GEOS 1004 Lecture Notes - Lecture 24: Little Ice Age, Climate Sensitivity, Milankovitch Cycles
8 Mar 2018
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Lecture 24: earth"s climate v: anthropogenic climate change. Earth"s climate is almost never constant, and has been warming since the last ice age. 18,000 years ago, as well as since the little ice age that ended in ~1850 a. d. To say that the global warming of the past century has been anthropogenic, need to demonstrate causality. A potential driver of warming over the past 100 years; greenhouse effect of burning fossil fuels. Greenhouse effect: solar radiation is partially blocked by the atmosphere and is reflected or absorbed by earth. Heat radiates back to space, but this can be blocked by certain atmospheric gases. The more it is blocked, the more heat the atmosphere retains. Blocking infrared radiation depends on molecular structure and concentration. Of the greenhouse effect comes from h2o vapor, the rest from co2 (20%), ch4, n2o, and o3.
