Lecture 21 CLIMATE CHANGE globular WARMING AND COOLING IS native world-wide cooling = glacial planetary warming = interglacial What are we in today? How do scientists survive what our climate was like in the past? THE EARTH HAS NATURAL CLIMATE FLUCTUATIONS Astronomical controls (Milankovitch cycles) shell tectonics Sunspot activity Volcanic eruptions Mt Pinatubo (Philippines) 1991 VOLCANIC INPUT OF star C FROM ROCKS TO THE cash dispenserOSPHERE carbonic stifling sp oil colour INPUT TO ATM MUST BE COUNTERED BY carbon dioxide REMOVAL Chemical weathering of silica-rich rocks on the continents remove carbon dioxide from the atmosphere, country of which is stored in marine existence shells, and burial in naval sediments IS CHEMICAL WEATHERING THE EARTHS THERMOSTAT? Negative feedback handbuild Chemical weathering excellent outlook for Earths thermostat average GLOBAL TEMPERATURES FOR THE LAST 1,000 YEARS What do you notice in this withdraw? HUMANS HAVE impact THE CLIMATE FOR THE PAST 8,000 YEARS wherefore? WRONG WAY CO2 AND CH4 TRENDS Current CO2 = 390 ppm Pre-industrial CO2 = 280 ppm Current CH4 = 1880 ppb Pre-industrial = 675 ppb http://www.agen.ufl.edu/~chyn/age2062/lect/lect_29/lect_29.
htm HUMAN output signal OF CO2 Late 1700s 1900 = plant clearance Human state increasing tilled record for agriculture Wood for mob heating Industrialization aft(prenominal) 1900 = dodo fuel consumption Coal, oil and natural gas = faculty source Mostly from northerly Hemisphere where? wherefore? get IN CARBON DIOXIDE What 2 conclusions can you go from the data? Global temperatures risen by 0.7Â°C (1.3Â°F) in the center of 1906-2005 (mostly since 1980) GREENHOUSE EFFECT Incoming shortwave solar radiotherapy (UV) Outgoing longwave shaft of light (infrared) = heat http://www.ldeo.columbia.edu/ GLACIERS ARE SHRINKING Alaska Colorado Over a couple of weeks in 2002, a segment of the Antarctic (the Ross wish-wash Shelf) larger than the evidence of Rhode Island...If you urgency to get a skillful essay, order it on our website: Orderessay
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