The range of temperature projections partly reflects different projections of future greenhouse gas emissions. [17]22-24 Divergent projections contain different assumptions for future social and economic development (economic growth, population level, energy policy), which affects projections of future greenhouse gas emissions. [17]22-24 The sector also reflects uncertainty in the climate system`s response to past and future ThG emissions (measured in terms of climate sensitivity). [17]:22-24 The United States signed the protocol on November 12, 1998,[98] during the Clinton presidency. However, in order to become binding on the United States, the treaty had to be ratified by the Senate, which had already adopted the non-binding Byrd Hagel resolution in 1997, in which it expressed the rejection of an international agreement that did not require developing countries to reduce their emissions and “would seriously harm the U.S. economy.” The resolution was adopted by 95-0. [99] Although the Clinton administration signed the treaty,[100] it was never submitted to the Senate for ratification. The protocol is based on the principle of common but differentiated responsibilities: it recognises that different countries have different capacities to combat climate change because of economic development and, therefore, forces industrialized countries to reduce current emissions and thus forces them to reduce current emissions from industrialized countries, which are historically responsible for the current level of greenhouse gases in the atmosphere. In 2016, when the Paris climate agreement came into force, the United States was one of the main architects of the agreement, and President Obama hailed it as “a tribute to American leaders.” Then presidential candidate Donald Trump criticized the deal as a bad deal for the American people and promised to withdraw the United States if elected.

After a series of lectures entangled in differences of opinion, the delegates of COP21, held in Paris in 2015, signed a comprehensive but non-binding agreement to limit the rise in global average temperature to a maximum of 2 degrees Celsius (3.6 degrees Fahrenheit) above pre-industrial levels, while maintaining this increase to 1.5 degrees Celsius (2.7 degrees Fahrenheit) above pre-industrial levels. The pioneering agreement, signed by the 196 signatories of the UNFCCC, effectively replaced the Kyoto Protocol. In addition, a review of progress every five years and the development of a $100 billion fund by 2020 – which was to be replenished annually – was imposed to help developing countries implement technologies that are not generated by greenhouse gases. Kyoto Protocol, in the middle of the Kyoto Protocol to the United Nations Framework Convention on Climate Change, an international treaty, named after the Japanese city that adopted it in December 1997, which aimed to reduce the emissions of gases that contribute to global warming. The protocol, in force since 2005, called for emissions of six greenhouse gases in 41 countries plus the European Union during the 2008/2012 “commitment period” to be 5.2% below 1990 levels. It has been widely touted as the most important environmental treaty ever negotiated, although some critics have questioned its effectiveness.