1. Long-Term Changes in Climate

2. Studying Climate Change
In studying ancient climates, scientists follow an important principal: If plants or and animals need certain conditions to live in, then similar plants and animals in the past also required those conditions.

3. 3 Ways Scientists Study Climate Change
1- Fossil Records
2- Tree Rings
3- Pollen Records

4. 1- Fossil Records Fossils of plants or animals do not match the current climate.

5. 2- Tree Rings
Thickness of the tree ring indicates the climate. (A thin ring- dry or cool, and a wide ring- warm or wet)

6. 3- Pollen Records
Pollen records (buried under layers of mud) indicate the types of plants that grew in an area thousands of years before.

7. Ice Ages
During each ice age, huge sheets of ice called glaciers covered large parts of the Earth’s surface.
Interglacial Periods- the warm period of time between ice ages
Last Ice Age- Ended about 10,500 years ago
Next Ice Age- 90,000 years? 490,000? Maybe?

8. Causes of Climate Change
Earth’s Position-
to the sun (orbit) or the tilt of the Earth
Solar Energy-
the amount of energy from the sun
Movement of the Continents-
about 225 million years ago Pangaea broke apart and the continents moved to their present positions

9. Checkpoint Question Why were the oceans lower during the ice ages?
Much of the water on Earth was frozen in ice sheets that covered the land.

10. What North America may look like if ALL of the polar ice melts.

11. Interpreting Maps
Which present-day continents broke away from Gondwanaland?
South America
Africa
Antarctica
Australia
India