World: A wet, warm, unhappy Christmas

This year's El Nino is the worst ever, writes Richard Lloyd Parry from Kyoto, and the knock-on effects could be heading this way
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The coral atoll called Christmas Island, deep in the eastern Pacific, has had many bad years, but few have been as devastating as 1997. It was named by Captain Cook, who landed there on Christmas Eve 1777, the first of a line of foreign visitors who came to trade, proselytise and exploit.

In the 1950s, as one of the Gilbert and Ellice Islands, it was evacuated for British and American nuclear tests, air bursts conducted over the sea a few miles offshore. When the radiation ebbed to acceptable levels, a few hundred people returned to the island, now part of the independent Republic of Kiribati, to make a simple living out of fishing, tourism and coconuts. But in the last few months, life on Christmas Island has once again been turned upside down.

A year ago it was a hot, dry desert island, fanned by brisk trade winds, and home to 14 million birds who fed off the fish on the rich coral reefs. Now it has been transformed into a monsoon climate, with 3 inches of rain every day and still, oppressive air. The roads, built by the British military to carry their nuclear bombs, are flooded. The green and pink coral, which used to attract divers from all over the world, is bleached white.

"When we left three weeks ago, 40 per cent of the reefs were dead, and I'd bet that they'll be completely dead by February," says Professor Richard Fairbanks, a climate scientist at the Lamont-Doherty Earth Observatory of New York's Columbia University. "It's gone from having the largest number of birds in the world to almost none. The sea level has risen half a metre, there are practically no fish. It's stifling hot, and the wind has gone."

The plight of a few coconut farmers in the Pacific may not appear to be a matter of global concern, but the transformation of Christmas Island has a far wider and more general significance. Geographically, and in the severity of its effects, it is at the heart of El Nino, the climatic phenomenon that has caused such a variety of chaos and suffering around the world this year.

El Ninos have been occurring for centuries, but they have been recognised by scientists only in the last 20 years, and the opportunity to study such an intense one close up has never existed before. But, even more importantly in the week of the Kyoto environment conference, Christmas Island provides a warning of the sudden and devastating changes that can be caused by small adjustments in the world's climate.

The ministers who arrive in Kyoto this weekend are attempting to reach an agreement on measures to reduce gases, principally carbon dioxide, believed to be already contributing to the warming of the globe. Switches of weather, as violent as the one which has drenched Christmas Island, have taken place all over the world and throughout history; if recent findings are anything to go on, they could happen again, much closer to home.

As global catastrophes go, El Nino sounds rather unspectacular - a warming of the surface of the eastern Pacific, on about the same latitude as Peru. As well as affecting ocean currents and the habitat of marine life, the warm sea evaporates to create clouds. The air above the sea heats up too, and winds change direction, bringing unaccustomed rain to some parts of the world while failing to deliver it to others.

On Christmas Island, it pours; in south-east Asia there is a drought, causing crop failures and forest fires which choke the cities with sickening smoke; in Australia, too, bushfires are raging out of control. But the consequences are felt throughout the world and, although it is difficult to separate the effects of El Nino from random weather variations, scientists at the Kyoto conference suggest that even the floods in Germany and last week's snow in Britain were exacerbated by El Nino.

With varying intensity, El Nino comes every three or four years, and alternates with his twin sister, La Nina, a cooling of the Pacific water which has opposite effects. Some predictions anticipate that this year's El Nino will continue into 1998. Others foresee a Nina, raising the possibility, in south-east Asia at least, of a climatological double whammy - a year of severe drought followed by a year of overwhelming floods.

This year's El Nino is the worst on record, and possibly the worst ever. Over the years, its intensity has increased along a path which looks remarkably similar to another closely watched graph - the one showing the rate of global warming. Scientists are reluctant to draw a direct connection but, according to Professor Fairbanks, "El Nino is riding on the top of a long- term trend in global warming."

Whether or not global warming causes more severe Ninos, the phenomenon is a pointed reminder of the fragility and interconnectedness of the world's climates, and the potentially massive consequences of relatively tiny events. "The best analogy is to the cogs in a watch," says Professor Fairbanks, "all different sizes, turning at different speeds, some of them directly connected, others not. People are distracted by the predictions of gentle, long-term global warming, a few degrees spread over centuries. But small perturbations in the climate can lead to large consequences, and they don't necessarily have to be gradual changes."

An alarming example of this kind of change is described by another Columbia scientist, Wallace Broecker, in the latest issue of Nature magazine. His work draws on studies of prehistoric ice extracted by drilling deep into frozen Greenland. The ice contains tiny bubbles of ancient air; by analysing it, much can be learned about the climate of the northern Atlantic millennia ago.

Several times, it turns out, and most recently 10,720 years ago, the area has undergone rapid changes, as violent in their way as those on Christmas Island. Professor Broecker attributes these to a network of interconnected ocean currents referred to as the Conveyor, which transport heat and moisture around the planet. The Conveyor is the motor behind the Gulf Stream, which flows from the Caribbean to Norway and gives Europe its mild climate. Eleven thousand years ago, this current was effectively shut down. If it happened today, temperatures would plunge. Ice would spread, agriculture would fail and Liverpool would acquire the climate of Spitzbergen, 600 miles north of the Arctic Circle. The Conveyor, as Professor Broecker describes it, "is the Achilles heel of the climate system".

It might never happen. It might start to happen any day, and all be over in the space of 10 years. Global warming might have everything, or nothing, to do with it. Whatever the accuracy of the science, it gives an additional urgency to the deliberations in Kyoto this week.

"To hold this up as an inevitable threat would be irresponsible, but to ignore this in thinking about the future would be equally naive," says Professor Fairbanks. "What we are doing here is making a risk assessment. And compared to North America, where the consequences would be less dramatic, Europeans have to think differently about the loaded gun off their shores."