President Obama was able to formally integrate the United States into the international agreement through executive measures, as he did not impose new legal obligations on the country. The United States already has a number of instruments in its books, in line with laws already passed by Congress, to reduce carbon pollution. The country formally acceded to the agreement in September 2016, after presenting its proposal for participation. The Paris Agreement can only enter into force if at least 55 countries representing at least 55% of global emissions have formally acceded to it. This was done on October 5, 2016 and the agreement entered into force 30 days later on November 4, 2016. The agreement formally entered into force on 4 November 2016, a few days before COP22, and has been ratified by 169 countries (including the European Union 28), which account for 87.75% of emissions. At the 2011 UN Climate Change Conference, the Durban Platform (and the Ad Hoc Working Group on the Durban Platform for Enhanced Action) was created with the aim of negotiating a legal instrument to tackle climate change from 2020. The resulting agreement is expected to be adopted in 2015.  It will also allow the Parties to progressively strengthen their contribution to the fight against climate change in order to achieve the long-term objectives of the Agreement. It is an agreement with an “agenda for action” to implement accelerators to ensure more ambitious progress, going beyond binding commitments. The Paris Agreement is the world`s first comprehensive climate agreement.
 As host and president of COP21, France is committed to supporting a multilateral negotiation process and listening to all stakeholders to reach an agreement: the long-term temperature objective of the Paris Agreement is to keep the increase in global average temperature well below 2°C (3.6°F) above pre-industrial levels; and continue efforts to limit the increase to 1.5°C (2.7°F), which will significantly reduce the risks and effects of climate change. This should be done by reducing emissions as quickly as possible in order to “achieve, in the second half of the twenty-first century, a balance between anthropogenic emissions from sources and greenhouse gas reductions from sinks”. It also aims to increase the parties` ability to adapt to the negative effects of climate change and to “reconcile financial flows with a path towards low greenhouse gas emissions and climate-resilient development”. NRDC is working to make the Global Climate Action Summit a success by inspiring more ambitious commitments for the historic 2015 agreement and strengthened initiatives to reduce pollution. The agreement recognises the role of non-stakeholders in the fight against climate change, including cities, other sub-national authorities, civil society, the private sector and others. The Paris Agreement has a “bottom-up” structure, unlike most international environmental treaties, which are “top-down” and are characterized by internationally defined norms and goals that states must implement.  Unlike its predecessor, the Kyoto Protocol, which sets commitment targets that have the force of res judicata, the Paris Agreement, focused on consensus-building, allows for voluntary and national targets.  Specific climate objectives are therefore more politically encouraged than legally linked. . . .