Every so often comes news of islands just up and disappearing. Eight in Micronesia. Five in the Solomon Islands. One off the coast of Hokkaido, Japan. Yet there’s also been a crop of studies and researchers, led by coastal geomorphologist Paul Kench from Simon Fraser University, saying that island nations such as Tuvalu (long a poster child for the existential threat of sea level rise) not only aren’t disappearing—they’re actually growing. So how do we make sense of this? Are the low-lying islands we know today doomed? Or are we seeing some other process at work? The answer is that a million complicated things are happening all at once, and it provides a window into how hard it is to talk about what’s currently happening to the planet….
One big culprit that comes up when we talk about disappearing islands is sea level rise, of course. The Sea level was, for a few thousand years up to around the late 19th century, pretty constant, on average. Since the late 1800s, it’s been steadily rising. On average.We keep saying “on average” because sea level changes are not the same in all places. In fact, in a lot of places, the sea level is dropping.… The single largest cause of global sea level rise, right now, isn’t melting glaciers, but the phenomenon called thermal expansion. Thermal expansion is the tendency of matter, including sea water, to change its volume in response to a change in temperature… Global temperatures have risen by about 1.4 degrees Fahrenheit since 1880, with most of that in the last half-century. And that means the water already in the ocean is getting bigger…
Yes, all of this is going to have a major impact on any low-lying land the world over. But the researchers I talked to for this story don’t necessarily think that islands are disappearing right now at a higher rate than they were in past centuries. Of the independent island nations most at risk of disappearing, Tuvalu is near the top of the list. But a 2018 Paul Kench study of all 101 islands—all small and low-lying—that make up Tuvalu reported that there’s no consistency in what is happening there at all. About three quarters of the islands actually grew in size, to one quarter that shrank, over the past 40 years. Overall, during this time period, Tuvalu grew almost three percent. This is not to say that Tuvalu isn’t in a period of intense crisis right now, because the country certainly is. But disappearing—which is a very specific thing—might not be the cause of that crisis, at least not today…. [It is imporant] to realize that the impacts of the direction that global climate is headed in are simply not going to be the same everywhere.
Paul Kench’s work—which ran counter to the narrative that the days of the low-lying, habitable islands that we know are gone—angered some, who see it as unhelpful to the very real plight of Tuvalu and other South Pacific island nations. But Kench notes that the mere disappearance of some islands shouldn’t be the whole story. Those harsher and more frequent storms send waves of salt water inland—sometimes over entire islands, sometimes into fields, or into fragile island freshwater sources. Homes and infrastructure are at risk, as are the unusual plant, insect, and bird species found on small islands and nowhere else. Scientists are already exploring simply moving endemic species to more stable islands.
Excerpts from DAN NOSOWITZ, How Alarming Is It That Islands Are Just Disappearing? Atlas Obscura, Mar. 2019