Vernon is an Associate Professor at Auckland Law School. Prior to commencing a fulltime academic career, Vernon practiced environmental, planning and public law in Auckland, latterly as a partner at New Zealand national commercial law firm Chapman Tripp and as an environmental barrister sole.

His teaching and research activities focus on four (related) areas of interest: public law, climate change law, international environmental law and New Zealand environmental law. Over the course of his academic career, he has lectured in Public Law, Constitutional Law, Judicial Review, International Law, International Environmental Law, Resource Management Law and Climate Change Law. His current lecturing roles include LAW211 Public Law, LAWENVIR 433 Resource Management Law and LAWENVIR404 Climate Change Law. He also contributes to other environmental courses at the University of Auckland.

He has published widely in the areas of environmental and international environmental law. In 2019, his research on a 5-year New Zealand Law Foundation-supported project critiquing New Zealand and international law responses to fossil fuel subsidies culminated in publication of a monograph Fossil Fuel Subsidies: an International Law Response published by Edward Elgar. He is the author of Laws of New Zealand: Climate Change (LexisNexis NZ, Wellington, 2017); “International Environmental Law” in Alberto Costi (ed) Public International Law: A New Zealand Perspective (1st ed, LexisNexis NZ, Wellington, 2020); “The Influence of International Environmental Law on Domestic Law in Aotearoa New Zealand” in Peter Salmon and David Grinlinton (eds) Environmental Law in New Zealand (3rd ed, Thomson Reuters New Zealand, Wellington, 2026), and “Environmental Assessment” in Derek Nolan (ed) Environmental and Resource Management Law (7th ed, LexisNexis NZ, 2020).

Vernon is in the final stage of doctoral research at Melbourne University Law School examining the capacity of a fragmented international law system to respond to issues of climate change-related displacement and migration in Moana-Nui-a-Kiwa (Oceania).