The Greenhouse Effect and Climate Change - Other Greenhouse Gases

Other primary greenhouse gases are what the DOE calls "engineered gases." These are gases specially designed for modern industrial and commercial purposes. They include hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), and sulfur hexafluoride (SF6).

HFCs are chemicals that contain hydrogen, fluorine, and carbon. They are popular substitutes in industrial applications for chlorofluorocarbons (CFCs). CFCs are commonly used in cooling equipment, fire extinguishers, as propellants, and for other uses. They are blamed for depletion of the ozone layer in the stratosphere, which shields the Earth from deadly ultraviolet radiation.

FIGURE 2.8
World carbon dioxide emissions from the consumption and flaring of fossil fuels, 2001

PFCs are a class of chemicals containing fluorine and carbon. They also are increasingly used by industry as substitutes for ozone-depleting CFCs. SF6 is a colorless, odorless gas commonly used as an insulating medium in electrical equipment and as an etchant (an etching agent) in the semiconductor industry.

Although emissions of these chemicals are very small in comparison to other greenhouse gases, they are of particular concern because of their long life in the atmosphere. PFCs and SF6 have atmospheric lifetimes of thousands of years and are actually far more potent greenhouse gases than CO₂ per unit of molecular weight.