Investment Arbitration and International Climate Change Law: Revaluing Legitimate Expectations

Investment Arbitration and International Climate Change Law: Revaluing Legitimate Expectations is a carefully argued, and usefully pragmatic book. It speaks to tribunals in their own doctrinal language, supplies an evidentiary theory for integrating ICCL into LE, and respects both the urgency of climate action and the rule of law values of predictability and reliance. The book does a great job in arming both investors and States with principled arguments that are legible to arbitral tribunals and rooted in existing case law. According to ICSID statistics, cases relating to oil, gas, and mining, in addition to electric power and other energy, make up almost half of the cases on its docket, with a steady flow of ECTbased claims.4 However, claiming that investment arbitration is to blame for State climate inaction is a strawman argument.5 It is also true that the distribution of the burdens of our energy transition needs constant attention, and arbitral tribunals have their role to play in this, as long as States agree to it. But tribunals cannot substitute for the political economy of just transition. I recommend the book as a great source of inspiration for what lawyers often engage in: reimagining the law in response to change.— By Bálint Kovács - ICSID Review - Foreign Investment Law Journal 23 July 2026

His book helps explain the paradox of a growing academic interest in a field – the intersection of climate change law and policy and investment arbitration – despite the relatively few actual ISDS disputes crystallised so far. As an arbitration expert, Lehmann seeks to explore how international investment and climate change law can complement one another, aligning with those who view investment arbitration as a potential ally in the climate transition. His study constitutes a valuable and timely contribution that lays a solid foundation for a broader and much-needed discussion on the evolving relationship between international investment law and climate change.— Camille Martini - The Law and Practice of International Courts and Tribunals 24 (20 25) 1–5

With his research, the author makes a significant contribution to the construction of an emerging discipline, and at the same time demonstrates the persistence of the classical, traditional notions of public international law, confronted with the principles of this new branch of law, closely linked to present and future economic development. It is a work of mandatory reference. (translated to English) —Pierre-Jean Thil - Cuadernos de Derecho Transnacional (Octubre 2025), Vol. 17

This book stands out for its theoretical precision and methodological creativity. By summarizing the factual assessment of LEs in energy investment arbitration awards, Dr Lehmann shows how arbitral tribunals could integrate ICCL into IIL, especially into investment arbitration constructively and without undermining the stability of the investment regime. While some normative and institutional questions remain open, the book offers a clear and innovative pathway forward that deserves attention from both scholars and practitioners. It will be of particular interest to scholars, arbitrators, and policymakers working at the intersection of investment protection and climate governance. — Simeng Wang - European Investment Law and Arbitration Review Volume 10, Issue 2, 2025

After reading this book, we must echo Prof. Dr. Klaus Sachs' observation in his foreword that "[i]t is not difficult to predict that this book will soon land on the desk of any practitioner in the field" (page xv). The book (which tellingly begins by quoting the formulation of Kant's categorical imperative) reminds us that we must find ways under international law or otherwise to make sure that the protection of individual rights will not affect ICCL in achieving its monumental goal. — Eduardo Silva – Romero, Cahiers de l'arbitrage 1 juillet 2025

The book’s targeted and well-substantiated analysis, based on Lehmann’s doctoral research, offers a significant and original contribution to the growing literature at the intersection of climate change and investment arbitration. — Camille Martini - The Law & Practice of International Courts and Tribunals – October 2025

The book offers a clear and innovative pathway forward that deserves attention from both scholars and practitioners. It will be of particular interest to scholars, arbitrators, and policymakers working at the intersection of investment protection and climate governance. — Simeng Wang, PhD candidate at Durham Law School - European Investment Law and Arbitration Review Issue 2 -2025

Investment Arbitration and International Climate Change Law: Revaluing Legitimate Expectations, is a valuable contribution to those engaged in the resolution of investor-state disputes in the energy sector. Whether you are an investor, counsel to an investor, a state, counsel to a state, or an arbitrator facing changing climate policies, this book should be added to your library. — Joseph M. Matthews – TDM April 2025