Question

Hydrofluorocarbons (HFCs) were used to phase out chlorofluorocarbons (CFCs), which were used as aerosol propellants, refrigerants, and coolants. Members from 197 nations meeting at the summit of the United Nations Environment Programme in Kigali, Rwanda reached a legally-binding accord to phase out HFCs in an amendment to the Montreal Protocol due to HFCs potential for A) global warming. B) increased cancer incidence. C) toxicity and biomagnification in aquatic ecosystems. D) contributing to habitat destruction of endangered animals.

Answer 1

Members from 197 nations meeting at the summit of the United Nations Environment Programme in Kigali, Rwanda reached a legally-binding accord to phase out HFCs in an amendment to the Montreal Protocol due to HFCs potential for global warming.

Step-by-step explanation:

The Phase-out Management Plan (HPMP) for Hydrochlorofluorocarbons (HCFCs)

Under the Montreal Protocol on Substances Depleting the Ozone Layer, in particular the Executive Committee (ExCom) 53/37 and ExCom 54/39, the Parties to this Protocol agreed to set 2013 as the time for developing countries to freeze consumption and development of HCFCs. For developing countries, the decline in consumption and production of HCFCs started in 2004 and 2010, respectively, with a decline of 100% set for 2020. Developing countries have agreed to start reducing their HCFC consumption and output by 2015, with a reduction of 100% set for 2030.

Hydrochlorofluorocarbons are a category of man-made compounds containing hydrogen, chlorine , fluorine and carbon, generally referred to as HCFCs. In nature, they are not found anywhere. After countries decided to phase out the use of CFCs in the 1980s, which were found to be damaging the ozone layer, HCFC production began to take off. HCFCs are used for refrigeration, aerosol propellants, foam processing and air conditioning, much like CFCs. However, unlike CFCs, most HCFCs in the lowest part of the atmosphere are broken down and pose a much smaller danger to the ozone layer. Nonetheless, considering their very low atmospheric concentrations, HCFCs are very potent greenhouse gases, measured in parts per trillion. Compared to CFCs with ODP 0.6-1.0, these HCFCs have lower ODPs (0.01-0.5) in terms of ozone depletion potential (ODP). Compared to CFCs with a GWP of 4,680-10,720, HCFCs have lower GWPs (76-2,270) in terms of global warming potential ( GWP).

Hydrofluorocarbons (HFCs), manufactured mostly in developing countries, have replaced CFCs and HCFCs. HFCs do not cause damage to the ozone layer because they do not contain chlorine, unlike CFCs and HCFCs. However, they are greenhouse gases, similar to that of CFCs and HCFCs, with a strong global warming potential ( GWP).

In the other three options ,there is no role of the members from 197 nations meeting at the summit of the United Nations Environment Programme in Kigali.

Hence, the correct option is A.