On January 9, as deadly wildfires raged across the Los Angeles area, destroying thousands of structures and displacing tens of thousands of residents, Columbia University hosted the first day of its Attribution Science and Climate Law Conference. Co-organized by the Sabin Center for Climate Change Law and the Columbia Climate School, the conference brought together scientists, legal experts, policymakers and advocates to explore how advancements in climate attribution science can shape litigation, policy and governance.
Attribution science is a rapidly evolving field that aims to explain how human-induced climate change intensifies and influences the frequency of extreme weather events. The destruction unfolding in California offers yet another reminder of the urgency of these discussions, and the critical need for science-driven legal and policy solutions to the climate crisis.
Kicking off the conference, Michael Burger, executive director of the Sabin Center, reflected on the genesis of the event. “Eight years ago, in the wake of Donald Trump’s election, the seeds of this collaboration were planted,” he said. Burger recounted how his discussions with climate scientist and professor Radley Horton and legal scholar Jessica Wentz inspired an interdisciplinary approach to understanding attribution science’s potential for informing legal frameworks.
Burger highlighted the urgent stakes of the moment, marked by environmental rollbacks and climate change’s accelerating impacts around the world. “This field has grown from niche to necessity,” he said, citing the increasing reliance on attribution research in courts—from the International Court of Justice to national jurisdictions—and its critical role in corporate accountability.
Understanding Attribution Science
Rather than pinpointing causation, attribution science raises critical questions about the extent to which climate change amplifies the severity or likelihood of events like hurricanes, heat waves and droughts. For example, one of the first major studies in attribution science analyzed the European heat wave of 2003, linking human activities to an increased probability of the devastating event.
By comparing observed weather patterns with simulations of a world untouched by human-induced warming, scientists are uncovering the fingerprints of climate change with increasing precision. While natural variability continues to play a role, attribution science highlights how the climate crisis exacerbates events that were once rare, making them more frequent and more destructive.
Horton, a professor at the Columbia Climate School, introduced the morning session, spotlighting the legacy and contributions of Ben Santer and Gavin Schmidt, whose work was seminal in detecting and attributing human influence on climate systems.
Santer pioneered the field of climate “fingerprinting,” tracing the evolution of attribution science from the cautious conclusions of the first Intergovernmental Panel on Climate Change (IPCC) report in 1990 to today’s unequivocal evidence linking human activities to climate change.
“By 2013, we moved from ‘very likely’ to ‘extremely likely,’ and now to ‘unequivocal’—human fingerprints are all over the climate system,” Santer told the audience.
Meanwhile, Schmidt, director of NASA’s Goddard Institute for Space Studies, provided a broader lens on attribution science. “Detection identifies change; attribution explains causation,” he said. He explained how models, data and physical coherence across variables—such as temperature, precipitation and sea-level rise—enable scientists to attribute specific impacts to human activities with increasing accuracy.
Providing Legal Context
The afternoon sessions explored attribution science in legal contexts, and how it is used to secure justice and accountability for climate impacts. In the panel on government obligations and fundamental rights, moderated by Maria Antonia Tigre of the Sabin Center, speakers shared global perspectives on climate litigation.
Andrea Rodgers, of Our Children’s Trust, highlighted youth-led cases in the United States. In Montana, youth plaintiffs successfully argued that the state’s failure to address climate change violated their constitutional rights.
“Courts often dismiss climate change as too big to address,” Rodgers said, “but in Montana, the judiciary affirmed that every ton of emissions matters.”
Dennis van Berkel, legal counsel for the Urgenda Foundation, shared insights from Europe and South Korea, saying that courts are increasingly requiring governments to quantify their “fair share” of emissions reductions under frameworks like the Paris Agreement.
Pooven Moodley, a climate justice advocate, discussed the important interplay of indigenous wisdom and scientific evidence, describing the landmark case in Ecuador, where the Sarayaku people successfully argued for the forest’s recognition as a “living entity.”
“[Legal cases] are starting to bring human rights and the environment together,” he said. “This is the next frontier, and many of us are involved in pushing the legal boundaries even further.”
Jason Smerdon, a professor of climate at the Columbia Climate School, addressed the challenges of attributing drought to human activities, particularly in regions like the American Southwest. He highlighted the difficulty of defining droughts in a world where baseline conditions are shifting due to long-term aridification trends.
“The signal in the Southwest is much more of an aridification signal than it is a discrete event. We’re going to have wet periods and drier periods, but the overall trajectory is projected to get much drier over time. How we characterize these discrete events when the baseline is changing is something that’s challenging scientifically—and legally,” Smerdon said.
Integrating Science and Law
The second day of the conference emphasized challenges of integrating scientific evidence into legal frameworks.
Burger opened the session with questions about the scientific and legal challenges of integrating attribution science into the courtroom, noting the difficulty of finding studies directly relevant to litigation.
In response, Nauê Bernardo Pinheiro de Azevedo, a political scientist, highlighted two key obstacles in Brazil: misinformation and the country’s ambiguous legal framework.
Aisha Saad, associate professor at Georgetown University Law Center, also underscored the role of judicial education in bridging gaps.
“There will always be bias and presumptions of politicization of climate science in popular perception. While unavoidable, it can be mitigated. IPCC reports, for example, provide an edge in the climate context, offering credibility and depth,” she said.
Attributing Impacts to Specific Emitters
Christopher Callahan, an Earth system scientist and postdoc at Stanford, explored the challenges of linking specific fossil fuel emitters to measurable climate damages, citing examples like the 2021 Pacific Northwest heatwave, which led to a lawsuit brought by Multnomah County, Oregon, against major fossil fuel companies.
“The heat dome was a direct and foreseeable result of the defendants’ actions,” Callahan said, emphasizing the causal chain between emissions and economic harm. His work, leveraging reduced-complexity climate models and pattern scaling, demonstrated how localized hazards like extreme heat can be directly linked to global temperature changes driven by specific emitters.
“The damage associated with a given change in extreme heat is higher in the tropics. The hotter you are, the more damage you suffer from a given heatwave,” Callahan said, pointing out that emitters like Saudi Aramco and Gazprom top the list of contributors to these impacts.
His analysis reveals the disproportionate burden borne by vulnerable regions, where losses exceed 1% of GDP over 30 years. Furthermore, he cautioned how the climate community misses many impacts.
“We are just looking at extreme heat in our work and missing floods, hurricanes and wildfires like the catastrophic ones in L.A. this week. Any non-market impact will not be counted in our GDP growth-focused calculations,” he said.
Marshall Burke, an associate professor at Stanford, added: “We no longer need to argue about whether we can make a link between specific emitters and certain impacts.” However, determining the scale of these impacts remains complex, requiring a mix of robust statistical models and researcher choices, he said.
Both Callahan and Burke emphasized the long-term nature of climate impacts, with Burke warning: “For a ton emitted in 1990, only about one-fifth of the damage has occurred by 2020. Four-fifths are still ahead of us.”
In a final reflective session, panelists called for collective action and emphasized the synergy between diverse forms of knowledge. “Indigenous knowledge, when paired with attribution science, creates powerful legal narratives that challenge corporate and governmental inaction,” said Moodley.
Vishal (Vishy) Manve is a recent graduate of Columbia Climate School and works at the intersection of policy, sustainability and climate communications.
