The Paris climate agreement will enter into force on 4 November 2016. Under the agreement, all governments that have ratified the agreement, which includes the United States, China, India and the EU, are now required to keep global warming above pre-industrial levels. This is what scientists see as the limit of security, beyond which climate change can probably become catastrophic and irreversible. The entry into force of the Paris Agreement was extremely rapid, especially for an agreement that required a large number of ratifications and two specific thresholds. In the run-up to COP 21, many observers expected the Paris Agreement to enter into force after 2020, in line with the ADP`s mandate. However, Article 21 of the Paris Agreement does not contain a date when the agreement enters into force. Therefore, the speed with which countries are able to complete their national authorisation procedures depends on how quickly they are able to conclude their national authorisation procedures. It is likely that the Paris agreement will enter into force well before 2020. The entry into force of the Paris Agreement has a number of important effects. The Paris Agreement has an “upward” structure unlike most international environmental treaties, which are “top down”, characterized by internationally defined standards and objectives that states must implement.  Unlike its predecessor, the Kyoto Protocol, which sets legal commitment targets, the Paris Agreement, which focuses on consensual training, allows for voluntary and national objectives.  Specific climate targets are therefore politically promoted and not legally binding.
Only the processes governing reporting and revision of these objectives are imposed by international law. This structure is particularly noteworthy for the United States – in the absence of legal mitigation or funding objectives, the agreement is seen as an “executive agreement, not a treaty.” Since the 1992 UNFCCC treaty was approved by the Senate, this new agreement does not require further legislation from Congress for it to enter into force.  In the end, all parties recognized the need to “prevent, minimize and address losses and damages,” but in particular any mention of compensation or liability is excluded.  The Convention also takes up the Warsaw International Loss and Damage Mechanism, an institution that will attempt to answer questions about how to classify, address and co-responsible losses.  Countries cannot withdraw the agreement from the agreement for three years after it enters into force. If a country decides to withdraw at the end of this period, it will have to wait another year before it can formally withdraw. InDCs become CNDs – nationally determined contributions – as soon as a country formally adheres to the agreement. There are no specific requirements as to how or how many countries should reduce emissions, but there were political expectations about the nature and rigour of the targets set by different countries. As a result, the scale and ambition of national plans vary widely, largely reflecting each country`s capacity, level of development and contribution to emissions over time.