1. Climate changes Earth is constantly changing, including the climate.
There are two causes of climate change:
Natural processes include
volcanic eruptions,
ocean circulation,
solar activity, and
Earth motions.
Human impacts include
the greenhouse effect and
global warming.

2. Volcanic eruptions Volcanoes -> large amounts of ash and gases
Clouds can block out the sun’s radiation and cause a cooling of Earth (Year With No Summer)
Climate changes are temporary.

3. El Niño
El Niño ( Southern Oscillation) – unusual warming of the eastern tropical Pacific Ocean.
High- and low-pressure systems flip-flop between the eastern tropical Pacific and the western tropical Pacific.
Occurs around Christmas time and is named for the “The Boy” (in reference to “Christ Child”).

4. Weather Conditions
Normal weather patterns include strong westerly winds and upwelling along the South America coast.
During El Niño, weather patterns do not have the strong westerly winds, causing the upwelling to disappear.

5. Weather Changes
Indonesia and Australia – normally have large amounts of rain, go into a drought during El Niño.
North and South Americas – normally dry, have a lot of rain- and snowfall.
El Niño can also cause severe and extreme weather events, such as typhoons and tornadoes in unusual locations.

6. Weather Changes in the United States
Western and Southern states – above normal rainfall.
The Southern states – cooler than normal temperatures.
Note: The number of hurricanes hitting the Caribbean and North America is decreased.
The Western states (especially California) – most severe weather impacts, such as torrential rains, flooding, and mudslides.
Alaska, the Northeast, and the Pacific Northwest – warmer than normal.

7. La Niña
La Niña (“The Girl” – opposite of “The Boy”) –cooler than normal temperatures in the tropical Pacific Ocean.
In the United States – winters tend to be warmer, summers tend to be cooler than normal

8. Solar Activity
When the sun is most active – contains sunspots (dark spots) on the sun (more solar radiation)
Increase in number of sun spots – temperatures in North America and Europe increase
No evidence of long-term climate changes

9. Earth Motions
Plate tectonic movement – long-term climate changes by changing size, location, and shape of water basins and changes in the geographic position.
Changes in the shape of Earth’s orbit and the tilt of Earth on its axis – short-term and long-term changes.
Stretching  push Earth farther from the sun
Shortening  bring Earth closer to the sun
The changes in the tilt of Earth’s axis – controls the seasons.

10. Greenhouse Effect
Water vapor and carbon dioxide – major greenhouse gases
Water vapor and carbon dioxide – trap heat in our atmosphere that would normally be radiated back into space
Without the greenhouse gases, Earth would be too cold to live on
Humans impact the greenhouse effect
increasing the amount of carbon dioxide which causes temperatures to increase beyond the normal amounts

11. Global Warming
Global warming – increase in global temperatures from an increase in carbon dioxide
Average global temperatures have increased 0.6oC in the 20th Century; are expected to increase by oC by the year 2100.
Will lead to the melting of the glaciers, higher ocean water levels, increased evaporation rates.
These events lead to lower albedo  even higher temperatures
Increases in number and intensity of hurricanes, more intense heat waves and droughts, and many more

12. Earth’s Temperatures
Temperatures in the Northern Hemisphere from 200 A.D. – 2000 A.D.
At the start of the Industrial Revolution – temperatures began to rise and have continued

13. Assignment
Hurricane Tracking Activity
Fill-in Video Questions