Robert Percival

Robert F. Stanton Professor of Law and
Director, Environmental Law Program




(410) 706-8030


(410) 706-2184

Photo of Robert Percival


  • BA, 1972, Macalester College
  • MA, 1978, JD, 1978, Stanford University

Professor Robert Percival joined the faculty in 1987 after serving as senior attorney for the Environmental Defense Fund. While in law school, he served as managing editor of the Stanford Law Review and was named the Nathan Abbott Scholar for graduating first in his class. Professor Percival served as a law clerk for Judge Shirley M. Hufstedler of the U.S. Court of Appeals for the Ninth Circuit and for U.S. Supreme Court Justice Byron R. White. He also served as a special assistant to the first U.S. Secretary of Education.

Professor Percival is internationally recognized as a leading scholar and teacher in environmental law. Since 1992 he has been the principal author of the most widely used casebook in environmental law in the U.S., Environmental Regulation: Law, Science & Policy, now in its ninth edition ( He is the author of more than 100 publications on topics that include environmental law, federalism, presidential powers, regulatory policy, and legal history. Professor Percival taught as a visiting professor of law at Harvard Law School in 2000 and 2009 and at Georgetown University Law Center in 2005 and 2011. He received the University System of Maryland Board of Regents’ Faculty Award for Collaborative Teaching in 2005, and in 2007 he was named the University of Maryland, Baltimore Teacher of the Year. In 2014, he received the Senior Distinguished Environmental Law Education Award from the IUCN Academy of Environmental Law in recognition of his outstanding teaching and contributions to the field of environmental law ( In 2019, he received the award for Distinguished Achievement in Environmental Law and Policy from the American Bar Association’s Section on Environment, Energy and Resources Law.

Professor Percival has taught Environmental Law, Global Environmental Law, Constitutional Law, Administrative Law, Torts and Toxic Torts. In 2022 the University of Maryland named him a Distinguished University Professor, the highest appointment bestowed on a tenured university professor.

During the spring semester 2008 Professor Percival taught as a J. William Fulbright Distinguished Lecturer at the China University of Political Science and Law in Beijing. In 1994, he taught as a Fulbright scholar at Comenius University Law School in Slovakia. Professor Percival is a highly popular guest lecturer who has given hundreds of guest lectures, paper presentations, and workshops in 36 countries on six continents. In 2009, he represented the U.S. Department of State on a lecture tour of China. He has delivered guest lectures at 50 U.S. academic institutions, at 32 Chinese universities and before numerous professional associations and government agencies. He has served as the Natural Resource Law Institute Distinguished Visitor at Lewis & Clark College of Law, as a visiting professor of law at the University of Chile where he helped establish South America's first environmental law clinic, and as a high-level visiting foreign expert at Shanghai Jiaotong University’s KoGuan Law School. He has taught summer courses at Shandong University, Vermont Law School, the University of British Columbia, and the University of Aberdeen in Scotland.

Professor Percival has played a leading role in conceptualizing the field of global environmental law. His website and blog on this subject are at Professor Percival has led more than a dozen environmental law student field trips to China, the Middle East, and Africa. He is a member of the IUCN World Commission on Environmental Law and one of the founding members of the IUCN Academy of Environmental Law. In 2009, he delivered Pace Law School's Lloyd K. Garrison Lecture. In 2015, he delivered the Wallace Stegner Lecture at the University of Utah’s S.J. Quinney College of Law, and in 2016, he delivered the Distinguished Environmental Lecture at Florida State University College of Law.

Professor Percival is a member of the board of regents of the American College of Environmental Lawyers. He has served on the board of directors of the Environmental Law Institute and as co-chair of the steering committee of the D.C. Bar's Section on Environmental, Energy and Natural Resources Law. He is an elected member of the American Law Institute, and the American College of Environmental Lawyers, and the National Committee on U.S./China Relations. He has served as the contributing editor for Environment and Natural Resources for the Federal Circuit Bar Journal, as a special master for the U.S. District Court of Maryland, and as a member of the state of Maryland's Environmental Restoration and Development Task Force.


Environmental Law: 2023-24 Statutory and Case Supplement (2023).

Environmental Regulation: Law, Science & Policy (1992; 2d ed. 1996; 3d ed. 2000; 4th ed., 2003; 5th ed. 2006; 6th ed. 2009; 7th ed. 2013, 8th ed. 2018, 9th ed. 2021) (with others). Abstract

Environmental Law: Statutory and Case Supplement 2021-22 (2021).

