While the agreement has been welcomed by many, including French President Francois Hollande and UN Secretary-General Ban Ki-moon, 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.  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.  “accession” in the event that a country becomes a party to an international agreement already negotiated and signed by other countries. It has the same legal effect as ratification, acceptance and approval. Membership usually takes place after the agreement comes into force, but it can also take place in advance depending on the terms of the agreement. The agreement recognizes the role of non-partisan stakeholders in the fight against climate change, including cities, other sub-national authorities, civil society, the private sector and others. 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. China, for example, has committed to cleaning up its CO2 emissions by 2030 at the latest and reducing CO2 emissions per unit of gross domestic product (GDP) by 60-65% by 2030 from 2005 levels. India has set a target of reducing emissions intensity by 33-35% from 2005 levels by 2030 and producing 40% of its electricity from non-fossil fuels. Although the United States and Turkey are not parties to the agreement, as they have not indicated their intention to withdraw from the 1992 UNFCCC, they will continue to be required, as an “Annex 1” country under the UNFCCC, to end national communications and establish an annual inventory of greenhouse gases.  These rules of transparency and accountability are similar to those set out in other international agreements. Although the system does not include financial sanctions, the requirements are intended to easily monitor the progress of individual nations and promote a sense of overall group pressure, discouraging any towing of feet among countries that might consider it. To contribute to the goals of the agreement, countries presented comprehensive national climate change plans (national fixed contributions, NDC). These are not yet sufficient to meet the agreed temperature targets, but the agreement points to the way forward for further measures. On August 4, 2017, the Trump administration officially announced to the United Nations that the United States intends to withdraw from the Paris Agreement as soon as it is legally entitled to it.  The formal declaration of resignation could not be submitted until after the agreement for the United States came into force on November 4, 2019 for a three-year date.
  On November 4, 2019, the U.S. government filed the withdrawal notice with the Secretary-General of the United Nations, custodian of the agreement, and formally withdrew from the Paris Agreement a year later, when the withdrawal came into effect.  After the November 2020 elections, President-elect Joe Biden promised to reinstate the United States in the Paris Agreement for his first day in office and renew the U.S. commitment to climate change mitigation.   Although the slowdown and adjustment require more climate funding, adjustment has generally received less support and less private sector action.  A 2014 OECD report showed that in 2014, only 16% of the world`s financial resources were devoted to