The science that can name you: An introduction to attribution science for business leaders
For most of corporate history, companies could accept that climate change was real while arguing that no one could trace a specific loss to their specific emissions. A fast-moving scientific field is dismantling that position. Executives and boards need to understand what attribution science is, what it has established and why it matters for them personally.
A question that seemed unanswerable
In 2003, a group of climate scientists posed a question that would define an emerging research discipline: could science ever link an individual organisation's emissions to climate change? At the time, the question seemed almost academic. Climate models could show that human activity in aggregate was warming the planet. They could not, or so it was assumed, trace that warming back to the decisions of a specific company, made in a specific year, producing a specific product. The causal chain from a barrel of oil extracted by a named corporation to a flood that destroyed a named farmer's property seemed far too long, too complex and too diffuse to be established with the precision that legal accountability requires.
Twenty-two years later, researchers at Dartmouth College and Stanford University answered that question. In a study published in Nature in April 2025, Christopher Callahan and Justin Mankin established a peer-reviewed, transparent and reproducible framework that traces the emissions of individual fossil fuel companies through to specific warming outcomes and then to measurable economic losses. Their conclusion, in the paper's own words: 'We argue that the scientific case for climate liability is closed, even if the future of these cases remains an open question.'[1]
What attribution science actually does
Attribution science, sometimes called climate attribution, is the systematic quantification of the influence of specific human activities on specific climate outcomes. It is not a single technique but a family of approaches that has developed rapidly over the past two decades, driven by advances in climate modelling, computational power and the growing body of observational data available to test model outputs against reality.
At its most fundamental level, attribution science works by comparison. Researchers build two versions of the climate: one that reflects the world as it actually is, with the greenhouse gas concentrations that human activity has produced and one that reflects a counterfactual world in which a specific source of emissions did not exist. By running these two scenarios through validated climate models and comparing their outputs, researchers can quantify how much of an observed change in temperature, precipitation, sea level or extreme weather frequency is attributable to that specific emission source.
This approach has been applied at scales ranging from the global – attributing a share of total warming to all human activity – down to the corporate. The critical breakthrough in the last decade has been the ability to simulate emissions directly rather than relying on atmospheric concentration measurements. Atmospheric greenhouse gas concentrations are a common pool – they accumulate from all sources worldwide and cannot easily be traced back to individual contributors. Direct emissions simulation allows researchers to model what would have happened to the atmosphere if a specific company's historical output had not occurred. The difference between that counterfactual and reality is that company's attribution.
The Carbon Majors framework
The corporate-level application of attribution science relies in significant part on the Carbon Majors Database, maintained by InfluenceMap. This database traces cumulative historical emissions from 1854 through 2023 to 180 named industrial producers – including state-owned enterprises, investor-owned companies and nation-state producers – accounting in total for 1,388 GtCO₂e of emissions over that period. By establishing each company's share of total cumulative industrial emissions, the database provides the denominators that attribution calculations require.[2]
The significance of the Carbon Majors framework for corporate liability is that it turns what was previously a diffuse, shared responsibility into a quantified, company-specific one. A company that contributed 0.47% of total global industrial emissions since the industrial era is not responsible for all of climate change. But it is responsible, in principle, for 0.47% of the damages that climate change has caused. That is the logic that Peruvian farmer Saúl Luciano Lliuya applied in his lawsuit against RWE – and that a German court accepted as a valid legal basis in 2025, even though the specific claim ultimately failed on evidentiary grounds.
What the 2025 Nature study established
The Callahan and Mankin study in Nature represented a significant methodological advance because it completed the attribution chain end-to-end, for the first time, at the corporate scale. Using Scope 1 and Scope 3 emissions data from major fossil fuel companies, the study applied peer-reviewed attribution methods and advances in empirical climate economics to estimate the economic losses from extreme heat attributable to the emissions of individual companies. The results were significant in scale: extreme heat linked to just 111 companies cost the global economy an estimated $28 trillion from 1991 to 2020. The five highest-emitting firms accounted for $9 trillion of that total. The highest-emitting investor-owned company – Chevron – may be responsible for between $791 billion and $3.6 trillion in heat-related losses over the same period.[1]
These numbers are large enough to seem almost abstract. The more important point for executives and boards is what the methodology establishes: that the entire chain from a company's reported emissions to a specific category of economic loss in a specific region of the world can now be quantified, peer-reviewed and presented in court as mainstream scientific evidence. The methodology uses established, published methods at each step. It is transparent and reproducible. It has been published in one of the world's most rigorous scientific journals. It is not advocacy science. It is the kind of evidence that courts admit and that opposing experts struggle to rebut.
The current limits of the science – and why they are shrinking
It is important to be precise about what attribution science can and cannot yet do. The 2025 Nature study addresses extreme heat outcomes – a category of climate impact that is, as the authors note, most directly and cleanly linked to temperature increase, which in turn is most directly linked to greenhouse gas concentrations. Other categories of climate impact – flooding, hurricanes, wildfires, sea level rise – involve more complex causal chains and currently require more elaborate scientific modelling to attribute to specific emitters.
Researchers at Mongabay have reported that the authors of the Nature study anticipate that 'in a few years, researchers will develop models for evaluating contributing causes of other extreme weather events like hurricanes, flooding, sea level rise and wildfires that can be easily ported into our step-by-step framework.' The scientific frontier is not static. The attribution of flooding, drought and biodiversity loss to specific corporate emitters is an active area of research and the direction of travel is toward greater specificity, not less.[3]
For executives and boards, the implication is clear: the scientific tools available to plaintiffs, prosecutors and regulators are becoming more granular and more capable with each passing year. The question is not whether attribution science will reach the level of specificity required to support corporate liability at scale. It is when – and whether your organisation is building the governance infrastructure to manage that exposure before it becomes acute.
References
[1] Callahan, C.W. and Mankin, J.S., 'Carbon majors and the scientific case for climate liability', Nature, vol. 640, pp. 893–901 (April 2025). DOI: 10.1038/s41586-025-08751-3. https://www.nature.com/articles/s41586-025-08751-3
[2] InfluenceMap, 'Carbon Majors: 2023 Data Update'. https://influencemap.org/briefing/The-Carbon-Majors-Database-2023-Update-31397
[3] Mongabay, 'Science Lays Out Framework to Assess Climate Liability of Fossil Fuel Majors' (9 May 2025). https://news.mongabay.com/2025/05/science-lays-out-framework-to-assess-climate-liability-of-fossil-fuel-majors/