1. Natural Causes of climate change

2. Volcanic eruptions Volcanic eruptions eject tons of SO 2 and ash into the atmosphere. These substance reflect solar radiation back into space resulting in global cooling.

3. Orbit around the sun Three aspects of earth’s orbit affect climate: eccentricity, precession, and tilt. Eccentricity – the shape of earth’s orbit

4. Earth’s tilt on its axis causes seasons.

5. Precession – how much earth wobbles on its axis.

6. Solar output About every 11 years the sun goes through a period where it emits more energy than normal through solar flares and electromagnetic storms. During the peak of the “Little Ice Age (1350-1850) the Maunder Minimum was a large dip in solar activity from 1645-1715. During that time there was almost no sunspot activity.

7. Other possibilities At the end of the ice ages a crack in an ice sheet released tons of natural gas causing an abrupt rise in temperature. There is solid evidence that warming-induced changes in ocean circulation at the end of the last Ice Age caused vast quantities of ancient carbon dioxide to belch from the deep sea into the atmosphere. Scientists believe the carbon dioxide (CO2) releases helped propel the world into further warming.

8. Short Term Climate Change – El Nino http://video.nationalgeographic.com/video/ el-nino http://video.nationalgeographic.com/video/ el-nino

9. References http://www.nc- climate.ncsu.edu/edu/k12/.SolarCycles http://www.nc- climate.ncsu.edu/edu/k12/.SolarCycles http://news.mongabay.com/bioenergy/200 7_05_12_archive.html