montreal protocol to reduce production of chlorofluorocarbons was assigned in 26 august 1989.
montreal protocol to reduce production of chlorofluorocarbons was assigned in 26 august 1989.
montreal protocol to reduce production of chlorofluorocarbons was assigned in?
26 august 1989
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since the montreal protocol came into effect, the atmospheric concentrations of the most important chlorofluorocarbons and related chlorinated hydrocarbons have either leveled off or decreased. halon concentrations have continued to increase, as the halons presently stored in fire extinguishers are released, but their rate of increase has slowed and their abundances are expected to begin to decline by about 2020. also, the concentration of the hcfcs increased drastically at least partly because of many uses (e.g. used as solvents or refrigerating agents) cfcs were substituted with hcfcs. while there have been reports of attempts by individuals to circumvent the ban, e.g. by smuggling cfcs from undeveloped to developed nations, the overall level of compliance has been high. statistical analysis from 2010 show a clear positive signal from the montreal protocol to the stratospheric ozone. in consequence, the montreal protocol has often been called the most successful international environmental agreement to date. in a 2001 report, nasa found the ozone thinning over antarctica had remained the same thickness for the previous three years, however in 2003 the ozone hole grew to its second largest size. the most recent (2006) scientific evaluation of the effects of the montreal protocol states, "the montreal protocol is working: there is clear evidence of a decrease in the atmospheric burden of ozone-depleting substances and some early signs of stratospheric ozone recovery." however, a more recent study seems to point to a relative increase in cfcs due to an unknown source.
montreal protocol