"Now, former EPA officials are calling for a redoubling of efforts to reduce or eliminate the gases, which remain in the atmosphere for up to 50,000 years."
"When Sally Rand, a former EPA official, used to meet with industry executives to discuss an obscure, but incredibly potent and long-lived group of greenhouse gases, she knew how to get their attention.
“I call[ed] them ‘the immortals,’” Rand said. “It sort of resonated. It’s like, look, every time it goes up, it’s gonna be there for all the rest of time.”
Rand was talking about a class of fluorinated gases that remain in the atmosphere for thousands of years. The man-made chemicals—sulfur hexafluoride (SF6), tetrafluoromethane (CF4) and hexafluoroethane (C2F6)—are released by the aluminum, magnesium, semiconductor and electric power industries.
The gases, which remain largely unregulated, stay in the atmosphere for anywhere from 3,200 years in the case of SF6, to 50,000 years for CF4. Once they are released, they are “essentially permanent additions to the atmosphere,” the EPA notes."