The BBC received about £300,000 in advertising revenue last year from Saudi Arabia’s national oil company, Aramco, despite BBC director general Tim Davie calling on every arm of the broadcaster to “dial up the focus on sustainability” and reduce net greenhouse gas emissions.

Although the BBC does not carry advertising in the UK, much of its overseas output is supported by commercials.

Big fossil fuel companies have spent approximately $660,000 (£483,000) with the BBC on US-focused digital adverts since 2018, according to projections produced by the advertising data firm MediaRadar. Most of this came from the national Saudi oil company – although BP, Exelon and Phillips 66 are among the other fossil fuel business estimated to have spent five-figure sums advertising on the BBC’s digital outlets.

The real figure for how much the BBC is making from large fossil fuel companies could be much higher when other forms of advertising are taken into account.

Last month the BBC said it would be trying to eliminate “fossil fuel usage across its operations” as part of a “deep decarbonisation” strategy to hit net zero by 2030, but the corporation has been accepting money from companies that take oil and gas out of the ground.

“We have clear guidelines around advertising which are publicly available,” said a BBC spokesperson. “We take care with all of our advertising to ensure it is not misleading.”

Davie has emphasised the need to increase the corporation’s commercial revenues, including from outside the UK, to make up for the real-terms cuts to the licence fee income imposed by the British government.

Despite continuing to accept money from big fossil fuel companies, the BBC is among the online publishers who have also benefited from the increase in advertising around environment-related material in recent weeks, as corporations rush to promote their green credentials before the Cop26 summit in Glasgow.

The BBC has struck deals with the international investment arm of the Scottish government to make a series of programmes on how to reduce carbon in the buildup to Cop26. There is also BBC material sponsored by US supermarket giant Walmart “looking at nine countries’ progress on climate since signing the Paris Agreement”, as well as episodes of a show called Follow the Food: The Carbon Challenge about food security, sponsored by Corteva Agriscience.

Using the same estimates from MediaRadar for US-focused digital advertising bought by big fossil fuel companies, the Washington Post has taken $12.8m since 2016, Politico took $9.5m, CNN took $6.6m, and the New York Times took $4.5m.

The Washington Post, Politico and CNN did not respond to a request for comment.

The New York Times repeated its commitment to journalism covering the climate crisis, but does not have a policy against accepting ad money beyond their general guidelines: “All advertising is clearly labeled, entirely separate from our newsroom and plays an important role in helping to fund our independent journalism and the continued expansion of our coverage on the biggest stories of our time, including climate change, across a breadth of analysis and formats.”