GEOG 205 Lecture 5: Module1B
31 May 2016
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Document Summary
The role of climate changes in the past have in modern climate changes, help make predictions about the future. Study of past climates, obtained from proxy indicators (indirect evidence used to infer past climate) Utilizes chem, physics, geology, atmospheric, ocean sciences, history,, anthropology, archaeology. Isotopes: atoms of the same element with different number of neutrons, same protons & electrons. Depending on the climate, % of 2 types of oxygen (o16, o18) varies in water. Ratios of heavy o18 to o16 oxygen isotopes influence mainly by processes involved in the hydrologic cycle. Ratios change, these changes are proxy to changing climate. Scientists compare ratios in ice cores, sediments, or fossils. Tree rings (dendrochronology): analysis of growth ring patterns, determine the associated climate. Pollen analysis: pollen resistant to decay, climate change = different assemblage of plant species, what kind of plants grow in certain climates. Large scale climate changes associated with plate tectonics and its influence on atmospheric greenhouse effect.
