Evidence of Past Climates

1. Evidence of Past Climates

2. Assessing Past Climates • Four key sources of information about past climates: • 1) Tree Ring Data • 2) Ice Core Records • 3) Sediment Cores & Sedimentary Rocks • 4) Fossils

3. Tree “cookie” Tree Ring Data • Every year a tree creates a growth ring • Wet and Moderate Temperatures •  rapid growth  ____________________ thick ring • Dry and Extreme Temperatures •  slow growth  ____________________ thin ring Tree core sample

4. Ice Core Data Ice Core Lab Drilling ice cores in Greenland Studying an Ice Core

5. Ice Core Data • Taken from polar and glacial ice • 800,000 year record in Antarctic ice! • Evidence: • 1) trapped air bubbles • 2) dust, pollen record • 3) Ice chemical composition

6. Sedimentary Rocks and Sediment Cores from Lakes and Oceans • Over1 million year record • Evidence: pollen, chemical • composition of shells

7. Fossil Record • Types and number • of fossil organisms • indicate environment • and climate at time • they were deposited