Realizing the Promise of Paris: Three Ways of Strengthening Non-State and Subnational Climate Action By Harro van Asselt, Sander Chan, Idil Boran, Thomas Hale, Lukas Hermwille and Charles Roger - 11 December 2020 Harro van Asselt, Sander Chan, Idil Boran, Thomas Hale, Lukas Hermwille and Charles Roger examine opportunities to strengthen climate action by non-state and subnational actors. Five years ago, governments from across the world came together in Paris to chart a new course for global climate policy. The Paris Agreement put in place a ‘ratchet mechanism’ through which countries submit national climate plans in the form of Nationally Determined Contributions (NDCs), which should be reviewed and strengthened periodically.