Environmental problems are the troubles of politics, economics, and philosophy. They are often bitter troubles, revealing deep divisions in societies over how life should be lived. These divisions concern global environmental problems and also environmental issues that affect specific communities. ‘Troubles’ explains how environmental law is a necessary response to environmental problems providing legislation, case law, international agreements, and regulatory strategies to address the collective nature of environmental problems. It also ensures that collective action in relation to environmental problems is authoritative and consistent with the rule of law and other principles of legitimate action. Environmental law is built on existing legal frameworks, but often requires the development of new legal obligations and doctrine.