Environmental Protection Agency (EPA) MVAC Certification

How do HFCs contribute to global warming?

1. By causing ozone depletion

2. By enhancing greenhouse effects

3. By increasing atmospheric pressure

4. They do not contribute at all

The correct answer is: By enhancing greenhouse effects

Hydrofluorocarbons (HFCs) are synthetic compounds commonly used in refrigeration, air conditioning, and foam-blowing applications. Their contribution to global warming is primarily through their ability to enhance the greenhouse effect. HFCs have a high global warming potential (GWP), meaning that, per molecule, they can trap significantly more heat in the atmosphere compared to carbon dioxide. When released into the atmosphere, HFCs absorb infrared radiation and re-emit it, thereby preventing heat from escaping back into space. This mechanism aligns with the general principles of greenhouse gases, which include carbon dioxide and methane, in that they contribute to the warming of the planet by trapping heat. Other choices, such as the one suggesting that HFCs cause ozone depletion, are incorrect because HFCs were developed as alternatives to ozone-depleting substances like chlorofluorocarbons (CFCs). While they do not deplete the ozone layer, their impact on climate change remains significant due to their heat-trapping properties. Similarly, the option regarding atmospheric pressure is not applicable, and the notion that HFCs do not contribute to global warming contradicts well-established scientific findings regarding their role as potent greenhouse gases.