Glaciers and Sea Level

1
Glaciers and Sea Level

• What is the cryosphere?
• What is a glacier?
• History of glaciers
• Glacial Advance and Retreat
• How do glaciers move?
• Effects of Glaciers

2
Glaciers and Sea Level

• What is the cryosphere?
• - The cryosphere is composed of all the frozen
  water on Earth at any given time.
• What are some examples of frozen water on Earth?

3
Glaciers and Sea Level

• Glacier-Thick ice mass that forms over time
• Four types of glaciers
• -Ice Caps
• -Piedmont Glaciers
• -Valley Glaciers
• -Ice Sheets
• Ice Caps cover mountain tops and arctic islands
• Piedmont glaciers occur when one or more valley
  glaciers spread out at the bottom of a mountain
• Valley glaciers can range from several miles long
  to only a few hundred yards long and occur on
  mountain slopes
• Ice Sheets cover all but the highest points of
  the underlying terrain
• The only two ice sheets currently on Earth are
  covering which two land masses?
• Antarctica and Greenland

4
Glaciers and Sea Level

• Brief History of Glaciers
• The Ice Age (Pleistocene) occurred from 1.8
  million years ago to about 12,000 y.a.
• An Ice Age is a period of alternating between
  warm and cold climates occurring roughly every
  100,000 yrs.

5
Glaciers and Sea Level

• Hand out the Glacier Lab Worksheet
• Do the Glacier Lab
• Complete the Worksheet

6
Glaciers and Sea Level

• Glacial Advance and Retreat
• Glacial Advance New ice is forming (colder)
• Glacial Retreat- Ice is melting (warmer)
• How do glacial advances and retreats affect sea
  level?
• Sea level rises during retreat and goes down
  during advance.
• During advances and retreats glaciers dont just
  increase or decrease in size, they actually
  migrate.
• Under current conditions, global sea level rises
  an average of 3mm per year.
• What happens in the RRV nearly every spring?

7
Glaciers and Sea Level

• How do glaciers move?
• Slip and Flow
• Slip happens when a glacier slides or slips
  along a valley or down a mountain. It is how the
  bottom part of a glacier moves and can be slow or
  very sudden.
• Flow occurs in the middle part of a glacier when
  theres at least 50 meters of ice above it. This
  causes the glacier to behave plasticly. (Think
  Silly Putty)

8
Glaciers and Sea Level

• Effects of Glaciers
• Glaciers are responsible for carving many
  features on Earth. Whats one feature in our
  area that can be attributed to glaciers?
• The Red River Valley turned into a flood plain
  after the glacier that made Lake Agassiz melted.
  The valley is scarred from the glaciers that
  scraped along the area before it melted.

9
Glaciers and Sea Level

• Give students the Global Warming worksheet.
• Show the end credits of An Inconvenient Truth