Comparative and Global Environmental Law and Policy (2019) (with T. Yang, A. Telesetsky, and L. Harmon-Walker). Abstract

Environmental Law: Statutory and Case Supplement 2017-18 (2017) (with Christopher H. Schroeder). Abstract

Against All Odds: How America's Century-Old Quest for Clean Air May Spur a New Era of Global Environmental Cooperation (2016). Abstract

Environmental Law: 2016-2017 Case and Statutory Supplement (2016) (with Christopher H. Schroeder).

Environmental Law: Statutory and Case Supplement (2015-2016) (with Christopher H. Schroeder). Abstract

U.S. Environmental Law (Law Press of China 2014) (trans. under supervision of Zhao Huiyu).

Editor, Global Environmental Law at a Crossroads (2014) (with Jolene Lin and William Piermattei). Abstract

Editor, Law and the Environment: A Multidisciplinary Reader (1997) (with Dorothy C. Alevizatos).

The Roots of Justice: Crime and Punishment in Alameda County, California, 1870-1910 (1981) (with Lawrence M. Friedman).

Book Chapters

International Responsibility and Liability for Environmental Harm, in Routledge Handbook of International Environmental Law (Erika J. Techera, Jade Lindley, Karen N. Scott & Anastasia Telesetsky eds., 2d ed. 2021).

United States, Yearbook of International Environmental Law (2021),

Getting the Lead Out: The Phase-Out of Gasoline Lead Additives--A Global Environmental Success Story, in The Impact of Environmental Law: Stories of the World We Want 8 (Rose-Liza Eisma-Osorio, Elizabeth A. Kirk and Jessica Steinberg Albin eds., 2020).

Transnational Litigation: What Can We Learn from Chevron-Ecuador?, in Research Handbook on Transnational Environmental Law 318 (Veerle Heyvaert & Leslie-Anne Duvic-Paoli eds., 2020).

The Climate Crisis and Constitutional Democracies, in Constitutional Democracy in Crisis? (Mark Graber, Sanford Levinson, and Mark Tushnet eds., 2018).

Environmental Law, in Oxford Bibliographies in Public Health (2017).

International Environmental Law and the United States: 2016, in the Oxford Yearbook of International Law (2017).

Risk, Uncertainty and Precaution: Lessons from the History of US Environmental Law, in Trade and the Environment: The European Union Put to the Test (Marjolein B.A. van Asselt et al. eds., 2014). Abstract

The Globalization of Enivronmental Law, in International Environmental Law: The Practitioner's Guide to the Laws of the Planet (Roger R. Martella Jr. & J. Brett Grosko eds., 2014).

Human Rights and the Evolution of Global Environmental Law, in 2 Economic, Social and Cultural Rights 1 (Subhram Rajkhowa & Stuti Deka eds., 2013). Abstract

International Responsibility and Liability for Environmental Harm, in Routledge Handbook of International Environmental Law 681 (Shawkat Alam et al. eds., 2012). Abstract

Law, Society and the Environment, in Law, Society and History: Themes in the Legal Sociology and Legal History of Lawrence M. Friedman (Robert W. Gordon & Morton J. Horowitz eds., 2011).

La Responsabilidad por Daño Ambiental Global y la Evolución en las Relaciones entre el Derecho Público y Privado (Liability for Global Environmental Damage and the Evolution in the Relationship Between Public and Private Law), in Derecho Ambiental en Tiempos de Reformas (Environmental Law in Times of Reform) 99 (V. Duran Medina et al. eds., 2010). Abstract

El Surgimiento del Derecho Ambiental Global (The Emergence of Global Environmental Law), in Desarrollo Sustentable: Gobernanza y Derecho 11 (V. Duran, S. Montenegro & P. Moraga eds., 2008) (translation into Spanish by Ada I. Diaz-Hernandez). Abstract

Resolucion de Conflictos Ambientales: Lecciones Aprendidas de la Historia de la Contaminacion de las Fundiciones de Minerales, in Prevencion y Solucion de Conflictos Ambientales Vias Administrativas, Jurisdiccionales y Alternativas 399 (2004).

Global Environmental Accountability: The Missing Link in the Pursuit of Sustainable Development?, in The Moral Austerity of Environmental Decision Making: Sustainability, Democracy and Normative Argument in Policy and Law (J. M. Gilroy & J. Bowersox, eds. 2002).

Water Pollution Control: Lessons from Transnational Experience, in Derecho Del Medio Ambiente Congreso Internacional 273 (1998).

Restoring Regulatory Policy to Serve the Public Interest, in Winning America: Ideas and Leadership for the 1990s, at 48 (Marcus Raskin & Chester Hartman eds., 1988).

