Investigative climate organization DeSmog published a report Thursday, co-published with The Guardian in the UK, that ranks the big ad groups by how much they've helped ExxonMobil, Chevron, Shell and BP spend on U.S. advertising since the Paris Agreement on climate change was adopted a decade ago.   

According to the analysis, WPP is at the top. Its agencies have facilitated more than $1 billion in Big Oil ad spend since 2016, nearly double that of its closest rivals. Six current and former WPP employees (their names weren’t disclosed) told DeSmog that much of the company’s work with Big Oil appears to be in breach of its own 2022 climate policy. WPP is the only major holding company to have worked for all four oil companies on advertising projects since Paris, according to the report.  

WPP’s 2023 annual report states, “We have developed internal tools to help our people identify potentially environmentally harmful briefs. These tools embed climate-related issues within existing content review procedures across the organisation. The misrepresentation of environmental issues is governed by our Code of Conduct. We also ensure our policies reduce the risk that any client brief undermines the implementation of the Paris Agreement.”   

The DeSmog report also names the individual CEOs “by the Big Oil spend facilitated on their watch.” WPP's former CEO, Mark Read, leads the list at $699 million. Read stepped down last fall, succeeded by current CEO Cindy Rose. Omnicom's John Wren is second-ranked on the list ($566 million). Rounding out the top-5 (respectively) are former IPG CEO Michael Roth ($457 million), Former WPP CEO Martin Sorrell ($362 million) and Havas CEO Yannick Bollore ($230 million). 

The release of the report is timed to WPP’s annual shareholder meeting on May 8. The company declined to comment on the report.  

DeSmog compiled a ranking of ad groups by the estimated volume of oil advertising they've facilitated in the U.S. since 2016. It mapped agency relationships using public sources, including LinkedIn profiles and industry award listings, and then cross-referenced them with ad spend estimates from the market research platform MediaRadar, supplied by the University of Oxford's Climate Litigation Lab.   

Together, the four oil companies spent an estimated $1.5 billion buying U.S. ad space in the decade after Paris, according to the research. More than two-thirds of those ads were made with WPP's support. Behind WPP are the recently merged Omnicom and Interpublic Group. Tokyo-based Dentsu ranks fourth ($255 million), and Paris-based Havas ranks fifth ($230 million).