CEE 1030 1nd Edition Lecture 23: ClimateOutline of Last Lecture I. Origin of Earth’s atmosphereII. Atmosphere layersIII. Atmospheric pressureIV. Weather frontsV. Clouds and precipitationVI. Global wind patternsOutline of Current Lecture I. Weather and climateII. Ice AgeIII. Paleoclimatologya. Instrumental recordsb. Historical informationc. Proxy dataIV. Causes of climate changea. Natural causesb. Human causesCurrent LectureI. Weather and climatea. Weather: state of Earth’s atmosphere at a specific place and timeb. Climate: characteristic weather of an area averaged over timec. Regional climate variationi. Climate varies regionally as result of angle of solar radiation, prevailing atmospheric circulation patterns, landscape featuresII. Ice Agea. Pleistocene Ice Age: interval of extensive glaciation starting about 3 million years agob. Evidence of ancient glaciers indicates that ice covered 30% of Earth’s land areac. Evidence of warm intervalsi. Many regions have several layers of glacial deposits, with evidence suggesting glacial intervals were separated by warm, dry climate intervalsIII. PaleoclimatologyThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.a. Paleoclimatology: study and reconstruction of ancient climates and climate changeb. Instrumental and historical records only document climate for the last few centuriesc. More ancient climate reconstructions are based on proxy datad. Proxy data are derived from natural recorders of climate variability (tree rings, etc.)e. Instrumental recordsi. Thermometers and barometersii. Some regions have more extensive documentation than othersf. Historical informationi. Climate change found in historical documents and artworkg. Proxy datai. Most of understanding of Earth’s climate based on natural recorders of climate changeii. Fossil vegetation, tree rings, seafloor sediments, etc.iii. Seafloor sediments1. Shells of small marine organisms2. Different species have different temperature preferences and migrate to track a climate zoneh. Oxygen isotope analysisi. Ratio of oxygen isotopes secreted in organism’s shell, bones, and teeth as it grew is correlated with the extent of glacial ice sheets when the animal livedii. Chemical analysis of shells provides a record of global temperature changei. We are living in an ice ageIV. Causes of climate changea. Natural causesi. Plate tectonics1. Gradual movement of lithospheric plates brings continents closer and farther from the equator2. Distribution of continents and oceans has a major effect on ocean and atmospheric circulationii. Variation in Earth’s orbitiii. Volcanic eruptions1. Explosive volcanic eruptions release ash and gases into the atmosphere, resulting in acid droplets in the atmosphere2. Ash particles reduce solar radiationiv. Greenhouse effect: increased levels of greenhouse gases in Earth’s atmosphere increase the retention of radiated and reflected heat, resulting in global warmingb. Human causesi. Concentration of carbon dioxide increased rapidly in the atmosphere following the Industrial
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