gcc_scienceb - ENVST 110 Global Climate Change(Science B...

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ENVST 110 Global Climate Change (Science) B Page 1 of 4 How do we know that temperature and greenhouse gas emissions have increased when we were not around in the distant past to measure them? http://environment.newscientist.com/channel/earth/climate-change/dn11646 Ice cores have allowed us to measure greenhouse gasses in past climates and estimate temperatures. When ice freezes it traps air bubbles that are tiny samples of the atmosphere at the time the ice is formed. Ice is layered in much the same way as geologic sediments, so the deeper you go, the older the ice. We can analyze the air bubbles for greenhouse gas levels to see what was in the atmosphere at that time. The ratio of oxygen isotopes ( 18 O and 16 O) can give us an estimate ( proxy or stand-in measure) of temperature. The temperature measurements are not direct measures like we are able to do now, but they are good estimates that can be checked using more recent data we can collect directly with more recently formed ice. The correlation between temperature rise and rise in CO
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gcc_scienceb - ENVST 110 Global Climate Change(Science B...

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