Coral reefs: The first domino to fall

In 2002, a panel of 17 of the world's leading coral reef researchers warned in an article in Science magazine that "projected increases in carbon dioxide and temperature over the next fifty years exceed conditions under which coral reefs have flourished over the past half-million years." In other words, the conditions under which coral reefs have done well are due to expire in 50 years' time.

They specified: By 2030, "catastrophic damage" will have been done to the world's reefs, and by 2050, "even the most protected of reefs" will be showing "massive signs of damage."

A week ago I read a short article by Roger Bradbury, an ecologist who does research in resource management at Australian National University, in which he bluntly states that "there is no hope of saving the global reef ecosystem." He maintains that overfishing, ocean acidification and pollution are pushing coral reefs into oblivion.

No scientist I've read disagrees with these causes. All three causes have two significant features in common. All three are accelerating, and all three have no real likelihood of changing their trajectories in less than 20 to 50 years. Another way of putting it is to say these forces are unstoppable and irreversible. For example, even though the number of global fish are declining, we continue to accelerate the rate at which we are fishing. Since fish are key to a well functioning coral reef, we are not only fishing out the oceans; we are, at the same time, contributing to the destruction of one of the world's major ecosystems.

Without coral reefs, we will be left with an algal-dominated hard ocean bottom, with few fish but lots of jellyfish grazing on the microbes left by the remains of the limestone reefs. It will be a slimy world down there and will look a lot like the ecosystems of the Precambrian era, which ended more than 500 million years ago - before fish ever evolved.

So, you may well ask, why should we care about Bradbury's grim conclusion on coral reefs?

Bradbury is among those who advocates ecological engineering. He thinks that by "persisting in the false belief that coral reefs have a future," we are wasting money better spent on studies focused on what sorts of ecosystems will replace coral reefs and how these ecosystems might be made to provide people with food and other products. The money he sees as being wasted for a lost cause could also be spent to preserve some of the genetic resources of coral reefs by transferring them into systems that aren't coral reefs. If anything, he feels that we need to deal with the acceleration of those processes that are killing the coral reefs (the high carbon dioxide levels, the acidification and increasing temperature of the ocean, the pollution of nitrogenous nutrients).

It's this latter point that has ramifications for all the ecosystems of our Earth. The global warming that we have produced has given rise to the term "Anthropocene epoch" (man-made environment). It's a sobering, unpleasant thought, and one we don't like to acknowledge.

The trends in species distribution that Camille Parmesan and Gary Yohe of the University of Texas published in 2003 were hailed as a globally coherent "fingerprint of climate change." They include the following: a poleward shift on average of 4 miles per decade; a retreat up mountainsides of 20 feet per decade; and an advance of spring activity of 2.3 days per decade. These trends might seem small compared with the rate of change seen over geological time, but as Tim Flannery, a reknowned scientist on climate change, says, "They are in fact so rapid and decisive, it's as if the researchers had caught carbon dioxide in the act of driving nature poleward with a whiplash."

This is no time to keep our heads in the sand.

• Ursula Carlson, Ph.D., is professor emerita at Western Nevada College.


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