Note: This is a “classic” Interesting Thing of the Day article from over 10 years ago. It has not been edited recently, so it may contain broken links, outdated information, or other infelicities. We plan to eventually update or retire most classic articles, as time permits.

It seems that every time I turn on the TV or open a newspaper or magazine, I see another story about global warming. It’s not only the big environmental issue of the day, it’s one of the big issues, period. Maybe it doesn’t feel quite so frightening or quite so urgent as terrorism or outbreaks of deadly diseases, but certainly it’s right up there. The condensed version of this story—the one that has most thoroughly worked its way into the public consciousness—says that global temperatures have risen much more rapidly during the industrial age than they did before; that they will continue to rise; that worldwide emissions of greenhouse gases such as carbon dioxide are largely to blame for this situation; and that the resulting changes in weather, climate, sea level, and so forth will—sooner or later—be utterly devastating in one or more of several ways. Meanwhile, the United States, which is responsible for some outrageous percentage of the world’s greenhouse gases, is apparently disinclined to reduce those levels, on the grounds that hypothetical long-term problems are outweighed by actual short-term problems such as the extreme inconvenience and cost of reducing emissions.

Burning Rage

Naturally, I’m incensed at all this, especially when I read stories about the apparently imminent disappearance of several entire island nations due to the rising sea levels that are, in turn, a result of global warming. And, assuming that global warming is in fact caused by greenhouse gases (as most people do), it is astonishing that people continue driving gas-guzzling SUVs and smoking cigarettes and, you know, generally showing contempt for the future inhabitants of the planet as a whole and those island nations in particular.

And yet, the reality is much more complex than the sound-byte-friendly version of this problem you hear about on TV. The prevailing notion seems to be that warmer temperatures will melt polar ice caps and glaciers, thus sending more water into the ocean and uniformly raising its level. And though there is a certain amount of truth to that, it is a simplified and misleading picture at best. So I thought it would be interesting to look briefly at some of the facts and controversies surrounding the islands that appear to be sinking into oblivion.

Taking a Dip in the Ocean

The islands most frequently mentioned as being at risk are those closest to sea level. Take the Maldives, for instance—an island nation in the Indian ocean. The highest point in the entire chain of islands is only 2.4 meters (8 feet), and most of the land is much lower. So it doesn’t take much of a change in sea level to wipe out vast amounts of land, and if there’s a bad storm or an unusually high tide, the resulting floods can be devastating—covering the vast majority of the land, fouling fresh water supplies, and wiping out crops. Unfortunately, such floods have been occurring more and more frequently in recent years. The nation’s government has for several years been working on the construction of an artificial island nearby, called Hulhumale, which will be able to serve as a new home for many of the residents if an evacuation becomes necessary.

There’s also Tuvalu, in the Pacific ocean between Hawaii and Australia, with a maximum elevation of 4.6 meters (15 feet). Although the nation has fewer than 11,000 citizens, they are sufficiently convinced of its imminent disappearance that they have already begun to evacuate. New Zealand has agreed to grant “environmental refugee” status to 75 Tuvaluans per year, but according to some estimates, the nation may be entirely covered with water in as little as 50 years. Some of the other island nations most seriously at risk are Kiribati, the Marshall Islands, and Tonga.

Causes and Effects

The evidence that these islands could disappear is fairly plain to those who live there: they’ve seen the waterline move farther and farther inland in the past couple of decades, experienced more and worse storms than previously, and endured flooding that in some cases covered entire islands. And in fact, few people dispute that these nations are in danger to one degree or another (though some would say the danger is rather remote). But it’s tricky to prove the connection to global warming and the further connection to greenhouse gases.

For one thing, even granting that global warming can and does increase sea level to some extent, measuring sea level is a difficult and inexact science—partly because the sea doesn’t like to stay put very long, and partly because any measurement requires a fixed frame of reference (such as land). But the land itself can rise or fall for various reasons, including seismic activity and subsidence due to water table depletion—meaning the appearance of a rising sea level may be due partially to the fact that an island is actually sinking. Furthermore, unusual weather patterns, such as El Niño, can cause dramatic local changes in sea level. Maybe global warming is responsible for the wacky weather and maybe not. But the point is that global warming may be only an indirect cause, or a minor contributing factor, to the shrinking islands.

As for the carbon dioxide connection, that’s also in dispute. Yes, carbon dioxide levels are higher now than in the past; yes, average global temperatures are also higher now than in the past; yes, increased carbon dioxide in the atmosphere can raise the temperature; and yes, human activity produces an enormous amount of carbon dioxide. But some people say that the average global temperature also rose in centuries past when cars and factories could not have been to blame (and then fell again)—causing doubt that human activity is responsible for our current problems.

I find such statements suspiciously convenient, coming as they frequently do from parties that have the most to gain and the least to lose from continued fossil fuel consumption. Be that as it may, none of this changes the fact that more and more of the Maldives finds itself underwater every year. One way or another, the whole situation is rather depressing—especially if you happen to live on one of the islands that is most seriously affected by flooding. By the time the world’s luminaries have reached a unanimous agreement as to whether the planet really is warming up, whether carbon dioxide emissions really are responsible for this problem, and whether we’re collectively willing or able to do anything about it, some of the nations in question may already be long gone. —Joe Kissell

More Information

General articles on disappearing island nations include:

Articles focusing on Tuvalu:

Kiribati is featured in Sinking Feeling by Daniel Williams at Time Pacific, and That sinking feeling at discusses the Maldives.

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Michael Crichton’s latest novel, State of Fear, argues that predictions of global warming and sea level change are seriously overstated and that carbon dioxide has not been shown conclusively to be the cause of such global warming as there is. You can read a rebuttal to many of Crichton’s claims in Michael Crichton’s State of Confusion at RealClimate.