2. Mankind Manmade global warming Pollution Soil degradation (erosion, runoff, etc.) Nuclear warfare Nature Mega tsunami and flooding Large earthquake Hurricanes Drought Super volcano and climate change

3. 10 0 http://library.thinkquest.org/CR0215471/global_warming.htm

4. 10 0 Unzen Volcano Krakatoa explosion Indian Ocean Notable Incidents http://www.tsunami.noaa.gov/

5. 10 0 Overgrazing. Overfarming without crop rotating. Causes Causes land to become unfertile. Was responsible for the American Dust Bowl. http://www.globalchange.umich.edu/glob alchange2/current/lectures/land_deg/land _deg.html

6. 10 0 Shaanxi- Indian Ocean- Could possibly trigger a volanco. http://earthquake.usgs.gov/

7. 10 0 Love canal Radiation Contamination Smog Acid Rain http://edtech.kennesaw.edu/w eb/pollute.html

8. 10 0 Bhola cyclone Indian cyclone http://www.nhc.noaa.gov/

9. 10 0 Sahel drought Sometimes caused by overgrazing "Drought for kids." www.drought.unl.edu. University of Nebraska Lincoln. 26 Jan 2009.

10. 10 0 Hiroshima and Nagasaki Stockpiles Tsar Bomba http://www.howstuffworks.com/ nuclear-bomb.htm

11. 10 0 Krakatoa Tambora Huaynaputina The Year without a summer Volcanic winter Lake Toba

13. "Global Warming." www.thinkquest.org. Thinkquest. 18 Jan 2009. "Tsunami." www.tsunami.noaa.gov. National Oceanic and Atmospheric Administration. 18 Jan 2009. "Land Degredation." www.umich.edu. University of Michigan. 18 Jan 2009. "USGS Home." www.earthquake.usgs.gov. United States Geological Survey. 18 Jan 2009. Jerrie S., Cheek. "Pollution." www.edtech.kennesaw.edu. 8 August 2005. Educational Technology Center. 26 Jan 2009. "Drought for kids." www.drought.unl.edu. University of Nebraska Lincoln. 26 Jan 2009.