CEE 1030 1nd Edition Lecture 23 Climate Outline of Last Lecture I Origin of Earth s atmosphere II Atmosphere layers III Atmospheric pressure IV Weather fronts V Clouds and precipitation VI Global wind patterns Outline of Current Lecture I Weather and climate II Ice Age III Paleoclimatology a Instrumental records b Historical information c Proxy data IV Causes of climate change a Natural causes b Human causes Current Lecture I II III Weather and climate a Weather state of Earth s atmosphere at a specific place and time b Climate characteristic weather of an area averaged over time c Regional climate variation i Climate varies regionally as result of angle of solar radiation prevailing atmospheric circulation patterns landscape features Ice Age a Pleistocene Ice Age interval of extensive glaciation starting about 3 million years ago b Evidence of ancient glaciers indicates that ice covered 30 of Earth s land area c Evidence of warm intervals i Many regions have several layers of glacial deposits with evidence suggesting glacial intervals were separated by warm dry climate intervals Paleoclimatology These 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 IV a Paleoclimatology study and reconstruction of ancient climates and climate change b Instrumental and historical records only document climate for the last few centuries c More ancient climate reconstructions are based on proxy data d Proxy data are derived from natural recorders of climate variability tree rings etc e Instrumental records i Thermometers and barometers ii Some regions have more extensive documentation than others f Historical information i Climate change found in historical documents and artwork g Proxy data i Most of understanding of Earth s climate based on natural recorders of climate change ii Fossil vegetation tree rings seafloor sediments etc iii Seafloor sediments 1 Shells of small marine organisms 2 Different species have different temperature preferences and migrate to track a climate zone h Oxygen isotope analysis i 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 lived ii Chemical analysis of shells provides a record of global temperature change i We are living in an ice age Causes of climate change a Natural causes i Plate tectonics 1 Gradual movement of lithospheric plates brings continents closer and farther from the equator 2 Distribution of continents and oceans has a major effect on ocean and atmospheric circulation ii Variation in Earth s orbit iii Volcanic eruptions 1 Explosive volcanic eruptions release ash and gases into the atmosphere resulting in acid droplets in the atmosphere 2 Ash particles reduce solar radiation iv Greenhouse effect increased levels of greenhouse gases in Earth s atmosphere increase the retention of radiated and reflected heat resulting in global warming b Human causes i Concentration of carbon dioxide increased rapidly in the atmosphere following the Industrial Revolution
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