Announcing on Earth Day what it said was the industry's most ambitious climate target, the British company said it would also work with media partners in television and online to ensure its supply chain is a net zero producer by 2030.

The owner of the GroupM, Ogilvy and Hill+Knowlton agencies joins a long line of multinational companies and governments that have set out targets to cut carbon emissions by switching to renewable energy sources, reducing travel and reviewing operations.

It said it had an independently assessed annual carbon footprint of 5.4 million tonnes of carbon dioxide equivalent.

"WPP is the world's largest buyer of advertising space, managing more than $60 billion in media spend on behalf of our clients, and the world's largest producer of advertising content," Chief Executive Mark Read said. "So we have the opportunity to make a real difference."

WPP, which produces advertising, designs strategies on where to place it and produces PR and data analysis, said the pandemic had accelerated innovation in virtual production technology and reduced the need for staff to gather at carbon-intensive location shoots.

The firm, which competes with Omnicom, IPG and France's Publicis, said it would work with its media partners to develop an industry-wide standard for measuring the carbon that is emitted through the placement of advertising.

"(Its media buying arm) GroupM is consolidating its existing carbon calculators to allow a single view of emissions across channels in key markets, and make them available to clients at scale," it said.

The group added that it expected carbon data to increasingly become part of the information that is requested when ad firms pitch to run ad campaigns for brands.

(Reporting by Kate Holton; editing by James Davey/Guy Faulconbridge/David Evans)

By Kate Holton