Attribution science and climate change litigation in India

In climate change litigation, attribution science is increasingly being used as an evidentiary tool to ascertain responsibility, accountability, liability, and provide redress the impact on human life and the environment. The Indian judiciary implicitly uses scientific evidence in an unstructured or fragmented manner without it being clearly labelled as attribution science. This current ad-hoc reliance on scientific evidence without an identifiable scale may lead to inconsistencies in judicial outcomes, undermine legal certainty, and hinder the transparent and systematic development of climate jurisprudence. Drawing on the mathematical work of Charles Weiss, we offer an interdisciplinary explanatory climate framework that addresses the uncertainty of science by assembling a scale of legal standards arranged in a hierarchy of levels of increasing certainty familiar to the judiciary and lawyers. The originality of this article lies in extending Charles Weiss ‘standard-of-proof’ scale to address how attribution science integrates within a calibrated language of confidence and likelihood, terms used in the IPCC’s framework (Sixth Assessment Report). Reported Indian cases from the Supreme Court, High Courts and the National Green Tribunal are selected to illustrate levels of scientific certainty or uncertainty and corresponding legal standards of proof constituting acceptable bases for legal decisions in climate change litigation. The adoption of a ‘scientifically legal’ climate lexicon helps increase the precision and rationality regarding the different threshold levels for establishing causation. This article encourages next step thinking within the climate attribution adjudicative process thereby developing context-specific benchmarks that reflect India’s constitutional safeguards, precautionary ethos, and public-interest litigation traditions.