Coastlines After Ice Collapse

Scientists think there is just a one in 20 chance that the West Antarctic Ice Sheet (WAIS) will collapse in the next 200 years. The WAIS is crucial to future sea levels, because if all the ice melts in this region, it could raise ocean levels by several feet.

The West Antarctic Ice Sheet contains about 13% of all the ice in Antarctica, and scientists believe it melted about 120,000 years ago when temperatures were warmer than they are today. In parts of the West Antarctic, temperatures are now rising much faster than they are in the rest of the world, and the researchers involved in the UK study have concluded there is now a one in 20 chance in the next two centuries of the ice sheet once again collapsing.

Lead scientist Dr. David Vaughan, of the British Antarctic Survey, says, ?Although this study shows the probability of ice sheet collapse is reasonably low, there?s a huge health warning attached. The potential impacts of a major change in the West Antarctic Ice Sheet are severe – fantastically expensive for developed nations with coastal cities, and just dire for poor populations in low-lying coastal areas. This is the first time a risk assessment of ice sheet collapse has been attempted and it is the best estimate we can make based on the current information. More data on the ice sheet is urgently required to be more certain about the future of the ice sheet and possible future sea-level rises.?

The research concluded that ocean rises would be spread out over at least several centuries and probably much longer. It would be at most a 3 foot rise per century, which is about five times the current rate of sea-level rise.

The report says, ?If this occurred, it would be slow enough for a managed retreat from low-lying coastal areas, and a progressive raising of flood defenses around populated areas. However, this would be expensive. Economists estimated a cost of 0.1% of gross domestic product for many nations such as the U.K., but it would be much higher for smaller island states.?

What would happen to the world?s coastlines if the West Antarctic Ice Sheet melted, raising global sea levels by as much as 200 feet? Click below to get a look at selected coasts in the aftermath of such a melting (black lines represent current coastlines). To play it safe, these images depict a conservative rise of 170 feet.

You can also see the same stretch of coastline as it appeared 20,000 years ago at the height of the Ice Age, when sea levels were 400 feet lower than today.

Here?s what you?ll see:

U.S. East Coast 20,000 years ago (400 feet below today) U.S. East Coast if West sheet melted (17-foot rise) U.S. East Coast if East sheet melted (170-foot rise)

Florida 20,000 years ago (400 feet below today) Florida if West sheet melted (17-foot rise) Florida if East sheet melted (170-foot rise)

Northern Europe 20,000 years ago (400 feet below today) Northern Europe if West sheet melted (17-foot rise) Northern Europe if East sheet melted (170-foot rise)

Southeast Asia 20,000 years ago (400 feet below today) Southeast Asia if West sheet melted (17-foot rise) Southeast Asia if East sheet melted (170-foot rise)

To see images,click here.

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