Since then, the world has made rapid progress: the virtual elimination of ozone-depleting substances and the trend towards recovery of the ozone layer are probably one of the most successful international environmental cooperations to date. In this section, we present data on ozone depletion, signs of recovery, emissions of ozone-depleting substances, international agreements and cooperation, and the consequences of ozone depletion. If the development of the SDO had continued until 2020, the WMO project, according to which total greenhouse gas emissions from halogen gases would have been about 20 billion tonnes of CO2 equivalent (compared to 36 billion tonnes of CO2 in 2017) – this would have been an increase of more than 50% over global greenhouse gas emissions. But the Rowland-Molina hypothesis has been hotly contested by representatives of the aerosol and halocarbon industry. The chairman of DuPont`s board of directors was quoted as saying that the ozone depletion theory was “a science fiction story… A shipment of rubbish… total nonsense.” Robert Abplanalp, President of Precision Valve Corporation (inventor of the first practical valve of the aerosol bomb), wrote to the clerk of UC Irvine complaining about Rowland`s public statements (Roan, 56). The treaties are also remarkable in the unique utility of global action, with only 14 years signed between a fundamental scientific discovery (1973) and the international agreement (1985 and 1987). The ecological consequence of this discovery was that, since stratospheric ozone absorbs most of the ultraviolet B (UV-B) radiation reaching the planet`s surface, the depletion of the ozone layer by CFCs would result in an increase in UV-B radiation on the surface, resulting in an increase in skin cancers and other effects such as damage to crops and marine phytoplankton.
Montzka et al. (2018) indicate that this should delay the recovery of ozone. However, this could be minimized (to a few years) if emissions are now rapidly reduced (again close to zero, as reported to the ozone secretariat). This change creates market security and opens up international markets for new technologies, which are better for the environment without compromising performance. It calls on all countries to gradually reduce their production and consumption of CFCs over the coming decades using the flexible, innovative and effective approaches adopted by the Montreal Protocol over the past three decades. Global stakeholders supported the adoption of the Kigali amendment, including most of the large U.S. companies operating in related sectors. But the CFC industry has not abandoned it so easily. As far back as 1986, the Alliance for Responsible CFC Policy (an association representing the CFC industry founded by DuPont) argued that science was too uncertain to warrant action.