Although the agreement was welcomed by many, including French President François Hollande and UN Secretary-General Ban Ki-moon,[67] criticism also surfaced. For example, James Hansen, a former NASA scientist and climate change expert, expressed anger that most of the deal is made up of “promises” or goals, not firm commitments. [98] He called the Paris talks a fraud without “any action, only promises” and believes that only a cross-cutting tax on CO2 emissions, which is not part of the Paris Agreement, would reduce CO2 emissions fast enough to avoid the worst effects of global warming. [98] In 1992, at the Earth Summit in Rio, Brazil, President George H.W. Bush, along with 107 other heads of state, adopted a number of environmental agreements, including the UNFCCC framework, which is still in force today. The international treaty aims to prevent dangerous human interference in Earth`s climate systems in the long term. The Pact does not set greenhouse gas emission limits for each country and does not include enforcement mechanisms, but rather creates a framework for international negotiations on future agreements or protocols to set binding emission targets. Participating countries meet annually at a Conference of the Parties (COP) to assess their progress and continue discussions on how best to tackle climate change. On August 4, 2017, the Trump administration issued an official notice to the United Nations that the United States is important to remember, however, that the Paris Agreement is not static. .