Final answer:
Most HFC refrigerants have a global warming potential thousands of times greater than CO₂ due to their long atmospheric residence times, which has led to international agreements to control their emissions.
Step-by-step explanation:
Most HFC refrigerants have a global warming potential (GWP) thousands of times greater compared to carbon dioxide (CO₂). Greenhouse gases such as methane (CH₄) and nitrous oxide (N₂O) have higher GWPs than CO₂, with CH₄ being about 28 times more effective and N₂O being 298 times more effective at absorbing infrared radiation. The synthetic fluorinated gases, particularly HFCs, have GWPs that are much higher, largely due to their very long residence time in the atmosphere. The alarming potential of these gases to contribute to global warming has led to international environmental agreements such as the Montreal Protocol to phase out their predecessors, the CFCs, and to control HFC emissions.