The Organometals: Impact of Accidental Exposure and Experimental Data on Regulatory Policy, in Neurotoxicants and Neurobiological Function: Effects of Organoheavy Metals 328 (Hugh A. Tilson & Sheldon B. Sparber eds., 1987) (with Ellen K. Silbergeld).

Conservation and Renewable Energy Sources as Supply Alternatives for New York’s Electric Utilities, in The Future of Electrical Energy: A Regional Perspective of an Industry in Transition 126 (Saltzman & Schuler eds., 1986).


The Shadow Docket, 39 The Environmental Forum 27 (2022).

Can Environmental Law Solve the "Forever Chemical" Problem?, 57 Wake Forest Law Review 101 (2022) (with Mark Nevitt). Abstract

The EPA as a Catalyst for the Development of Global Environmental Law, 70 Case Western Reserve Law Review 1151 (2020). Abstract

Transnational Environmental Accountability, Natural Resources & Environment, Fall 2020, at 8 (with Jingjing Zhang).

Environmental Law in the Supreme Court as the Kennedy Court Becomes the Roberts Court, Practical Real Estate Lawyer, March 2019, at 19.

Polar Opposites: Assessing the State of Environmental Law in the World's Polar Regions, 59 Boston College Law Review 1655 (2018) (with Mark P. Nevitt). Abstract

Could Official Climate Denial Revive the Common Law as a Regulatory Backstop?, 96 Washington University Law Review 441 (2018) (with Mark Nevitt). Abstract

Country Report: United States. Trump Administration Launches an Aggressive Rollback of Environmental Regulation and Pursues "Energy Dominance" for U.S., 9 IUCN Academy of Environmental Law eJournal 214 (2018).

Global Trends in Protection of Migratory Birds, 33 Natural Resources & Environment 43 (2018) (with Garrett Kral).

The "Greening" of the Global Judiciary, 32 Journal of Land Use and Environmental Law 333 (2017). Abstract

Environmental Law in the Trump Administration, 4 Emory Corporate Governance and Accountability Review 225 (2017). Abstract

The Judge Who Climbed Mountains, 69 Stanford Law Review 629 (2017). Abstract

Comparative Environmental Federalism: Subsidiarity and Central Regulation in the United States and China, 6 Transnational Environmental Law 531 (2017) (with Zhao Huiyu).

The Future of Environmental Enforcement, 47 Environmental Law Reporter 10206 (2017).

Environmental Law in the United States, 26 Yearbook of International Environmental Law 160 (2017).

Despite Attacks on Judicial Deference, Reports of Auer's Demise Are Premature, Trends, March/April 2017, at 4.

Country Report: United States: Election of President Trump Shocks Environmentalists and Threatens Obama Administration’s Environmental Legacy, 8 IUCN Academy of Environmental Law E-Journal 114 (2017).

USA Report: Congressional Opposition Fails to Halt Key Obama Administration Environmental Initiatives; Court Battles Loom as 2016 Presidential Election Approaches, 7 IUCN Academy of International Law E-Journal 275 (2016).

USA Report: EPA Continues Significant Regulatory Initiatives as Opponents of Environmental Regulation Prepare to Take Control of Both Houses of Congress, 6 IUCN Academy of Environmental Law E-Journal 434 (2015).

2014 Supreme Court Review and Preview, 45 Environmental Law Reporter 10005 (2015) (with John Cruden & E. Donald Elliott).

Time for a Restatement, 32 Environmental Forum 38 (January/February 2015) (with others)

Restating Environmental Law, 40 Columbia Journal of Environmental Law 1 (2015) (with others).

With Gridlock in Congress, Agencies and Courts Take Center Stage, 5 IUCN Academy of Environmental Law E-Journal 294 (2014).

Presidential Power to Address Climate Change in an Era of Legislative Gridlock, 32 Virginia Environmental Law Journal 134 (2014). Abstract

The Role of Civil Society in Environmental Governance in the United States and China 24 Duke Environmental Law & Policy Forum 142 (2014) (with Huiyu Zhao). Abstract

Book Review, 3 Transnational Environmental Law 407 (2014) (reviewing Rule of Law for Nature: New Dimensions and Ideas in Environmental Law, ed. Christina Voigt (2013)).

