Melting Antarctic Ice May Raise Sea Levels Less Than Previously Feared

By Eliza Strickland | May 15, 2009 11:51 am

AntarcticaIf global warming melts the West Antarctic ice sheet, the thick slab of ice that covers an area the size of Texas, the situation for coastal dwellers around the world may not be as dire as previously estimated. A new study, which has sparked some debate, suggests that the water released by West Antarctica‘s melting glaciers would raise sea levels by about 10 feet, not the 15 to 20 feet that had previously been predicted.

While the results sound like good news, Antarctic experts and the study’s lead author, Jonathan L. Bamber of the Bristol Glaciology Center in England, agreed that the odds of a disruptive rise in seas over the next century or so from the buildup of greenhouse gases remained serious enough to warrant the world’s attention [The New York Times]. They also note that some regions would also experience a larger surge in sea levels than others. “Sea level rise is not uniform across the world’s oceans, partly as a result of disruptions to the Earth’s gravity field,” explained Professor Bamber. “It turns out that the maximum increase in sea level rise is centred at a latitude of about 40 degrees along the Atlantic and Pacific seaboards of North America.” This would include cities such as San Francisco and New York [BBC News].

Bamber explains that the world has three ice sheets, Greenland, East Antarctica and West Antarctica, but it is the latter that is considered most vulnerable to climatic shifts. “It has been hypothesised for more than 30 years now that the [West Antarctic ice sheet] is inherently unstable…. This instability means that the ice sheet could potentially rapidly collapse or rapidly put a lot of ice into the oceans” [BBC News]. But in his new study, published in Science, Bamber examined the underlying topography of West Antarctica, and suggests that not all of the ice sheet will collapse. Only those parts that are attached to bedrock below sea level will go, Bamber argues, as warmer ocean water seeps down and melts the glacier where it connects to the rock, allowing the entire mass to slide towards the ocean. Those parts of the sheet grounded above sea level or on bedrock that slopes upwards would remain in place [Scientific American].

But not all glaciologists think it has significantly changed the planet’s immediate prognosis. “The crucial question is how much ice could be lost in the next 100 to 200 years, and Jonathan’s work has not really changed that,” says David Vaughan of the British Antarctic Survey. Most predictions, he says, put global sea-level rise in the coming century at around 1 metre (three feet) – but more will follow [New Scientist].

Related Content:
80beats: Antarctic Ice Bridge Breaks, Hastening the Collapse of an Ice Sheet
80beats: Antarctic Ice Sheet Has Collapsed Before, and Looks Likely to Collapse Again
80beats: A Rising Tide Swamps All Coasts: New Estimates of Sea Level Rise Spell Global Trouble
80beats: Antarctic Ice Melt Would Shift Earth’s Axis, Further Changing Sea Level
80beats: Antarctica Is Definitely Feeling the Heat From Global Warming
DISCOVER: The Ground Zero of Climate Change is the West Antarctic Ice Sheet

Image: flickr / Christian Revival Network

  • Socratic Method Man


    Now we just need to worry about stripping the ozone layer, poisoning the seas and soil and filling them both with plastic granules small enough to enter the food chain, destroying arable land with erosion, killing off pollinating insects with flawed, poisonous organisms from Monsanto, and cutting down the rainforests to grow luxury products for the west to consume.

    Oh, and man’s inhumanity to man.

    I guess we’ll just have to make do with suffocation rather than drowning. There go my plans for the weekend!

  • Ryan

    In the spirit of the Socratic method; could you please provide evidence your rant has any truth in it?

  • YouRang

    Surely the change in the gravity that puts the worst effects at 40^o N is miniscule–an inch or 2.
    And 10 ft rather than 20–big deal. And if (or a significant part) it starts galloping all at once? Landslides cause tsunamis.

  • CaptainElectron

    It would be interesting to see a proposal to build a floating thermal ocean current fence along the West Antarctic coastline. I suspect it could be built a at a fraction of the economic cost of the various greenhouse gas reducing proposals.

  • Michael

    The global warming alarmists continue to backtrack in the face of some real research and real science. The really sad part about this fiasco is that it has severely diminished people’s faith in science and scientists in general, and that’s a pretty unsettling result. The Earth is cooling down–that is a simple, measurable fact. It has been cooling for about 10 years now, and is not warming up. The sea levels are not rising. The glaciers are not melting. The forecasts of doom did not happen. These facts go against the grain of those that are blindly following the global warming hard line, and are making a mockery of scientists and their predictions.

    It’s crying ‘wolf’ very loudly when there is no wolf, and the sheep are multiplying.

  • Erasmussimo

    Michael, claiming that the earth has been cooling for ten years is rather like saying that the economy has been improving for the last 15 minutes. Climate is not weather, and true climatic changes are not apparent over time scales of less than about 30 years.

    And the data clearly show lots of melting of ice in every major environment.

    The forecasts of doom were not made for 2009, so you are like Caesar laughingly saying “The Ides of March are come!” Aye Caesar, but not gone.

  • lilwes

    IM not a member, IM just a kid doing extra credit for my Biology class but I was wondering, what is going to happen to the animals that live on the ice? Where will they migrate to when the ice is all nmelted away?

  • Erasmussimo

    lilwes, there are very few large creatures that live on ice. A number of seals that live on fish will rest on ice, and raise their young in nests in the ice. Polar bears eat the baby seals, so the polar bears need ice. But very few other animals need ice to live on. Penguins, for example, eat fish, but they live in very cold environments. I don’t believe that penguins have to live on ice; they can do quite well on plain old land. So the loss of the ice will not BY ITSELF cause problems for any animals except the polar bears and the seals who nest in the ice. The real problem comes from the indirect effects of the loss of ice.


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