GEOG 2300 1st Edition Lecture 14Outline of Last Lecture I. PaleoclimateII. Paleoclimate ToolsIII. Greenhouse EffectOutline of Current Lecture I. Global Energy BalanceII. Global Climate ChangeCurrent LectureI. Global Energy BalanceA. On a winter day like today, which will cause the coldest conditions? Clear skies – clouds trap heatB. Radiative Feedback: any change in the environment leading to additional and enhanced changes in that system is the result of a positive feedback mechanism, alternatively if a change in the environment leads to a compensating process that mitigates the change, it is a negative feedback mechanism II. Global Climate ChangeA. Carbon dioxide is the major greenhouse gas because there is so much of it and it stays in the atmosphere for a long timeB. Methane is a more powerful greenhouse gas but there is less of itC. Human activity and industrialization has led to an exponential rise in greenhouse gasesD. CFC’s caused the holes in the ozone layer; CFC’s then phased outE. Water vapor: 36-70% of the greenhouse effect on Earth (not including clouds), part of the hydrologic cycle, self-regulatingF. Carbon dioxide: 9-26%, Methane: 4-9%, Ozone: 3-7%G. Numbers don’t add up to 100, it’s not an exact thingH. Atmospheric lifetime: how long it takes to restore the system to equilibrium following a small increase in the concentration of the gas in the atmosphere, water has a short lifetime, while carbon dioxide has a long lifetime (200-450 years), methane has a lifetime of 12 years (+ or – 3)I. Global Warming Potential: GWP, relative measure of how much heat a greenhouse gas traps in the atmosphere, compares the amount of heat These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.trapped by a certain mass of the gas in question to the amount of heat trapped by a similar mass of another gas, (20) carbon dioxide=1, methane=62, nitrous oxide=275, CFC-12=10200J. After 1860 the amount of greenhouse gases skyrockets due to fossil fuel burning, deforestation, and agricultureK. Which is not a method for gathering evidence of past climates? Modeling projected climate changesL. Carbon dioxide levels fluctuate seasonally because of blooming of the plants, which take carbon dioxide out of the atmosphereM. Hydrofluorocarbons: HFC’s used as propellants, potent greenhouse gas, popular in refrigerators and car air condithionersN. Aerosol effect: caused by sulfur
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