The series explained.

Carbon dioxide is killing the world’s coral reefs in two distinctly different ways. Indirectly, the human-caused build-up of CO2 in the atmosphere has led to global warming, which pushes these fragile ecosystems outside the narrow range of temperatures in which they can thrive.

In 2006, National Geographic put it this way: “Small but prolonged rises in sea temperature force coral colonies to expel their symbiotic, food-producing algae, a process known as bleaching.”

But CO2 kills the reefs directly, too. Because much of what doesn’t end up in the atmosphere is sequestered in the ocean, where it turns the water more acidic. As the Christian Science Monitor reported yesterday, Jeffrey Short, a scientist and environmentalist, told delegates at the Copenhagen conference on global warming that carbon-dioxide emissions should be drastically cut even in the unlikely event that they are not contributing to global warming.

Damage to the coral reefs, the nearest of which are off the coast of Florida, is not theoretical. They are already dead and dying, and some experts believe there’s little chance of their bouncing back. (The Miami Herald reported in 2006 that 90 percent of the reefs in that area had already died.) The reefs are important breeding grounds for fish. According to a study conducted several years ago, National Geographic reports, “fish diversity has tumbled by half in some areas.”

A particularly catastophic event took place in 1998, when a strong El Niño season led to devastating ocean warming. Yes, such natural occurrences show that there are limits to what humans can accomplish. But it also dramatized the effects of long-term, human-caused warming.

As David Adam wrote in the Guardian three months ago:

Within just a few decades, experts are warning, the tropical reefs strung around the middle of our planet like a jewelled corset will reduce to rubble. Giant piles of slime-covered rubbish will litter the sea bed and spell in large distressing letters for the rest of foreseeable time: Humans Were Here.

All this during a week when the World Meteorological Organization reported that the current decade appears to be the warmest on record — warmer than the 1990s, which in turn was warmer than the 1980s. The New York Times reports that the study “largely meshes with an interim analysis by the National Oceanic and Atmospheric Administration in the United States.”

Which brings me back to 1998. Global-warming skeptics such as syndicated columnist George Will are fond of saying that the earth has been cooling since 1998. Essentially what Will and others are doing is pointing to an unusual El Niño year and using it as their baseline. They’re playing a dishonest game, and the new studies make that clear.

All posts in this series.

Photo by Sarah Olmstead (a.k.a. Queen Esoterica) and published here under a Creative Commons license. Some rights reserved.