This document summarizes four important environmental law cases: 1) United States v. Washington affirmed Native American tribes' rights to fish salmon and other species according to historical agreements. 2) Earth Life Africa Johannesburg v. Minister of Environmental Affairs determined that environmental impact assessments in South Africa must consider effects of projects on climate change. 3) Gade v. National Solid Wastes Management Ass’n addressed whether federal health and safety laws preempted state laws requiring hazardous waste worker training. 4) Environmental Defence Society Inc v New Zealand King Salmon Co Ltd held that protecting exceptional natural landscapes was a primary environmental concern under New Zealand law.