ISS 310 Lecture Notes - Lecture 8: Externality, Extinction, Sea Level Rise
20 Sep 2016
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Document Summary
Carbon cycle: movement of carbon between crust, oceans, atmosphere, plants, soil, animals. Most of earth"s carbon is a in crust. Co2 is most common gaseous form of carbon. Photosynthesis: conversion of carbon dioxide into organic compounds (sugar and oxygen) 2 billion years ago: atmosphere had more co2, less o2. Cyanobacteria changed the composition of the atmosphere more oxygen, less carbon dioxide. Direct measurement of co2 concentration in the atmosphere, 1950s to present. Keeling curve shows, overall increase in co2 emissions. Estimate earth"s temperatures for thousands prior to direct measurement. Indicates fluctuations in the past, put dwarfed by massive influx of co2 since. Uv radiation enters the atmosphere, is absorbed by earth then re-radiated as longwave (infrared) radiation. Makes surface temperature warmer than it would be without the atmosphere. Both natural and necessary for life on earth. Greenhouse gases: co2, water vapor, methane, nitrous oxide, cfcs. Emissions rising higher and faster than ever in a short amount of time.
