GEOL 213 Lecture Notes - Lecture 29: Greenhouse Gas, Smog, Tide Gauge
21 Nov 2020
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Document Summary
Like many measurements of the environment, precise measurements are only a recent (~200 years or less) development. Accurate thermometers were first made in 1714 (fahrenheit). However, not until ~1850 were there enough weather stations to produce a global record. Geologically preserved materials from which climate information can be extracted. Ice cores glacial ice chemistry is related to temperature of snowfall; air bubbles allow ancient greenhouse gases to be measured. 2013 study used a series of climate proxies to estimate temperature change over past. Results suggest earth was getting cooler (start of new ice age?) over past ~6000 years and began to warm again during past ~250 years. Plant growth rates are closely related to both temperature and rainfall conditions; i. e. , trees generally grow faster when it is warmer and wetter. However, it is difficult to tell whether colder or dryer (or both) conditions created poor growing conditions.
