Adv. María José Alarcón Santillán, SJD (cand) (GW Law), LL.M. (Duke Law), Dual LL.M. in Corporate and EU Law (IE), LLB International Law (UNAV), LLB (U Hemisferios), is an international lawyer and scholar based in London specializing in public international law, state responsibility, climate change law and investment arbitration. She holds bar admissions in New York, Spain, and Ecuador, and is a Solicitor of England and Wales. She is currently Regional Co-leader for International Courts and Tribunals at the Columbia Sabin Center for Climate Change Law and serves as Counsel for the IUCN in the Advisory Opinion for Climate Change before the International Court of Justice. Her academic engagements include contributions as Associate Professor of International Environmental Law and research roles at Leiden University, Duke University, and assistant editor for the Kluwer Arbitration Blog. She is currently an Assistant Editor for the Opinio Juris Blog and conducts research for the ASIL Task Force on Investor-State Dispute Settlement (ISDS) and Climate Change.

Professionally, she has advised states in disputes before ICSID, ITLOS, PCA, and the ICJ and has published extensively on investment arbitration, investment treaty reform and climate litigation. Her work blends practice and academia to address legal challenges at the intersection of international dispute resolution, sustainability and human rights. She is committed to advancing legal scholarship and policy in support of global climate justice.