1. Objectives You should understand how ice forms. You should consider how a glacier operates as a system.

2. Rank the 5 factors in the order with which you think they are responsible for cycles of glaciation and interglacials Changes in the earth’s position in space, its orbit and tilt Variations in sunspot activity, changing the amount of solar radiation received by the Earth Changes in the amount of volcanic dust affecting the amount of radiation reflected and trapped by the atmosphere Trapping of CO2 by the oceans Variations in ocean currents

3. Questions from your reading?

4. Diagrams from text – I read, you draw!

5. Alaskan Valley Glacier

6. How could a glacier be viewed as a system? Outputs INPUTS Transfers Stores Is this an open or a closed system?

7. Describe and explain the patterns on the graph below.

9. How this translates into the glacial system Label your diagram What do the terms net accumulation zone and net ablation zone mean? What is meant by the term Net Glacial Balance? How might this vary over time? How might this vary with location?

11. Review – have a go at the “Assessment on glacial Budgets” sheet