43. A Short Course in Greenhouse Gases
A Short Course in Greenhouse Gases The various “greenhouse gases” can be a source of confusion: carbon dioxide, methane, nitrous oxide, refrigerants (f-gases), sulfur hexafluoride, water vapor….How should we budget our concern about each of these? What is their relative importance in the strategy for addressing atmospheric warming? Back when some of us were young we learned all about the greenhouse effect as a GOOD thing: carbon dioxide (and a few other gases) in the atmosphere insulated the earth so all life could thrive. Now students have to learn about too-much-of-a-good-thing. Since the beginning of the industrial revolution the amount of these gases has steadily increased as a result of human activity. Primary among the greenhouse gases is carbon dioxide (CO2), but those above are also in the mix. For each of these gases we need to consider four factors that determine their long-term impact on global warming: the concentration; the global warming potential; the “lifetime” of the g