Regional and Global Climates and Change
10.4 Water World
What did the landmasses look like 20,000 years ago?
Step 1: Go to the ArcGIS Online map, Water World, and explore the map.
The current layer shows an elevation map of Earth as scientists believed it looked 20,000 years ago. At that time, the sea level was 400 feet lower than it is today.
Step 2: With the Details button underlined, click the button, Show Contents. Zoom and pan the map as needed to answer the following question.
- What significant differences do you see between current landmass outlines and those of 20,000 years go?
What would the continents look like if sea levels started to rise?
If the western ice sheets melted, scientists predict that the oceans would rise about 5 meters. If the eastern ice sheet melted, the sea level would rise about 50 meters. If all the ice at the South Pole melted, including all the ice shelve and glaciers, the sea level would increase by 73 meters.
Step 3: One by one, check the boxes next to each Sea Level Increases layer to turn them on.
- Record an observation about each continent as sea levels rise.
How would rivers and lakes be affected by sea-level rise?
Step 4: Turn on all layers except Antarctica Plus 50, Country Outlines, Rivers, and Lakes.
Step 5: Zoom to the South America bookmark.
- What changes do you see in the rivers?
- With a sea-level increase of 50 meters, what kinds of consequences do you foresee for South America’s major river ecosystems?
How would a 50-meter rise affect coastlines and political boundaries?
Step 6: Go to the Southwest Asia bookmark.
Step 7: Turn on the layer, Major Cities data. Toggle between a 50-meter and 5-meter rise in sea level.
- Considering significant changes in the amounts of land remaining in Southwest Asia, which country might be affected by land loss?
Step 8: In the map’s upper-left corner, click the Full Extent button (house).
Step 9: Repeat the process of zooming and identifying potential consequences of the rising sea level for the other major regions.
What would you predict could be the political consequences of a 50-meter sea level rise?
- Predict possible consequences of a 50-meter rise in sea level to the populations living in different areas of the globe.
