Your Guide to Greenhouse Gases Carbon dioxide you know, but what about perfluorocarbons? By Will McCahill, Newser Staff Posted Dec 13, 2009 3:35 PM CST 22 comments Comments Smoke pour from a Beijing plant. (AP Photo) (Newser) – With things set to really heat up next week at the Copenhagen climate summit, the Guardian runs down greenhouse gases you oughta know: Carbon dioxide (CO2): Industrialization and deforestation have produced high levels of this gas, which helps trap heat inside Earth’s atmosphere. Methane (CH4): Thirty times more dangerous than CO2, it’s mainly a byproduct of agriculture—think burping cows. But much less methane than carbon dioxide is produced. Nitrous oxide (N2O): Commonly called laughing gas, it’s the third-worst gas in terms of turning up the heat. Hydrofluorocarbons (HFCs): Used in cooling systems after chlorofluorocarbons were phased out, HFCs now cause 1% of warming and are being regulated, too. Perfluorocarbons (PFCs): Released in various manufacturing processes, these gases don’t ever really break down in the atmosphere. For the rest of the list, click the link at right.