Ecology and the Environment

What would happen if polar ice caps melted?
Answered by Waleed Abdalati and Discovery Channel
  • Waleed Abdalati

    Waleed Abdalati

  • Discovery Channel

    Discovery Channel

  1. Waleed Abdalati NASA Chief Scientist


    This is what we're working hard to understand, but in the simplest terms, I think most glaciologists agree that the first meter of sea-level rise -- the loss of enough ice and the expansion of the ocean -- is not that difficult to foresee. That's not to say it will happen in the next century, but if it were to happen, not a lot of us would be surprised. Now you start to get to higher levels -- two meters, three meters -- then the consensus or the surprise factor starts to grow. It really isn't clear how much and how fast the ice can change.

    Now, if you do a simple relationship between past temperatures and past sea levels, and just do that straight correlation, it looks like it would be quite a bit over a meter of sea level rise in the next century. But there are lags built into the system, it's very hard to just say, "Well, X degrees last year. Or 500,000 years ago resulted in Y feet or meters of sea level rise, therefore today we can expect that." It's a very complicated system, but what we're seeing in the changes of the ice cover suggests that a meter, three feet, in the next century is not that unlikely. I'm not predicting that, but if it were to happen, most of us wouldn't be surprised. The implications, hundreds of millions of people displaced…

    …coastal communities or many low-lying areas. One estimate (the only one I know of so I can't say whether it's really good or really bad, I'm not cherry-picking it's the only one I know) is about a trillion dollars in expense and loss of property. That's huge, a meter of sea level, but more than that is the humanitarian impact, those people displaced that do not have the tools to adapt are the poor nations -- or are people in the poor nations.

    There are developed nations that could probably handle it -- the United States, we wouldn't like to lose the Florida Keys or much of the Barrier Islands, which most would be inundated or under water, but we could absorb it; it wouldn't be devastating.

    There are some countries in this world where that would just be absolutely devastating.

    More answers from Waleed Abdalati »

  2. If all of the ice that makes up Antarctica at the South Pole melted, sea levels would rise more than 200 feet (61 meters). However, it's highly unlikely this will happen because temperatures never rise above freezing in most parts of Antarctica. At the North Pole the ice is not as thick and actually floats, so if the Arctic Ocean melted, it would not affect sea levels. The ice on Greenland, however, would be more likely to melt because it is closer to the equator and its temperatures are higher. If it melted, it would raise sea levels about 20 feet (6 meters).

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