GEO 120 Lecture Notes - Lecture 12: Photosynthesis, Permafrost, Milankovitch Cycles
24 Oct 2016
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Geo 120 - lecture 12 - climate change - elizabeth laliberte. Average increase of 1. 5 degrees f over the past 100 years. Many glacial/interglacial cycles over the last few million years. Pleistocene epoch (2 million to 10,000 years ago) 29% of earth"s surface was covered by glaciers. Seal level was 360-460 feet lower than it is today. Changes in positions, shapes, and altitudes of landmass altered ocean (and air) currents. Cyclical changes in the earth"s circumnavigation of the sun. Precession- northern or southern hemisphere face the sun when earth is at its furthest point in annual revolution. When the model is accurate it represents the existing conditions to predict changes that may occur when there is an input change. Carbon dioxide concentration changes in the atmosphere. Photosynthesis- carbon dioxide removed from the atmosphere by plants. Respiration/decomposition- carbon dioxide returned to the atmosphere. Combustion of fossil fuels adds carbon dioxide to the atmosphere.
