197 countries signed the agreement which became legally binding about a year later, after countries responsible for 55% of global greenhouse gas emissions ratified it. 169 UNFCCC members have ratified the agreement to date.
Signatories agreed to keep the overall increase in global temperatures to below 2°C (beyond which, the impact of climate change is expected to be catastrophic), to try to limit the increase to 1.5°C, and to achieve zero net emissions in the second half of this century. In their Nationally Determined Contributions (NDCs), every signatory offered voluntary emission targets and set out their mitigation strategies to achieve these goals. They also agreed to a five-yearly review of their plans. Targets are expected to be tightened at each successive review.
While the NDCs are not legally binding, signatories are legally subject to expert review to ensure their progress towards achieving NDC goals.
Both developed and developing nations must report on their mitigation efforts every two years, and all signatories will be subject to both technical and peer review .
However most countries’ NDCs are not as robust as they need to be, and scientists have confirmed that even if all countries acted on everything they have pledged, global warming of 2.7 to 3.7°C would still occur.