ERTH 2415 Chapter : ch 11 pt 1.docx
14 Mar 2012
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Document Summary
Human activities have added to the increase in global surface temperature rising see previous chapter 10. Natural greenhouse effect strength has varied over the years. We"re changing our climate despite growing concerns. 60% of greenhouse warming caused by humans comes from releasing carbon dioxide into the atmosphere through burning oil, natural gas, coal, and wood, as well as clear cutting forests. How does carbon cycle through the environment: co2 is removed from the earth/atmosphere by plants during photosynthesis to build tissue, plants die organic tissue is oxidized and co2 returns to the atmosphere and dissolves in water. Humans have disrupted the carbon cycle by decomposing plants at increasing rates = increased co2. In 1800, co2 in atmosphere = 280 ppm, in 2006, co2 in atmosphere = 382 ppm. This is an increase of 35% with an increase of 70% since 1950. Clearing land for agriculture, heat homes, and charcoal to burn.
