GEOG 1112 Lecture 10: Chapter 10
Document Summary
Climate change: proxy indicator of ice-core data, sediments, coral reefs, ancient pollen, tree-rings. Current: weather station data, remote sensing data, numerical modeling using general. Long-term means millions to hundreds of millions of years. 70 mya: rapid warming, followed by gradual cooling: much warmer in the distant past tropics extended. Generally cooling from 50 mya: theories absorbed carbon dioxide by the himalayas. Short term means the order of hundreds or thousands of years. Carbon isotope analysis: ratio of carbon-12 to carbon-13 and carbon-14, each decompreses by half-life, the time it takes for half of the sample to undergo radioactive decay. Tree-ring: annual growth bands, wider rings suggest good growing conditions. Other sources: cores taken from lake sediment, pollens, fossils, charcoal, limestone formations in caves, corals. Pleistocene epoch began 2. 5 million years ago. Last glacial period lasted from 110,000 years ago to about 11,700 years ago.
