Gross domestic product (GDP) is the most widespread measure of national economic performance. Maintaining economic growth in the direction of GDP is a widely accepted indicator of economic success. Although different countries may calculate GDP in a slightly different way and discuss activities included or excluded from the measure, GDP remains an essential benchmark for economic performance. The volume of greenhouse gas emissions per unit of GDP should therefore be considered a key indicator (NGRS, 1995) when airlines release more than the capped amount they need to purchase CO2-reducing credits. CORSIA is divided into two phases: the first phase from 2021 to 2027 is voluntary, while phase two, which will begin in 2028, is mandatory and will take place in 2035. At the time of publication, 65 states, representing more than 86.5% of international aviation activity, stated that they were willing to participate voluntarily in Phase 1 of CORSIA. If full compliance is achieved, the Environmental Defence Fund estimates that greenhouse gas emissions would be reduced by 2.5 billion tonnes, or an annual reduction of 35 million cars for the longevity of the agreement. Human activities increase atmospheric concentrations of greenhouse gases – which tend to warm the atmosphere – and still in some aerosol regions – that tend to cool the atmosphere. These combined changes in greenhouse gases and aerosols are expected to result in regional and global changes in climate and climate parameters such as temperature, precipitation, soil moisture and sea level. Based on the range of climate sensitivities reported by the IPCC Working Group I for increasing greenhouse gas concentrations and plausible emission zones (IPCC 1992), experienced climate models, taking into account greenhouse gases and aerosols, an increase in the average global surface temperature of about 1-3.5oC by 2100 and a rise in sea level of about 15 to 95 cm. The reliability of regional forecasts remains low and the extent to which climate variability may change is uncertain. However, potentially serious changes have been observed, including an increase in extreme high temperature events, floods and droughts in some areas, with the following consequences of fires, outbreaks of pests and the composition, structure and functioning of the ecosystem, including primary productivity (IPCC, 1995). The United States signed the protocol on November 12, 1998, under President Clinton.
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.  Although the Clinton administration signed the treaty, it was never submitted to the Senate for ratification.