1. Climate Change

2. Natural Processes That Change Climates  Volcanic Eruptions  The presence of volcanic aerosols (ash, dust, and sulfur-based aerosols),CO 2 and water vapor in the air increases the amount of solar radiation that is reflected back into space. This causes Earth’s lower atmosphere to cool. Climate Changes

3. Natural Processes That Change Climates  Ocean Circulation  Changes in ocean circulation also can result in short- term climate fluctuations.  El Niño and La Niña: What are they?  Caused by changes in sea surface temperature (SST) in the equatorial Pacific Ocean  Strongly influence climate around the world  Return every 2 to 7 years but do not always follow each other Climate Changes

4. El Niño Phase Warmer than normal sea surface temperature in the Pacific Ocean near the equator Increase in average rain temperatures in the winter are warmer than normal in the North Central States, and cooler than normal in the Southeast and the Southwest. Fewer Hurricanes Climate Changes

5. La Niña Phase Cooler than normal sea surface temperature in the Pacific Ocean near the equator  winter temperatures are warmer than normal in the Southeast and cooler than normal in the Northwest.  Less than average rain  More hurricanes  More wild fires Climate Changes

6. Natural Processes That Change Climates  Solar Activity  When the sun is most active, it contains dark blemishes called sunspots. The formation of sunspots appears to correspond with warm periods in Europe and North America. Climate Changes

7.  Earth Motions  Geographic changes in Earth’s land and water bodies cause changes in climate.  Changes in the shape of Earth’s orbit and the tilt of Earth on its axis are other Earth motions that affect global climates. Climate Changes

8. Human Impact on Climate Changes  The Greenhouse Effect  The greenhouse effect is a natural warming of both Earth’s lower atmosphere and Earth’s surface from solar radiation being absorbed and emitted by the atmosphere. Climate Changes

9. The Sun’s energy passes through the car’s windshield. This energy (heat) is trapped inside the car and cannot pass back through the windshield, causing the inside of the car to warm up. Example of the Greenhouse Effect

10. Human Impact on Climate Changes  Global Warming  As a result of increased levels of carbon dioxide and other greenhouse gases, global temperatures have increased. This increase is called global warming.  Solar radiation comes in  Some is bounces off the atmosphere  The rest is absorbed by the Earth  It is released as heat  Some of this heat is trapped by greenhouse gasses Climate Changes

11. How Global Warming Works Fossil fuels (coal, oil, natural gas) Carbon Dioxide (CO 2 )