From lead to climate change: a long tradition of denialism

Despite the overwhelming scientific evidence (see previous ASO blogs on the subject, like the ones found here and here), climate change is still regularly denied by a rather large proportion of the U.S. population. Much of this denial may be traced back to certain groups and interests that benefit from the government and other players not acting on correcting the problem. However, the phenomena is not the first issue that has been targeted by campaigns of denial: the science behind the detrimental effects of tobacco smoke, DDT, and acid rain has also been questioned by different groups and interests. One of the earliest examples of this focuses on the work to get lead out of gasoline.

Geochemist to activist

Clair Patterson was a well-known and accomplished geochemist. In 1953, he presented on a five-year study to calculate the age of the Earth using lead isotopes; his estimate of 4.55 billion years was far more accurate than any calculated up until that point and has remained largely unchanged since then. However, it was during this study that Patterson found that lead contamination in the laboratory and environment was ubiquitous; he decided to focus his work on determining how much of this contamination was natural and how much was manmade.

Patterson sampled ice cores from Greenland and Antarctica, microscopic plankton found in ocean sediments, and the 1600-year-old bones of pre-Columbian humans – things that should not have been exposed to the modern, widespread use of lead. All of the evidence pointed to the fact that modern-day, industrial societies had increased levels of atmospheric lead by about 1000 times. Much of this has been linked to the 7 million tons of lead that were burned in gasoline during the 20th century, which was added to reduce engine ‘knocking’. Unfortunately, lead is a potent neurotoxin and can lead to numerous, serious health problems: learning and behavior disorders, organ and nervous system damage, and cancer. After discovering that gasoline was one of the major causes of lead contamination in the atmosphere, Patterson turned his attentions to getting lead out of gasoline.


Lead began to be added to gasoline in 1921 as a way to reduce engine ‘knocking’. Source: Wikimedia Commons

Corporate lobbyists, however, were not pleased with Patterson’s new focus: by the 1930s, lead was in 80% of the 12 billion gallons of gas sold, which lead to an annual gross of $300 million. In order to maintain these profits, there were attempts to silence and discredit his work: Patterson lost many of his research contracts (which were tied to the lead industry), and there was pressure placed on the chairman of his department at Cal Tech to fire him. Corporations also utilized their own scientists and experts (namely Robert Kehoe) to criticize Patterson’s work and raise confusion about the dangers of lead.

Nevertheless, Patterson persisted in his pursuit. His work helped provide a basis for the EPA mandate of installing catalytic converters, which reduce exhaust pollution but are damaged by lead, on all car models in 1975. This immediately created the demand for unleaded gas. Lead was finally removed from all standard gas in the U.S. in 1986. By the late 1990s, American lead blood levels had dropped by about 80% since the late 1970s.

Lessons for today

As mentioned at the beginning of this blog, climate change skepticism seems to be the latest incarnation of science denial by certain groups. The same tactics of discrediting scientists, employing dissenting experts, and creating confusion and uncertainty have been used countless times to protect some status quo. For instance, a few months before the historic Paris Agreement, a largely missed investigation suggested that ExxonMobil, the world’s largest oil and gas company, was aware of and understood the science of climate change as early as 1977 – about 11 years before it entered the public consciousness. By the late 1980s, though, the corporation had already become a leader in campaigns that denied the phenomena and questioned the science behind climate change.
The parallels between lead pollution and climate change are readily apparent and much could be learned from the tactics used in past denialism campaigns. Maybe most importantly, understanding the sources and funding of denialism can help separate the science from confusion.

About the Author

A transplant from Virginia (Hoos!), Greg Evans is a graduate student in the Plant Biology department at the University of Georgia studying defense tradeoffs in morning glories. When he’s not tangled up in weeds, Greg enjoys Ultimate Frisbee, bowling, and board games. He can be reached at More from Greg Evans