ENGAGE
Glacier Ice--Sea Level
It is estimated that sea-level could rise as much as 80 meters if all land ice melted and returned to the sea. How would you estimate the distribution of glaciers effects:
- If all of Alaska's glaciers melted, sea level would rise ~ _____ meters.
- If all of Greenland's glaciers melted, sea level would rise ~ _____ meters.
- If all of Antarctica's glaciers melted, sea level would rise ~ _____ meters.
(Find answers at USGS Glaciers and Sea Level)
Glaciers have been melting for many thousands of years. And sea-level has been rising for thousands of years. And we're arguably better off without continental icesheets sprawling over northern Europe, Asia and North America. But, as it turns out in so many cases, timing is everything.
The gradual pace of change over many generations can create a lulling effect. Changes which occur slowly over many years often go little noticed and can be more easily adapted to. Thousands of years ago, people and their settlements were able to move in gentle response to gradual sea-level dynamics. And thousands of years ago people were more accustomed to moving around in response to resource availability anyway.
However, not all change is gradual. And as we are now learning, many of the variables that cause climate change often have associated positive feedback mechanisms which dramatically alter the rates at which changes occur. And some changes are further compounded by specific physical thresholds which can trigger immediate and profound effects.
For example, gradually warming ice stays solid, but only up to a certain point--then it becomes a liquid, rapidly. The increased rate of melting of continental ice sheets or glaciers, and the resulting influx of enormous quantities of fresh water formerly stored on land, causes, among other things, a corresponding rapid increase in sea-level.
And this is a concern for many low-lying areas across the much of the planet. Many coastal areas, unlike those of our more mobile and nomadic ancestors, are highly capitalized and densely populated. Miami, New Orleans, and Venice Italy just to name a few on the list of large cities at great risk for increases in sea-level.
Glaciers have been melting for many thousands of years. And sea-level has been rising for thousands of years. And we're arguably better off without continental icesheets sprawling over northern Europe, Asia and North America. But, as it turns out in so many cases, timing is everything.
The gradual pace of change over many generations can create a lulling effect. Changes which occur slowly over many years often go little noticed and can be more easily adapted to. Thousands of years ago, people and their settlements were able to move in gentle response to gradual sea-level dynamics. And thousands of years ago people were more accustomed to moving around in response to resource availability anyway.
However, not all change is gradual. And as we are now learning, many of the variables that cause climate change often have associated positive feedback mechanisms which dramatically alter the rates at which changes occur. And some changes are further compounded by specific physical thresholds which can trigger immediate and profound effects.
For example, gradually warming ice stays solid, but only up to a certain point--then it becomes a liquid, rapidly. The increased rate of melting of continental ice sheets or glaciers, and the resulting influx of enormous quantities of fresh water formerly stored on land, causes, among other things, a corresponding rapid increase in sea-level.
And this is a concern for many low-lying areas across the much of the planet. Many coastal areas, unlike those of our more mobile and nomadic ancestors, are highly capitalized and densely populated. Miami, New Orleans, and Venice Italy just to name a few on the list of large cities at great risk for increases in sea-level.
EXPLORE
Teachers' Domain
If the Ice Melts, is a TD interactive resource that demonstrates graphically how sea-level has changed in the past 20,000 years, as well as predicted changes as more terrestrial ice melts and returns to the sea.Here's a
nother in our exciting series of science activities,
Watching Ice Melt!
Drip...Drip...Drip....
Information is Beautiful
Take a look at this creative and informative portrayal of endangered coastal cities, time, sea level changes, causes and coastal profiles all in one attractive and accessible graphic.
Information is Beautiful.
EXPLAIN
nother in our exciting series of science activities, Watching Ice Melt!
Drip...Drip...Drip....
- Partially fill a suitably large glass container with water so you can see sea level.
- Mark sea level on the side of the container with tape or a marker.
- Suspend several ice cubes in a screen, sieve, mesh, cheesecloth or food colander so that melt water drips directly into the glass container.
- Observe changes in sea level as ice melts.
- For effect, try placing a facsimile "sea level city" in the container at the start.
Information is Beautiful
Take a look at this creative and informative portrayal of endangered coastal cities, time, sea level changes, causes and coastal profiles all in one attractive and accessible graphic.Information is Beautiful.
EXPLAIN
- How does Florida's coastline compare relative to a sea-level changes?
- What cities are most vulnerable to sea level rise?
- How is the effect of melting terrestrial ice on sea level different from that of melting sea ice?
EXTEND
EVALUATE
- Find out why isostatic rebound causes sea-level to drop near Glacier Bay .
- Use Google Earth to explore 200 years of glacial recession in Glacier Bay.
- Try adding the Extreme Ice Survey layer to your Google Earth menu of features.
EVALUATE
- How important is the issue of sea level rise?
