Arctic Meltdown

The U.N. report this year suggested a sea-level rise of 20 to 60 centimeters [in this century]. Now scientists seem to be talking about much more dramatic sea-level rises.
The IPCC report released in the last several months is based on models that account only for thermal expansion of the water. As the ocean warms, the only thing it can do is expand and contribute to sea-level rise. The report does not explicitly include estimates of the amount of melt water that will drain from places like the Greenland ice sheet and the peninsula region of the Antarctic and from land-based glaciers. What we've seen over the last couple of years is a rapid change in land-based glaciers, particularly in Greenland. I think most of us are suggesting that we'll see up toward a meter in sea-level rise by the end of this century. And that includes a combination of melt-water drainage from land-based glaciers and ice sheets and continued thermal expansion of the ocean.

Which regions of the world will be affected most catastrophically by that?
I'm deeply concerned that people don't really don't understand the urgency. The coastlines of the entire world have been battered by storms for centuries. As sea levels rise, the sea marches inward. The scientific projections are estimating up to one meter of sea-level rise in this century, but one must add to this the inundation of inland areas caused by increasingly severe storms. Land that has not been hardened by the continuous bombardment of storms will be newly exposed. In Florida, for example, the inundation process roughly triples the amount of land lost to one meter of sea-level rise. Just draw a line from Miami west across the state, and everything south of there is going to be gone, flattened, underwater. Only a third of that is less than one meter; all the rest is inundation, because it's very low lands. In the Chesapeake Bay, where I live, the remaining islands will all be gone. In Maine, very little effect: Maybe the Rachel Carson preserve will be gone and that's about it.

What do we know about the immediate effects when the great ice sheets melt? There have been reports that there have been more earthquakes in Greenland.
First of all, I don't think it can be demonstrated that there are more earthquakes. But there are increasing "ice quakes," because as that massive amount of ice tries to adjust itself to the topography of all the land and granite, it breaks up. And sometimes there are big breaks. There was some press about this and maybe a copy editor changed "ice" to "earth." But the ice quakes are increasing. There is another important process underway. As the melting process occurs in Greenland, the cracks in the ice which we didn't think went all the way to the bottom do, in fact, go all the way to the bottom. So the drain water finds its way through these cracks and crevices. Give it a little time and it opens up a hole called a moulin. The hole might be 10 feet in diameter. Many rivulets of water converge and form an incredible cascade of water that looks like a waterfall—a roaring mass of water cascading down the moulin to the base of the glacier. It goes all the way to the bottom and does two things to the ice. First, there's the buoyant force of the water pushing up underneath the ice sheet, making it easier for the glacier to move. And second, the water lubricates the flow and further facilitates the glacier's flow toward the sea.

Beyond the rising sea levels and flooding, what are the other effects of melting glaciers?
Many people are very likely to be displaced. Several scientific papers suggest that one meter of sea-level rise will probably mean that somewhere on the order of 150 million people will be displaced from their homes or homelands, in places like Bangladesh. We're going to have what people are calling environmental refugees. This will have a profound impact on foreign policy and national security issues.

What are the other effects on nature itself? How does melting affect the Gulf Stream? What are the effects on wildlife or fisheries?
There's no question that fresh water going into the North Atlantic will probably have a minor near-term effect—certainly on the time scale of 100 years—on oceanic circulation. The scientific consensus, I believe, is that it's not likely to shut down that conveyor belt of the Gulf Stream. But I think probably the biggest effect is the impact on the biological species across the Arctic and, in time, globally. The warming and the changes in precipitation will cause ecosystems to be disrupted. The projections are that some of the ecological systems won't be able to sustain themselves. Another likely problem is water. There is probably going to be an increase in conflicts about water, because we are going to see more droughts, more floods, and a redistribution of the way water is available on the planet. In short, as the planet gets warmer, things are going to happen more dramatically, more rapidly, or in some cases more intensely. That will contribute to floods, for example, because the river and drainage systems [won't be able to] absorb water from rain that comes much more intensely. During the past several decades in the U.S., the amount of rain falling at rates of about two inches per hour has increased by 30 percent or so. I think some of the floods we've seen in recent times are early evidence of this climatic effect.

What do you think needs to be done?
I've adopted an idea I call "the climate cathedral strategy." When Notre Dame was built, it took 100-plus years. When the masons laid the foundation, they had no idea what the gargoyles or the buttresses would look like. The character of the cathedral evolved as construction proceeded through a continuous, correcting process, taking advantage of past experience, new insights and other factors. But you didn't build that cathedral until you had a foundation. We need to build the foundation for building the climate cathedral. The just-completed negotiations in Bali are one step in that direction. [But] unless there is a sense of urgency and full implementation [of the agreement] in the next couple of years, the world is likely to experience the consequences of an accelerated warming of the planet. The impacts of that are likely to be challenges to human well-being, economic stability and international security.

© 2007