Ten years since the world learned #ExxonKnew, accountability marches forward.

This fall marks 10 years since the world first learned that Exxon knew as early as the 1970s that its fossil fuel business would help fuel a climate crisis — but purposefully deceived the public to block action and protect their profits. The so-called #ExxonKnew investigations and reports have since led to dozens of lawsuits, Congressional hearings, and scientific studies seeking to shine further light on Big Oil’s climate deception and hold the fossil fuel industry accountable. 

The revelation that Exxon and other Big Oil companies knew better when they lied to the public about the harm of their products was made possible by teams of investigative reporters with Inside Climate News, the Los Angeles Times and Columbia Journalism School. Beginning in September 2015, those outlets published a series of bombshell stories revealing that Exxon’s own scientists warned executives as early as 1977 that the burning of fossil fuels was heating the planet, that this heating could lead to “potentially catastrophic events” (1982) and the world had “a time window of five to ten years before the need for hard decisions regarding changes in energy strategies might become critical” (1978). Instead of warning the public, Exxon and other oil giants internally decided to “emphasize the uncertainty in scientific conclusions” (1988), then executed a decades-long campaign of climate deception, while taking steps to protect their own infrastructure from rising seas and other climate harms they knew their core business would make worse.

In the decade following the first #ExxonKnew revelations, Exxon and other Big Oil companies have faced growing scrutiny and efforts to hold them accountable, including:

• Ongoing lawsuits from 10 U.S. states and dozens of communities that seek to hold the companies accountable for their deception and make them pay for the damage they’ve caused. Many of these cases are now advancing toward discovery and trial, leading the oil industry to lobby Congress for sweeping legal protections. As of September 2025, nearly 30 percent of the US population is represented in one of these lawsuits.
• Multiple congressional hearings and investigations that forced the CEOs of ExxonMobil and other oil giants to testify under oath, produced further evidence of industry deception through subpoenas, and generated calls for the U.S. Justice Department to launch its own investigation into the fossil fuel industry.
• Peer-reviewed scientific studies that have confirmed the accuracy of Exxon’s internal climate projections and concluded the oil giant’s deception campaigns mirrored those by Big Tobacco. 
• Major documentaries, podcasts, books, and other reporters have built on the first #ExxonKnew investigations to further expose the fossil fuel industry’s past and ongoing deceit.    

Just as Big Oil’s internal studies predicted, the past decade has seen a rapid intensification of climate-driven extreme weather events, including worsening hurricanes, floods, droughts, and wildfires. The United States is now spending close to a trillion dollars a year on damages linked to climate change — costs that are straining government budgets and increasing the cost of home insurance for Americans across the country.

Throughout fall 2025, CCI will be revisiting the original #ExxonKnew revelations from 2015, the progress toward accountability made over the last 10 years, and the ongoing fights to make sure Big Oil companies pay for the harms they knowingly caused. 

Read some of the original 2015 “Exxon Knew” investigations below:

Inside Climate News, “Exxon: The Road Not Taken” — a nine-part investigation that was a finalist for the Pulitzer Prize for Public Service in 2016.   

• Exxon’s Own Research Confirmed Fossil Fuels’ Role in Global Warming Decades Ago (September 16, 2015) 
• Exxon Believed Deep Dive Into Climate Research Would Protect Its Business (September 17, 2015) 
• Exxon Confirmed Global Warming Consensus in 1982 with In-House Climate Models (September 22, 2015) 
• Exxon’s Business Ambition Collided with Climate Change Under a Distant Sea (October 8, 2015) 
• Highlighting the Allure of Synfuels, Exxon Played Down the Climate Risks (October 8, 2015) 
• Exxon’s Uncertainty Campaign in Black and White (October 22, 2015) 
• Exxon Made Deep Cuts in Climate Research Budget in the 1980s (November 25, 2015) 
• More Exxon Documents Show How Much It Knew About Climate 35 Years Ago (December 1, 2015) 
• Exxon’s Oil Industry Peers Knew About Climate Dangers in the 1970s, Too (December 22, 2015) 

The Los Angeles Times and the Energy and Environmental Reporting Project at Columbia University’s Graduate School of Journalism:

• Special Report: What Exxon knew about global warming’s impact on the Arctic (October 10, 2015) 
• What Exxon knew about the Earth's melting Arctic (October 9, 2015) 
• How Exxon went from leader to skeptic on climate change research (October 23, 2015) 
• Big Oil braced for global warming while it fought regulations (December 31, 2015)