Executive Summary

The proliferation of climate change regulation has resulted in increasing entanglement with investment law. Environmental measures are a significant source of new investment disputes, and as States continue to take steps to curb climate change, the tension between the two fields will grow. Resolving that tension will increasingly require tribunals to grapple with complex evidence concerning scientific justifications for, and efficacy of, environmental regulation.

Investment arbitration decisions to date evince no consistent or coherent framework for the treatment by tribunals of scientific evidence in claims arising out of measures implemented by States under the banner of environmental protections. However, jurisprudence from a select few investor-State decisions, as well as from the WTO and ICJ, potentially chart a course forward.

We advocate consideration of a uniform adoption of a due process-based framework for the assessment of scientific evidence akin to that employed by the tribunal in Methanex Corporation v United States of America. Such a framework would see tribunals eschew any detailed merits assessment of the evidence, focusing instead on the integrity of the process used to generate that evidence.

This framework offers consistency with the roles of international investment law and international investment arbitration, and addresses the significant limitations that encumber tribunals' ability to properly interrogate the "correctness" of the scientific evidence placed before them.

This paper will be part of the OGEL Special Issue on "Climate Litigation and the Energy Sector". More information here www.ogel.org/news.asp?key=750

Previously published in the TDM 5 (2023) Special Issue on International Investment Arbitration - Environmental Protection and Climate Change Issues (Volume 2), September 2023. www.transnational-dispute-management.com/article.asp?key=3028