In 2020, the Paris Agreement is the pinnacle of international law on climate change. It orchestrates global climate action over the coming decades. Countries agreed to limit global warming to well below 2°C above preindustrial times, closer to 1.5°C. Humankind will only achieve this temperature goal if we domesticate our international climate commitments. Judges have proven to be instrumental in holding their governments accountable for their climate pledges. Report Four of this four-part series explores the nature of the Paris Agreement, its history, and the framework of international instruments and international legal principles that support global and domestic climate action.