The Flawed Study Underpinning the “Attribution Science” Lawsuits

In September 2017, the cities of Oakland and San Francisco, led by trial attorney Matt Pawa, filed lawsuits against five of the world’s largest oil companies for damages related to climate change, which they say will affect “the people and property” of Oakland and San Francisco.


The “public nuisance” suits, filed against BP, Chevron, ConocoPhillips, ExxonMobil, and Royal Dutch Shell, are seeking billions of dollars “to pay for climate change adaptation programs, which would include the construction of sea walls and raising low-lying buildings exposed to rising tides.”

This week, Mayor Bill De Blasio announced that New York City is also suing the same five oil companies demanding they pay for the cost of protecting the city from the "existential threat" of climate change, bringing the number of these suits to eight.

At the heart of this coordinated litigious assault on the oil and gas industries is the Carbon Majors report created by Richard Heede, co-founder of the Climate Accountability Institute, and host of the now-infamous 2012 La Jolla conference, a gathering of two dozen nationally recognized environmental activists, academics, and trial lawyers who met to explore “whether we might use the lessons from tobacco litigation to address climate change.”

The Climate Majors report—which was updated and re-released by Heede and other climate-change activists in 2017—purports to assign a specific percentage of the cause of climate change to individual companies. “What Heede did helps assign blame,” Pawa said. “It’s a list with names and numbers. It individualizes responsibility in a way that had not been done before.”

But the scientific foundation the trial lawyers hoped to build their dream cases on is starting to show cracks. In fact, the “science” is so shaky that even the activists and climate scientists themselves are criticizing it. The following comes from the anti-industry publication Climate Liability News:

  • Kevin Trenberth, a climatologist at the National Center for Atmospheric Research in Boulder, Colo., said the study is flawed because the researchers did not test the climate model they used on independent data. The model may also be overly simplistic, leading to errors, he said. “For example, it uses global mean surface temperature but has no hydrological cycle, no land-versus-ocean, no Arctic amplification and no validation,” Trenberth said. “It does not provide any information about how good any of the relationships are that the model is based on and how stable they are over time.”
  • Michael Burger, executive director of the Sabin Center for Climate Change Law at Columbia University, warned that the study itself does not determine any company’s legal liability ... “The new [Heede] study makes a contribution to that body of literature [on attribution science], but it is not determinative in and of itself of any company’s or companies’ liability.”

And even a number of climate scientists who attended the 2012 La Jolla conference where Heede first unveiled his research expressed doubts about the concept.

Several of the climate scientists at the meeting addressed the scientific challenges involved in attributing specific environmental effects to anthropogenic climate change … Claudia Tebaldi, a climate scientist at Climate Central, emphasized the problem of confounding factors: “We are far from being able to say anything definitive because the signal is so often overwhelmed by noise.”

Perhaps the most damning comment about climate change attribution science comes from a September 2017 report from George Washington University entitled Science in Litigation, the third branch of U.S. climate policy, which “systematically investigate[d] the role of science, and climate science in particular, in federal and state litigation in the United States”:

Plaintiffs thus far have been unable to muster scientific support that establishes a causal link between a particular source or group of sources of GHG emissions and the climate-related harms they have suffered …

It is likely that plaintiffs in tort actions will find it difficult based on currently available science to trace alleged climate-related personal injuries or property damage to the actions of particular defendants. This may change as climate science continues to develop (such as science that could “fingerprint” the harms linked to specific GHG emissions), but the likelihood that this shift will occur in the near term is small.

And that’s what the folks on Heede’s side are saying. One can only imagine what flaws can be uncovered once Heede’s research and methodology are scrutinized by a team of impartial researchers.