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Zorluk: OrtaClimate Change, Global Warming and Ozone Layer Depletion

Hydrofluorocarbons (HFCs) were introduced as non-ozone-depleting alternatives to Chlorofluorocarbons (CFCs) and Hydrochlorofluorocarbons (HCFCs). Which of the following statements correctly explains why HFCs are being phased down globally under the 2016 Kigali Amendment to the Montreal Protocol?

  1. They have high Global Warming Potentials (GWPs), acting as powerful greenhouse gases that significantly contribute to global warming.Cevap
  2. B
    They breakdown rapidly in the stratosphere to release active chlorine radicals that catalyze catalytic ozone destruction cycles.
  3. C
    They react directly with tropospheric nitrogen oxides (NOxNO_x) to form toxic ground-level smog and secondary organic aerosols.
  4. D
    They freeze at ambient stratospheric temperatures to create Polar Stratospheric Clouds (PSCs) that accelerate ozone hole formation.

Cevap

Hydrofluorocarbons are being phased down under the Kigali Amendment because they possess high Global Warming Potentials (GWPs) and act as potent greenhouse gases.
The statement identifying high Global Warming Potentials (GWPs) is correct. While Hydrofluorocarbons do not damage the stratospheric ozone layer (ODP = 0), they are extremely potent greenhouse gases capable of trapping significant heat in the atmosphere. The 2016 Kigali Amendment to the Montreal Protocol was specifically designed to phase down HFCs to prevent additional global temperature rise.

Adım Adım Çözüm

1
Identify the chemical nature and ozone depletion potential of HFCs
HFCs contain hydrogen, fluorine, and carbon, but no chlorine or bromine atoms. As a result, their Ozone Depletion Potential (ODP) is virtually zero.
Understanding why HFCs replaced CFCs helps differentiate their impact on ozone depletion versus global warming.
2
Analyze the environmental threat posed by HFCs
Despite having zero ODP, HFCs are potent greenhouse gases with Global Warming Potentials (GWPs) ranging from hundreds to over 10,000 times that of carbon dioxide (CO2CO_2).
High GWP compounds trap thermal infrared radiation efficiently, accelerating planetary warming.
3
Connect the environmental impact to the Kigali Amendment objective
The 2016 Kigali Amendment legally amended the Montreal Protocol to mandate a global phase-down of HFC production and consumption to avoid up to 0.5 °C of warming by the end of the century.
The amendment expanded the scope of the Montreal Protocol from strictly protecting stratospheric ozone to mitigating climate change caused by HFC substitutes.

Anahtar Kavram

Kigali Amendment and Global Warming Potential of HFCs
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Climate Change, Global Warming and Ozone Layer Depletion