TCS Daily


Beware Reef-er Madness at Marrakech Climate Conference

By Sallie Baliunas - October 29, 2001 12:00 AM

As U.N. climate talks enter a third round in 12 months at Marrakech in Morocco this week, look for those favoring the flawed Kyoto Protocol proposal for sharp curbs on industrial nations' carbon dioxide emissions to latch on to a hyped story to press their cause.

The issue is coral reefs, the sea's rainforests so vital for fisheries, coastal protection and, because of their great beauty, tourism. And The United Nations Environmental Program recently announced the most detailed assessment of reefs' health yet.

The new UNEP Atlas claims 58% of the world's coral reefs is threatened by human activities like dynamite fishing, local pollution and global warming. According to the Australian Institute of Marine Science, which provided much of the groundwork for the UNEP report, 27% of the world's coral reefs have been lost, "with the largest single cause being the massive climate-related coral bleaching event of 1998."

But a close examination of the basis for blaming human-made global warming for the loss of coral reefs - and posing a huge threat to them in the future - lacks substance. And at a practical level, the overly heavy focus on human-induced warming as the source of reef degradation may damage other worthy efforts to protect coral reefs.

The UNEP story begins with some pessimistic puffery claiming coral reefs occupy a "smaller area of the planet than previously assumed." All that has really happened, though, is welcome progress in reducing ignorance about the scope of reefs.

UNEP's latest assessment claims 284,300 square kilometers of reefs exist worldwide, or 110,000 square miles. Now, several measures of the size of coral reefs around the globe have been made, and they've yielded a wide range of results -- from 100,000 square kilometers to nearly 4,000,000 square kilometers, depending on how reefs are defined. Taking the high-end estimate, it could appear that reefs are disappearing.

But UNEP had a decent baseline set four years ago, when Mark Spalding, the co-leader of the UNEP's global assessment effort, estimated the area for coral reefs as 255,000 square kilometers. So on that basis, coral reefs now occupy 29,000 square kilometers more area than previously thought. So UNEP's latest claim - that reefs occupy a smaller area of the planet -- is contradicted by its own estimates.

Far more serious, though, are the faulty connections attempting to tie "bleaching" - or whitening - of coral reefs with human-induced global warming by the burning of fossil fuels.

The idea posits that gradual human-made warming of the air either warms the water in tropical regions above levels at which coral polyps - algae that support the reefs' biosystems - can survive. Australia's Marine Institute, for example, claimed the Pacific bleaching it recorded was "caused by the combination of extremely calm conditions during the 1997-98 El Niño-La Niña events, coupled with a steadily rising baseline of sea surface temperatures in the tropics," which it then parenthetically added was "increasingly attributed to greenhouse warming."

There are problems, though, in such claims.

First, there has been no systematic increase in the severity in El Niño events over the last 100 years, according to the record shown by the U.N. Intergovernmental Panel on Climate Change. So greenhouse gas increases do not raise El Niño intensity. That means that the increase in human-made greenhouse gases has not caused coral bleaching.

The best estimate from instrumental measurements show only a very modest increase - a few tenths of a degree Celsius - in surface ocean temperature of the southern hemisphere in recent decades. But as Mark A. Cane and Michael Evans noted in an editorial in Science last November, instrumental data only scantily cover the South Pacific and go back at most a little over a century. That's a narrow window in which to measure natural changes that affect the estimate of any man-made trend.

And the temperature trends for rising ocean surface water temperatures, like those for air, are not increasing linearly. The so-called Great Pacific Climate Shift of 1976-77 has influenced them. First instrumentally observed only since 1900, that shift in the North Pacific - also called the Pacific Decadal Oscillation - recurs in patterns that can last two or three decades. Braddock K. Linsley, Gerard M. Wellington And Daniel P. Schrag were able to establish through coral samples near the island of Rarotonga a similar climate record for the South Pacific dating back 271 years. Their report, in the same edition of Science as the Cane and Evans editorial, showed South Pacific temperatures 250 years ago that were 2 degrees Celsius higher than those measured today.

Such markedly higher water temperatures prior to the onset of the industrial age, and the fact that coral communities survived, undercut the notion that human induced global warming is a real cause of concern for coral reefs. Coral blooms may be far more resilient than proponents of human-caused global warming ideas believe.

In 1995, monitoring teams in the Western Atlantic and Caribbean reported abnormally high levels of coral bleaching, with overall bleaching of reefs reaching 14% and one major reef - Lindsay Reef - found with 42% of its surface area bleached. The bleaching was blamed on rising water temperatures. By July 1996, though, according to a study by Thomas A. McGrath and Garriet W. Smith reported in Revista de Biologia Tropical, almost all the corals had recovered.

It isn't that coral reefs are indestructible. They can be and have been damaged. But coral reefs have declined and revived from short-term temperature fluctuations, and they have survived and adapted to some longer episodes as well. Suggestions that human-caused global warming have devastated these systems have not panned out.

However, real human-caused local problems that affect coral reefs demand attention.

Coral reefs suffer from overfishing, use of chemicals and explosives to bring fish to the surface, and contamination from agricultural discharge. As Jerome Jackson and 18 other scientists reported in the July 27 issue of Science, overfishing is likely the underlying cause of most coral reef degradation. Overfishing kills key sea animals that clean reef waters and seabeds, while also eliminating important predators that keep in check starfish that feed on coral polyps.

The answer to these problems won't be found by curtailing emissions of carbon dioxide, which is as necessary to life in the seas as it is on land. Rather, just the opposite of global action - local action - is vital to reef health. The United States protects the Dry Tortugas 70 miles off of Key West. Forty countries, though, accounting for a substantial area of the world's coral reefs, have no marine protected areas for their coral reef system.

To encourage such action in Latin America and the Caribbean, the House two weeks ago passed a measure sponsored by Rep. Mark Kirk of Illinois to provide debt relief credit for money spent preserving coral reefs.

This direct approach to preservation is far preferable to wasting hundreds of billions on unworkable solutions designed to lower carbon dioxide emissions.

A sharp cutback in fossil fuel use, as proponents of the Kyoto protocol desire, would have little effect on the temperature of the oceans - either now or in the future. Implementation would cut average global temperature forecast less than 0.1 degrees C by the 2050, and sea temperatures even less.

But while doing nothing to help save reefs, the Kyoto Protocol will severely cost developed nations in dramatically reduced economic growth - $300 billion a year for the United States alone. Less economic growth could quickly lead to less money going into reef protection.

Thus, those who push uneconomic and scientifically unjustified curbs on greenhouse gas emissions may end up hurting the ocean environment far more than preserving and protecting it.
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