ENV100Y5 Lecture Notes - Lecture 46: Lake Suwa, Ice Core, Dendrochronology
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ENV100Y5 Full Course Notes
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Document Summary
Instrumental record - we were there; about 150 years. Deep drive - geologic record through sediments, fossils; about 100 millions and billions. Proxy indicators = controlled by or mimic climate, and substitute for direct measurements. Glacial ice holds clues to past climates. Trapped bubbles in ice cores preserve actual atmospheric composition. Ice core layering reveals temperature trends, snowfall, even fires and volcanic eruption sounds. Climate proxies provide a record of past climates. Human records of events or processes that are controlled by climate, such as: Weeks of sea ice off the coast of iceland. Medium-term climate proxies (100s to 1000s of year): Natural processes cause stable isotopes to become separated or fractionated, and differentially concentrated in different material. Isotopic analysis of ice cores is the most important source of paleoclimate data. Longer-term climate proxies (1000s to millions years): The paleoclimatic record from ice cores now extends back 800,000 years (epica.
