<P> The amendment to the legally - binding Montreal Protocol will ensure that the rich and industrialised countries bring down their HFC production and consumption by at least 85 per cent compared to their annual average values in the period 2011 - 2013 . A group of developing countries including China, Brazil and South Africa are mandated to reduce their HFC use by 85 per cent of their average value in 2020 - 22 by the year 2045 . India and some other developing countries--Iran, Iraq, Pakistan, and some oil economies like Saudi Arabia and Kuwait--will cut down their HFCs by 85 per cent of their values in 2024 - 26 by the year 2047 . </P> <P> In 1973, the chemists Frank Sherwood Rowland and Mario Molina, who were then at the University of California, Irvine, began studying the impacts of CFCs in the Earth's atmosphere . They discovered that CFC molecules were stable enough to remain in the atmosphere until they got up into the middle of the stratosphere where they would finally (after an average of 50--100 years for two common CFCs) be broken down by ultraviolet radiation releasing a chlorine atom . Rowland and Molina then proposed that these chlorine atoms might be expected to cause the breakdown of large amounts of ozone (O) in the stratosphere . Their argument was based upon an analogy to contemporary work by Paul J. Crutzen and Harold Johnston, which had shown that nitric oxide (NO) could catalyze the destruction of ozone . (Several other scientists, including Ralph Cicerone, Richard Stolarski, Michael McElroy, and Steven Wofsy had independently proposed that chlorine could catalyze ozone loss, but none had realized that CFCs were a potentially large source of chlorine .) Crutzen, Molina and Rowland were awarded the 1995 Nobel Prize for Chemistry for their work on this problem . </P> <P> The environmental consequence of this discovery was that, since stratospheric ozone absorbs most of the ultraviolet - B (UV - B) radiation reaching the surface of the planet, depletion of the ozone layer by CFCs would lead to an increase in UV - B radiation at the surface, resulting in an increase in skin cancer and other impacts such as damage to crops and to marine phytoplankton . </P> <P> But the Rowland - Molina hypothesis was strongly disputed by representatives of the aerosol and halocarbon industries . The chair of the board of DuPont was quoted as saying that ozone depletion theory is "a science fiction tale...a load of rubbish...utter nonsense". Robert Abplanalp, the president of Precision Valve Corporation (and inventor of the first practical aerosol spray can valve), wrote to the Chancellor of UC Irvine to complain about Rowland's public statements (Roan, p. 56 .) </P>

Who is responsible for enforcing the montreal protocol