regarding the existence, causation, and severity of climate risks associated with fossil fuel production and use. To the contrary, Carbon Majors companies engaged in active, wellresourced, and ongoing efforts to undermine public confidence in climate science, public concern about climate risks, and public support for action to address those risks. By the 1990s, despite acknowledging the consensus surrounding climate change internally, many of the Carbon Majors were coordinating, either directly or through industry groups, to spread disinformation and sow doubt about the certainty and legitimacy of climate science. 340 These campaigns persisted through the 2000s341 and into the current decade,342 and are likely continuing at present. 343 More fundamentally, any assessment of the Carbon Majors’ actions and omissions with respect to climate change must take into account that more than half of atmospheric greenhouse gases have been emitted since 1988, by which point all or nearly all Carbon Majors companies as experts in their products - knew or should have known the potential risks of those products. C. Causation (Plan B) Plan B offered the following additional comments with respect to the question of causation. The standard test for causation in tort law is the “but for” test, i.e. can the claimant prove that the alleged damage would not have occurred but for the defendant's acts or omissions? The strict application of this test would present a claimant with two major hurdles in the context of climate change litigation: 1) Can the claimant show that damage would not have occurred but for man-made climate change? If yes, 2) Can they show that the relevant degree of climate change would not have occurred but for the actions/omissions of the defendant? The law, however, is concerned with both substantive justice and the fair allocation of cost. Where rigid application of the “but for” test is inconsistent with these objectives, courts around the world have adopted more flexible approaches. In circumstances of scientific complexity, for example, or where multiple causes are present, courts have adopted alternative tests, such as whether a defendant’s acts or omissions made a material contribution to the harm, or materially increased the risk of the harm occurring. More specifically, in the context of pollution from different sources, they have developed the commingled product theory of causation. Such approaches translate well to the context of climate accountability. Demonstrating that the actions of a particular defendant have, for example, “materially increased the risk” of climate change damage occurring has been made significantly easier by: i) developments in the science allowing for the probabilistic attribution of specific climatic patterns and weather events to climate change; 340 Id. at pgs. 13-14. Id. at pgs. 14-15. 342 Id. at pgs. 15-16. 343 See CIEL, SMOKE AND FUMES: THE LEGAL AND EVIDENTIARY BASIS FOR HOLDING OIL COMPANIES ACCOUNTABLE FOR CLIMATE CHANGE, supra note 323, at 18. 341 71