TL;DR: What Exxon Knew—and Why It Matters Now
- Exxon’s own scientists were warning leadership about climate change by the late 1970s, and later analysis shows the company’s projections were strikingly accurate.
- Publicly, ExxonMobil’s messaging often emphasized “uncertainty,” even as internal work did not support “no warming” or “natural fluctuation” narratives.
- Today, households are absorbing the costs—including rising homeowners insurance premiums and higher nonrenewal rates in high climate‑risk ZIP codes.
ExxonMobil scientists modeled and predicted human-caused global warming decades ago, with projections later shown to be broadly accurate. (Science) Publicly, Exxon’s strategy emphasized “uncertainty,” even as internal work did not support “no warming” narratives. (New York Times) Today, climate risk is contributing to rising homeowners insurance premiums and higher nonrenewal rates in the highest-risk ZIP codes. (US Treasury)
What Exxon Knew—And When
Exxon knew about climate change as early as July 1977.
We know from documented internal briefings, memos, and scientific studies that their scientists warned the company that oil and gas products were causing major climate change impacts—and that they needed to act quickly to reverse course.
Decades before climate change was a mainstream issue, Exxon’s scientific staff and leadership were aware of the risks fossil fuels posed. Research published in Science showed that between 1977 and 2003, Exxon scientists modeled climate change with expert accuracy that matched independent estimates from outside government and academic sources.
As early as the 1950s, oil industry scientists from Humble Oil (a predecessor of ExxonMobil) were connecting fossil fuel burning with increased atmospheric carbon dioxide (CO2) and studying the negative impacts of fossil fuel carbon in the atmosphere and ocean.
It’s not just scientists who were aware—modern investigations show that oil industry leaders were well informed of their scientists’ findings on climate change. Internal documents reveal that leaders knew the potential dangers of global warming, understood that their products were causing it, and were told that they needed to act quickly to prevent climate change from increasing in severity.
Bottom line: ExxonMobil’s internal science was not vague. It was early, detailed, and extremely accurate.
Knowingly Misleading the Public: Exxon’s Response
But instead of prioritizing human health and safety, Exxon lied to the public in order to protect their profits. For decades, they:
- Refused to publicly acknowledge climate change.
- Spent millions on think tanks and PR campaigns to mislead everyday people.
- Lobbied to block progressive climate policy.
Research has shown a massive difference between what Exxon understood internally about climate change and what they were telling the public. In 1988, Exxon’s internal memos show that their official public affairs strategy was to “emphasize the uncertainty in scientific conclusions regarding the potential enhanced greenhouse effect”—despite the fact that their internal scientific studies were crystal-clear about fossil fuel products causing global warming. These internal studies explicitly excluded the possibility of global warming being ‘natural’ (not caused by humans)—and at the same time, Exxon’s public advertising and communications frequently made claims that it was a naturally occurring phenomenon.
More broadly, multiple investigations and document collections describe how parts of the fossil fuel industry—backed by major companies—worked for decades to shape public perception, manufacture doubt, and obstruct action.
This pattern of having internal scientific evidence showing fossil fuels cause climate change while choosing to mislead the public about it is not unique to Exxon. Many other oil companies have followed similar patterns, but Exxon is a key figure with a public, documented track record. If you’re curious about where other oil and gas companies measure up, check out our blog: Which is the Worst Oil Company of Them All?
Decades of Inaction: Impacts on Ordinary People
Now, decades later due to the willful inaction and misleading of oil companies like Exxon, ordinary people are paying the price of the climate crisis through skyrocketing costs.
One of the clearest places this shows up is homeowners insurance.
It’s risky to insure a state on the front lines of climate impacts like wildfires, heat waves, and floods. That’s why rates are rising for millions of homeowners and renters in California.
The U.S. Treasury’s Federal Insurance Office reports that homeowners insurance is getting more expensive and harder to obtain, with nonrenewal rates higher in the highest climate‑risk ZIP codes and premiums meaningfully higher in high‑risk areas.
Between the ongoing loss of insurance options in California, years of rate increases, and costly rebuilding efforts from natural disasters, we’re facing a rapidly escalating affordability crisis driven by climate change.
UCLA’s Luskin California Poll reports that more than 1 in 5 California homeowners are uninsured because of canceled policies and unaffordable premiums. And studies reported in CalMatters shows that when home insurance costs surge, landlords pass those hikes on to renters.
Between 2023 and 2025 State Farm alone received approval for cumulative rate increases totaling 45%, raising average annual premiums by $841.
California’s insurance of last resort, the FAIR Plan, has skyrocketing rates of enrollment—growing 500% from 2018 to 2025.
The loss or unaffordability of coverage makes it harder for buyers and owners to secure and maintain mortgages, which in turn:
- Depresses property values
- Heightens the risk of defaults and foreclosures
- Slows the rate of new development, further exacerbating the state’s critical housing shortage
And it also deeply affects the already stretched housing market in our state. 13% of California real estate agents report that they had deals fall through in 2024 after buyers couldn’t secure affordable home insurance policies.
Affordability Solutions for Fair Share Accountability
It’s common sense: the biggest fossil fuel companies that profited while delaying climate action shouldn’t leave everyone else holding the bag. Evidence is clear that these corporations knowingly drove the climate crisis to a breaking point and misled the public for decades in order to continue profiting at the expense of ordinary people—and it’s not right that everyday Californians are bearing the full cost of climate-driven price spikes.
As insurance markets strain under the climate crisis, insurance affordability is a critical avenue to make billionaire oil corporations pay their fair share and take the pressure off of ordinary people.
That’s where the Affordable Insurance and Recovery Act (SB 982 – Wiener) would have come in. This bill in the California legislature would have helped to make home insurance affordable and available in our state, empowering the Attorney General to take large oil and gas corporations to court and make them pay their fair share to:
- Help make families whole after climate-driven disasters like wildfires.
- Stabilize the state’s insurer of last resort to make insurance available and affordable.
- Support low- and moderate-income property owners with wildfire resilience.
Unfortunately, on April 22, 2026, the California Senate Insurance Committee narrowly failed to pass the Affordable Insurance and Recovery Act and blocked it from moving forward in the 2026 California legislative cycle. Read more about this groundbreaking policy solution and our continued efforts to make insurance affordable in California.
If we’re serious about solving the affordability crisis—starting with the insurance crisis—we need to be serious about making the biggest fossil fuel corporations pay their fair share instead of placing that burden on everyday people.
Sources and Recommended Reading
- Exxon Knew about Climate Change Almost 40 Years Ago | Scientific American
- Assessing ExxonMobil’s global warming projections | Science
- The Climate Deception Dossiers: Internal Fossil Fuel Industry Memos Reveal Decades of Corporate Disinformation (2015)
- Exxon’s Climate Denial History: A Timeline | Greenpeace
- Exxon Scientists Predicted Global Warming, Even as Company Cast Doubts, Study Finds | New York Times
- Radiocarbon Evidence on the Dilution of Atmospheric and Oceanic Carbon by Carbon from Fossil Fuels | Smoke & Fumes
- Early oil industry knowledge of CO2 and global warming | Nature Climate Change
- Home Insurance Kills the Deal for Some California Buyers | Realtor.com
- State Farm wins first-ever emergency rate hike in California – CalMatters
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