1. Long-Term and Short-Term Changes in Climate

2. The Earth is 4.54 billion years old
In it’s history, there have been many natural variations to it’s climate
These change have occurred due to changes in how energy is absorbed and trapped by the Earth

4. For example…
Ice Ages
a period in Earth’s history where the Earth is colder and much of the planet is covered in ice

5. Long-Term Changes are due to:
Continental Drift
According to plate tectonics, all of the continents have been moving and are continuing to shift their position on the Earth’s surface
How it impacts climate?
Changes ocean currents and wind patterns
Changes how land masses are distributed which reduces the effect of local bodies of water on climate
Creates mountains which affect climate

6. Video

8. Cycles in Climate
Long term cycles (over tens and hundreds of thousands of years) occur alternating between ice ages and warmer interglacial periods
Theories on why the climate changes:
Shape of the orbit changes over time
Earth’s tilt changes and wobbles

9. Short-Term Changes are caused by:
Volcanic Eruptions
When an eruption occurs, rocks, dust and gas are shot high into the atmosphere
These particles reflect the suns rays and lower the energy transmitted to the Earth

10. Changing Ocean Currents
El Nino – a recurring change in the Pacific winds and ocean currents that brings warm, moist air and water toward South America instead of Africa

11. Changes in the Sun’s Radiation
If the amount of radiation from the Sun drops, the Earth receives less energy and cools
Scientist’s are constantly monitoring the Sun’s energy output

12. Homework
Pg 353 # 2, 4, 5, 7