The Top Ten Greenhouse Gases

PopSci.com's guide to the vapors that are making Earth more toasty

Despite all the talk about carbon capture, carbon footprints and carbon trading, carbon dioxide only causes nine to 26 percent of the greenhouse effect. That means that the majority of warming results from gases with a much lower media profile than the paparazzi-trailed starlet of global warming, CO2. In honor of last weeks' report in the Journal of Geophysical Research, which identified a brand new greenhouse gas, PopSci.com counts down the gases that bring us bikini weather in Antarctica and beachfront property in Montana.

10. Sulfuryl Fluoride

The new kid on the block, MIT scientists identified this chemical as a greenhouse gas on March 11th, 2009. Used as a fumigant, Dow Chemicals produces sulfuryl fluoride to kill termites. The chemical, which is highly inert, has a lifetime of up to 40 years, and traps 4,800 times more heat per molecule than CO2. The chemical only exists in 1.5 parts per trillion in the atmosphere, but according to the recent Journal of Geophysical Research, that number is going up by 5 percent a year.Termite tent, courtesy of the Monterey Public Library via Flickr.com

9. Trichlorofluoromethane

This refrigerant has the dubious honor of contributing to warming on two fronts. Not only goes does trichlorofluoromethane retain heat 4,600 times better than carbon dioxide, but it also depletes the ozone layer faster than any other refrigerant. The high ozone-depletion rate results from trichlorofluoromethane's tendency to shed chlorine molecules when struck with ultraviolet light. Chlorine, of course, is also a deadly toxin.Refigerator in parking lot, courtesy of Rich Anderson via Flickr.com

8. Sulfur Hexafluoride

Primarily used in the electronics industry as an insulator, this inert gas moonlights as a tracer for experiments around the wind dispersal of toxic gases during terrorist attacks. The Intergovernmental Panel of Climate Change (IPCC) deemed sulfur hexafluoride the world's most powerful greenhouse gas, with the chemical weighing in at a stout 22,200 times more heat trapping than CO2.Resistors, courtesy of Steve Lodefink via Flickr.com

7. Hexafluoroethane

A chemical used in the creation of semiconductors, hexafluoroethane is the Methuselah of greenhouse gases. While some chemicals linger in the atmosphere for mere decades, hexafluoroethane sticks around for 10,000 years. That longevity, combined with heat retention 9,200 times greater than carbon dioxide, makes hexafluoroethane a chemical the IPCC keeps a close eye on.Computer chips, courtesy of jpockele via Flickr.com

6. Trifluoromethane

Trifluoromethane, also called fluoroform, serves two purposes, finding use in the etching of silicon computer chips and as a fire suppressant. By far the most abundant of the hydrofluorocarbons, trifluoromethane has an atmospheric lifetime of 260 years and traps 11,700 times as much heat as carbon dioxide.Fire extinguisher in action, courtesy of rockstarassi via Flickr.com

5. Ozone

Usually when ozone comes up in the climate debate, the talk centers on a general lack of it. In fact, ozone is also a potent greenhouse gas. But because ozone isn't equally distributed around the globe, we have simultaneously too much of it (man-made ozone in the lowest part of the atmosphere traps heat and warms the planet), and too little of it (fluorocarbons deplete ozone in the upper atmosphere responsible for shielding the ice caps from solar radiation).Sunset on an ozone alert day, courtesy of Haunted by Leonard Cohen via Flickr.com

4. Nitrous Oxide

By far the most fast and furious of the greenhouse gases, nitrous finds uses in rocket fuel, making cars more awesome, and as a recreational drug. However, those indulging in huffing and street racing should be aware that laughing gas ranks as the fourth leading caus of the greenhouse effect.Car with nitrous booster, courtesy of Chris Breeze via Flickr.com

3. Methane

The main component of natural gas and cow farts, methane comes in as the number three worst offending greenhouse gas. The IPCC freely admits that it does not fully understand the methane cycle, and identifies methane release as coming from natural sources like swamps and termites, and from man-made sources like landfills and cow farms.Cow in Dedham, Essex, England, courtesy of law Kevin via Flickr.com

2. Carbon Dioxide

Despite getting all the press, carbon dioxide only ranks as the second largest contributor to global warming. For those who managed to stay awake while listening to Al Gore's relentless monotone, you can skip ahead to number one. But for all of those who drifted off, let's reiterate that CO2 is a by-product of the combustion of fossil fuels as well as cellular respiration, and carbon dioxide generated by human industry contributes to the warming of the planet.: Drax coal-fired power plant, North Yorkshire England, courtesy of thewritingzone via Flickr.com

1. Water Vapor

Water? Water?! Water! Yes, according to the IPCC, steam accounts for 36-70 percent of the greenhouse effect. Fog, haze and clouds are all water vapor, and steam is the other main byproduct of the combustion of fossil fuels. Worse still, warming causes a positive feedback loop as higher temperatures result in more water vapor, which results in higher temperatures, and so on and so on. Now the next time someone asks you about your carbon footprint, you can ask them about their steam footprint, and see if that patchouli-scented hippie knows the main cause behind the greenhouse effect.Clouds, courtesy of Shek Graham via Flickr.com