Greta Stacy is a high school science teacher in Doha, Qatar. She has previously taught in Ecuador and the United States.
Teaching about CFCs is important because it allows students to consider the impacts of greenhouse gases beyond just carbon dioxide in the atmosphere. This Chemistry Lesson: The Ozone Layer allows students to investigate the ways in which CFCs impact the ozone layer, as well as see a positive example of international cooperation to protect the environment. For younger students, this collaborative game Becoming Greenhouses Gases helps students understand the role specific greenhouse gases (including CFCs) play in climate change. Creating a deeper understanding of greenhouse gases allows students to make connections between human action and climate change in a more realistic way, which in turn allows for more realistic discussions about solutions to the climate crisis.
Written By: MIT Environmental Solutions Initiative
The MIT Climate Change Engagement Program, a part of MIT Climate HQ, provides the public with nonpartisan, easy-to-understand, and scientifically-grounded information on climate change and its solutions.
Carbon dioxide (CO2) is the most well-known and significant greenhouse gas causing climate change. But there are others, including methane, nitrous oxide—and chlorofluorocarbons (CFCs). CFCs were developed in the late 1920s to replace toxic compounds used in refrigeration and air conditioning; they have also been used in aerosols and as solvents. And while they’ve never been nearly as abundant as CO2, these compounds are much more potent at trapping heat in the atmosphere.
Greenhouse gases warm the earth by absorbing infrared radiation, light invisible to the human eye but important to our planet because it’s how the Earth gives off heat. By intercepting this light as it makes its way out to space, these gases keep more heat energy in our atmosphere. Different greenhouse gases absorb this radiation at different wavelengths of the infrared spectrum.
Chemical bonds in CFC molecules, particularly the carbon-chlorine and carbon-fluorine bonds, are very efficient at absorbing this infrared radiation. CFCs also absorb light in a part of the infrared spectrum that more abundant greenhouse gases like CO2 and water vapor do not. By capturing that heat that would otherwise escape into space, even a small amount of CFC molecules can have a significant impact on warming. And CFCs can also last a long time in the atmosphere because they don’t react readily with other compounds, only sunlight.
