headquartered in London, is aiming to have net-zero emissions by 2050 – including both the energy it uses and sells – and that it was the first energy company to submit its transition plan to shareholders, who approved it.

ExxonMobil said it expects oil and gas production to be more or less flat through 2025, a spokesperson said. The firm, based in Irving, Texas, has also vowed to make $15 billion worth of lower-emission investments through 2027 and has "progressed more than 20 lower-emissions projects around the world."