The Paris Agreement is the world's first comprehensive climate agreement that requires emissions reductions from all countries. It aims to limit global warming to well below 2°C by having countries set and strengthen their own emissions reduction targets through nationally determined contributions (NDCs) every 5 years. While it does not enforce compliance, 185 countries have signed on and it entered into force in 2016 after ratification by over 55 countries representing over 55% of global emissions. Critics argue the initial NDCs are insufficient and countries are not implementing the policies envisioned, but the agreement creates a framework for increasing climate action over time.