When it comes to climate change, carbon dioxide may get all the attention, but it's not the only greenhouse gas. In fact, it's not even the strongest, on a molecule-by-molecule basis—not by a long shot. The “greenhouse warming potential” of a gas is a measure of how good the gas is at trapping heat, crossed with how long it tends to hang around in the atmosphere. So while carbon dioxide gas has a greenhouse warming potential of 1, methane, or natural gas, has a potential of 34. In a new study, a team of researchers have reported the discovery of a gas that has one of the highest greenhouse warming potentials ever seen: 7,100.
The gas, perfluorotributylamine, or PFTBA, says the Guardian, has been “in use by the electrical industry since the mid-20th century.” PFTBA is produced in or imported into the U.S. at scales higher than a million pounds per year. No one knows how much of it escapes to the atmosphere. Because it's a complex chemical with no natural analogue, say the scientists in their study, there are no biological sinks out there in the world waiting to pull it out of the atmosphere, like trees do to carbon dioxide. They think that PFTBA probably hangs out in the air for at least 500 years, before it its broken down by chemical reactions in the upper atmosphere
PFTBA, say the scientists, is the most efficient greenhouse gas they've ever seen, on a molecule-by-molecule basis. But, because other greenhouse gases stay in the atmosphere longer, some, like sulfur hexafluoride, have higher greenhouse warming potentials.
The scientists say that if the concentration of perfluorotributylamine measured in Toronto, where they did their research, was the same all over the world (a pretty big assumption), then at its current levels the gas would be responsible for trapping 0.00015 watts of energy for every square meter of the planet. By comparison, carbon dioxide is responsible for 1.56 watts per square meter. But even if PFTBA isn't evenly distributed all over the planet, it could still be an important factor contributing to local warming.
What this really means is that carbon dioxide, produced by burning fossil fuels and other activities, is definitely still the dominant driver of global warming. But, we need to take care to not get tunnel vision because, if we're not careful, there are these other, newer gases that could cause just as much trouble at much lower concentrations.
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