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Page 1: Climate Change Today

Climate Change Today

1. Is it Really Changing?

2. If so, are Humans the Cause?

Page 2: Climate Change Today

Temperature Change in the Last 1000 Years

Page 3: Climate Change Today

Figure 12.30

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World Temperature Anomaly for 2009Temperature increase is not evenly distributed.

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Minimum Arctic Sea Ice Sept. 1979

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Minimum Arctic Sea Ice Sept. 2005

CERES UC Boulder

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What Did the Snowy/Cold Winter of 2010 in the Eastern U. S. Mean?

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Is carbon dioxide an effective greenhouse gas?

http://www.youtube.com/watch?v=kGaV3PiobYk&feature=related

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Is the level of atmospheric CO2 increasing?

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• Atmospheric CO2 has ranged between 180 parts per million (ppm) and 300 ppm over the past 800,000 years.

• Today, CO2 levels are around 390 ppm.

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The Keeling Curve and CO2 levels since 1958

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Where is the carbon dioxide coming from?

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Table 12.5

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HUMAN-INDUCED INCREASES IN ATMOSPHERIC CARBON DIOXIDE AND METHANE

Carbon dioxide1. Burning of fossil fuels – oil, coal, and natural

gas2. Clearing rainforests and burning the wood

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MethaneMethane is mostly produced by anaerobic

decomposition of organic material.1. Rice paddies2.Cattle raising3.Burning of fossil fuels

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The Vostok Ice Core and how temperature, carbon dioxide, and methane work together.

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• As an ice age ends, temperature starts to rise before either carbon dioxide or methane. Cause: Milankovitch cycles.

• As ocean temperatures rises, its ability to absorb CO2 decreases. Then, CO2 begins to increase in the atmosphere. A positive feedback loop is produced.

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• Methane hydrate in ocean floor sediments begins to melt, releasing CH4 into the ocean and then into the atmosphere.

• Another positive feedback loop occurs.

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Is there agreement among climate scientists about global warming and its cause?

One study found that 97% of climate research scientists agree that…

1. Climate is warming, and 2. Human activities are a significant factor in that warming.

http://tigger.uic.edu/~pdoran/012009_Doran_final.pdf


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