Looking Backward, Looking Forward: The Next 40 Years of Environmental Law, 43 Environmental Law Reporter 10492 (2013). Abstract

Can He Legally Do That? Does the President Have Directive Authority Over Agency Regulatory Decisions?, 37 Administrative Law & Regulatory Law News 4 (Spring 2012). Abstract

CERCLA in a Global Context, 41 Southwestern Law Review 727 (2012) (with Katherine H. Cooper and Matthew M. Gravens). Abstract

Setting the Bar for "Injury" in Environmental Cases: How Low Can it Go?, 42 Environmental Law Reporter 10785 (2012) (with John C. Cruden, Carla Burke, and John Guttmann). Abstract

Global Law and the Environment, 86 Washington Law Review 579 (2011). Abstract

China’s ‘Green Leap Forward’ Toward Global Environmental Leadership, 12 Vermont Journal of Environmental Law 633 (2011). Abstract

Who’s in Charge? Does the President Have Directive Authority over Agency Regulatory Decisions?, 79 Fordham Law Review 2487 (2011). Abstract

Liability for Environmental Harm and Emerging Global Environmental Law, 25 Maryland Journal of International Law 37 (2010). Abstract

The Globalization of Environmental Law, 26 Pace Environmental Law Review 451 (2009). Abstract

The Emergence of Global Environmental Law, 36 Ecology Law Quarterly 101 (2009) (with Tseming Yang). Abstract

Environmental Law in the 21st Century , in International Environmental Law and Comparative Environmental Law Review 204 (Wang Xi ed., 2008) (translated into Chinese by Professor Li Yanfang). Abstract

Environmental Law in the Twenty-First Century, 25 Virginia Environmental Law Journal 1 (2007).

Massachusetts v. EPA: Escaping the Common Law’s Growing Shadow, 2007 Supreme Court Review 111. Abstract

Who's Afraid of the Precautionary Principle?, 23 Pace Environmental Law Review 21 (2006). Abstract

Environmental Law in the Supreme Court: Highlights from the Blackmun Papers, 35 Environmental Law Reporter 10637 (2005). Abstract

Forum: Is Chinese Environmental Law up to the Task?, Environmental Forum, Sept. - Oct. 2005, at 44.

The Clean Water Act and the Demise of the Federal Common Law of Interstate Nuisance, 55 Alabama Law Review 717 (2004).

"Greening" the Constitution: Harmonizing Environmental and Constitutional Values, 32 Environmental Law 809 (2002).

Skeptical environmentalist or statistical spin-doctor?: Bjorn Lomborg and the Relationship between Environmental Law and Environmental Process, 53 Case Western Reserve Law Review 263 (2002).

Separation of Powers, the Presidency and the Environment, 21 Journal of Land, Resources and Environmental Law 25 (2001).

Escaping the Common Law’s Shadow: Standing in the light of Laidlaw, 12 Duke Environmental Law & Policy Forum 119 (2001) (with Joanna B. Goger).

Presidential Management of the Administrative State: The Not-so-Unitary Executive, 51 Duke Law Journal 963 (2001).

Environmental Legislation and the Problem of Collective Action, 9 Duke Environmental Law & Policy Forum, 9 (1998).

Regulatory Evolution and the Future of Environmental Policy, 1997 University of Chicago Legal Forum 159.

Responding to Environmental Risk: A Pluralistic Perspective, 14 Environmental Law Review 513 (1997).

Environmental Federalism: Historical Roots and Contemporary Models, 54 Maryland Law Review 1141 (1995).

Overcoming Interpretive Formalism: Legislative Reversals of Judicial Constructions of Sovereign Immunity Waivers in the Environmental Statutes, 43 Washington University Journal of Urban and Contemporary Law, 221 (1993).

The Ecology of Environmental Conflict: Risk, Uncertainty and the Transformation of Environmental Policy Disputes, 12 Studies in Law, Politics, and Society 209 (1992).

Checks without Balance: Executive Office Oversight of the Environmental Protection Agency, Law and Contemporary Problems, Autumn 1991, at 127.

Protecting Coastal and Estuarine Resources: Confronting the Gulf between the Promise and Product of Environmental Regulation, 47 Maryland Law Review 341 (1988).

The Processing of Felonies in the Superior Court of Alameda County, 5 Law & History Review 413 (1987) (with Lawrence M. Friedman).

The Bounds of Consent: Consent Decrees, Settlements and Federal Environmental Policymaking, 1987 University of Chicago Legal Forum 327.

The Role of Attorney Fee Shifting in Public Interest Litigation, Law & Contemporary Problems, Winter 1984, at 233.

A Tale of Two Courts, 10 Law & Society Review 267 (1976) (with Lawrence M. Friedman).

Who Sues for Divorce? From Fault Through Fiction to Freedom, 5 Journal of Legal Studies 61 (1976) (with Lawrence M. Friedman). Abstract