APSC 151 Lecture Notes - Lecture 11: Permafrost, Milankovitch Cycles, Carbon Cycle
7 Oct 2016
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Document Summary
Continued from last lecture, we were talking about earth system science from the perspective of the causes of climate change. We talked about the first example, which was about looking at atmospheric carbon dioxide as part of the carbon cycle. Let"s think about the glacial ice sheets that covered canada 20,000 years ago. In fact, we can recognize from the soil record many glacial/interglacial periods over the last ca. We can compare the atmospheric carbon dioxide variations with the soil/rock record of glacial/interglacial periods: over the last 600,000 years, carbon dioxide levels in the atmosphere correlates with glacial/interglacial periods. When co2 is high, the temperature is high. When co2 is low, the temperature is low. To directly determine past atmospheric temperatures: look at human historical temperature readings. Seems to be mostly from human-produced co2: to determine atmospheric temperature from before the humans were around. Look at oxygen isotopes in the ice cores.
