The New York Times proclaimed in a recent article that humans caused catastrophic wildfires in California, leading to a large and tragic loss of life. The author seemed to blame these fires on man-made climate change and pointed to evidence of humanity’s negative effect on the environment by citing a peer-reviewed study in a prestigious academic journal. The science is clear, the article argues: Human beings caused one of history’s great tragedies through their careless disregard for the environment.
But the cited study is based on megafauna evidence gathered at La Brea Tar Pits — from 13,000 years ago. According to the NYT author, scientists have “concluded that the disappearance of … large mammals in this region … was linked to rising temperatures and increased fire activity spurred by people.”
The extinction event highlighted in this article happened approximately 12,800 years before the Industrial Revolution began belching supposedly pollutive carbon into our supposedly fragile atmosphere. Nevertheless, the Times article appears to undauntedly equate the past with the present.
According to the report, the authors of the study used a computer model — “similar to the ones that forecast trends in the stock market” — to determine humanity’s role in the fires 13,000 years ago. They allegedly found humans to be the “primary drivers” — both by direct ignition (i.e. campfires that got out of control, and other causes), and by overhunting herbivores, which led to underbrush growth that became fuel for wildfires.
The study itself, recently published and discussed in an essay in Science, “ties together the two leading hypotheses: “human activity and climate change” with fire as the “key mediator.”
The study seems to land on humans as the main cause of these fires, which, in conjunction with a changing climate, led to an environmental “state shift.” The lead author of the referenced study, F. Robin O’Keefe, said, “We implicate humans as being the primary cause of the tipping point.”
The “overkill” theory regarding human blame goes like this: The end of the ice age warmed North America, leading Stone Age humans to migrate in exploration for new resources and lands. The humans, having perfected stone tools for hunting, placed new pressures on populations of herbivores, hunting and removing them from ecosystems reliant on the plant-eaters to keep the underbrush at bay. Then, those same humans let all their fires get out of control, which combined with the warming climate to create a doom loop in which fires got worse, vegetation disappeared, and animals went extinct.
That’s a helluva theory, but it fails to account for a host of variables. Even the essay in Science quotes independent consulting archaeologist Joe Watkins, who worries the recent study places too much weight on the human variable. “There is no real way to specifically link [early] humans to the increase in fires,” he says. “There are alternate possibilities.”
For example, North American glaciers started receding around 14,000 years ago. This really big change to the climate leading to warmer and drier conditions lasted almost 3,000 years and ended 10,000 years ago. New evidence suggests humans came to North America earlier than previously believed — as long as 16,000 years ago or more — meaning they coexisted with their new ecosystem for thousands of years. In light of this, it seems a bit of a stretch to suggest that suddenly, over a relatively short 400-year period, humans lost control of themselves and burned down their environment.
Even O’Keefe, the lead author of the study, admits that “in the past he had been convinced by the overkill hypothesis. ‘This kind of 20th century masculine “we’re going to hunt them to extinction” kind of thing.’”
However, “Then he saw all the data showing people had coexisted with megafauna for thousands of years. ‘I had to unlearn this idea that it was going to be humans’ fault. … It’s more nuanced than that.’”
Watkins noted that dry lightning storms probably contributed to the wildfires. Indeed, lightning is — by a wide margin — the leading cause of fires today, and there’s no reason to believe it wasn’t the leading cause of fires 13,000 years ago. On a different note, some studies have suggested mammoths went extinct far earlier than we previously believed, and that extreme cold, not only extreme heat, can be the cause of mass extinction.
But none of this nuance appears to matter to the New York Times author who seems primarily concerned with how the study relates to climate change today. The article seems to suggest that because humans allegedly caused the mass die-off in Southern California 13,000 years ago, we will do it again — because we always do.
The piece concludes with a quote from a paleoecologist not involved in the study, who said, “What we are seeing today — increasing human pressures combined with and actually causing climate change — is like this lesson from the past on steroids.”
It’s all a classic example of historical “retcon,” or retroactive continuity — which is essentially the creation of a revisionist view of history, revising facts and events we all thought we knew. And thanks to the worldview of the Times reporter, it has even seeped into science reporting, creating a de facto revisionist science.