While the agreement has been welcomed by many, including French President Francois Hollande and UN Secretary-General Ban Ki-moon,[67] criticism has also emerged. James Hansen, a former NASA scientist and climate change expert, expressed anger that most of the agreement is made up of “promises” or goals, not firm commitments. [98] He called the Paris talks a fraud with “nothing, only promises” and believed that only a generalized tax on CO2 emissions, which is not part of the Paris agreement, would force CO2 emissions down fast enough to avoid the worst effects of global warming. [98] Although mitigation and adjustment require increased climate funding, adjustment has generally received less support and has mobilized less private sector action. [46] A 2014 OECD report showed that in 2014, only 16% of the world`s financial resources were devoted to adaptation to climate change. [50] The Paris Agreement called for a balance between climate finance between adaptation and mitigation, highlighting in particular the need to strengthen support for adaptation from the parties most affected by climate change, including least developed countries and small island developing states. The agreement also reminds the parties of the importance of public subsidies, as adjustment measures receive less public sector investment. [46] John Kerry, as Secretary of State, announced that the United States would double its grant-based adjustment funding by 2020. [33] This letter examines how the Paris Agreement is spurring progress on the three pillars of the fight against climate change – reducing greenhouse gas pollution, mobilizing climate finance and adapting to the effects of climate policy – and how it resolves several persistent controversies within the UNFCCC.

President Obama was able to formally enshrine the United States in the agreement through executive measures because he did not impose new legal obligations on the country. The United States already has a number of instruments on the books, under laws already passed by Congress to reduce carbon pollution. The country officially joined the agreement in September 2016, after submitting its request for participation.