GEOG 2800 Lecture 15: Paleoclimates.pdf
5 Mar 2015
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Document Summary
Earth"s average surface temperature during last 4. 6 billion years. Know more in recent past than we do in far past (obviously) Last 500 million years some serious fluctuation. Current global warming is just a small "blip" in the grand scheme of things. Earth is slipping into colder and colder regimes. Ice ages only started occurring relatively recently. May reach a stage of permanent glaciation in canada in future if co2 emissions continue at the rate they are going. First years earth was still trying to cool off from mass amounts of energy released during the collapse that formed the planets. Atmosphere is a result of "out gassing" from earth"s interior. Bacterial life can get started very quickly (single-celled organisms) Era starts with oldest rocks and ends with increase of oxygen in atmosphere. Early atmosphere primarily co2 and ch4 causing strong greenhouse effect. Solar output was weaker so overall temps were not outrageously hot.
