[QUOTE=Ludovic]
You must be joking. The joke being of course that not only were the coral atolls healthy enough to rebuild themselves (and thus the islands) higher with the rising water level, but also had the luxury of millenia or more to do so.
There very well might be healthy coral in some places of the world, but I doubt that their ability to build up an island several orders of magnitude faster than they ever did before has been proven.
In addition, this sort of harkens to the old canard that just because “mother nature will provide for herself”, and “the EARTH doesn’t need saving,” even IF the islands themselves survive several hundred feet of rising water, human built structures will not (unless the islands float like a preschooler’s conception of them!)
[/QUOTE]
Ludovic, thanks for your post. Having lived up close and personal with coral reefs for a number of years, I can assure you that corals grow plenty fast to stay ahead of the current rate of sea level increase. Coral growth rates have been measured at a reported 280 mm/year in the Andaman Islands in the Bay of Bengal (Sewell 1935), and 414 mm/year in the Celebes (Verstelle 1932).
On the coral atoll where I used to live, we had to go out and clear out the channel into the lagoon every three to five years or so, because the coral had grown up a foot or more, enough to endanger the ships that were entering … and much, much faster than the few mm of sea level rise during that time.
Your statement that there “very well might be areas of healthy coral in the world” simply reveals that you haven’t spent much time in the ocean. I’ve seen dozens and dozens of healthy reefs from above and below the surface, along with some (not a lot, but far too many) that are sick, and some that are dead. My advice would be to stick to subjects where you don’t have to say “there very well might be” …
Finally, there is absolutely no indication that the rate of sea level rise is increasing, or is historically unusual. Perhaps you could provide a citation that shows that the coral will have to grow “several orders of magnitude faster than they ever did”, that’s simply wild exaggeration. There is nowhere on earth that has seen sea level rises of that magnitude, even at the end of the last ice age.
For example, from about 15,000 to 14,000 years ago, during the time identified with “Meltwater Pulse 1a” as the earth came out of the ice age, the sea level rose about 32 metres in about a thousand years. That works out to a rate of about 32 millimetres/year, or about ten times the current rate … and the atolls survived that. But that was as fast as the rise got, ten times the current rate, not a hundred times as you claim.
You are correct that the atolls can only stay above sea level if the coral is healthy, but that is not an argument that the islands are threatened by rising seas. It applies even if the sea level is unchanging, because the surface of the atoll is constantly being eaten away by wind and wave, and unless it is constantly replenished by new coral sand from the surrounding reefs, it will disappear very soon. The rise and fall of the ocean is meaningless, the health of the reef is the issue.
The coral atoll islands are not threatened by changing sea levels, they are threatened by human interference with the health of the corals, through killing fish, through pollution, through killing Giant Tritons, through coral mining for construction and the aquarium trade, and through silt runoff. As a surfer and a diver, I can only agree that humans need to pay more attention to the health of the reefs, you have my full support in that.
And you are correct that human built structures will not rise up with the islands, at least not by themselves … but I’m not sure what your point is there. If you build on an island that goes up and down with the sea level, that’s just an issue you have to deal with, just like builders in California have to deal with earthquakes.
w.
I have no idea what your point is.