A tsunami generated by a Southern California earthquake could deliver 50-foot waves on the region's coastline with only a few minutes' warning, according to a study focusing on what has been a largely unstudied threat.

The University of Southern California researchers who conducted the study ran computer models of earthquakes off Santa Barbara and Ventura counties and found they could trigger tsunamis powerful enough to send waves a half-mile inland in some areas.

Researcher and civil and environmental engineering professor Costas Synolakis said, "It's like the San Andreas Fault--we know one day a big earthquake will hit, but we don't know when. Personally, I think that within our lifetime we'll see a tsunami" in Southern California, he said.

If we do, he stressed, "There's absolutely no reason to panic. If you move quickly away from the beach you survive; the further you move, the better off you are," he said.

Tsunamis have hit the area before, in 1812 in Santa Barbara and in 1927 in Lompoc, according to the report, which is slated to be published in Geophysical Research Letters. It includes written accounts of eyewitnesses to the 1812 event, who told of the sea rising "like a high mountain" and said they had to move more than a mile and a half inland.

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On and off since mid-October, Britain has been pummeled by rain, whipped by winds and buffeted by storms that have caused untold millions of dollars in damage, wreaked havoc with roads and trains, and left thousands of people without habitable homes. In York, with water licking at the floor of his 13th-century residence, the archbishop of York said, "I feel like Noah in his ark."

So far this autumn, Britain--which was complaining of a drought two years ago--has endured one and a half times the average autumn's rainfall, for the wettest fall since records began 273 years ago.

The storms lashing Britain are the result of mankind's "arrogant disregard" for the delicate balance of nature, the Prince of Wales said.

He told a conference on medicine: "We have to find a way of ensuring that our remarkable and seemingly beneficial advances in technology do not just become the agents of our own destruction."

The Prince told the Millennium Festival of Medicine in London, which was organized by the British Medical Association: "As it did in the 19th century, medicine will once again have to consider the impact of pestilence and famine on human health. A new danger is the transfer of infective organisms between the animal kingdom and man, and the terrifying potential of environmental changes with their serious effects on health.

"Some recent occurrences such as the BSE [mad cow] disaster and even perhaps--dare I mention it--the present severe weather conditions in our country are, I have no doubt, the consequences of mankind's arrogant disregard of the delicate balance of nature. There is no doubt that we live in an age of unprecedented, and sometimes terrifying, technological advance where the speed of advance so often outstrips the necessary ethical considerations."

If you have ever wondered what to expect from climate change as the planet warms up, consider the roll-call of recent natural disasters.

In the United States, the West blazed in the worst fire season since, well, since anyone can remember, really. Some 350,000 hectares across 11 states burned out of control. Billions of dollars of property and priceless forests were reduced to ash.

Meanwhile, in far eastern Russia, a typhoon dumped the equivalent of three months of rain over several days. As floods swept away bridges, power lines and homes around Vladivostok and Khabarovsk, on the Chinese border, a new typhoon was forming in the Pacific Ocean. At the same time in northeastern Brazil, mudslides were crushing towns after days of torrential rain. In Canada, remote settlements were evacuated as out-of-control fires laid waste to 14,000 hectares in the north of the province of Manitoba.

And in northern Bangladesh and northeastern and northern India, monsoonal floods have cost millions their homes and dozens their lives since the start of August; the floods are bigger and faster than ever with too little vegetation and soil left in the Himalayan foothills to soak up the rain.

Looking back over the year, record floods drowned Mozambique in February. Severe drought in Mongolia is finishing off the few livestock that survived a cruel winter and the drought before that. Crops are failing in the fourth year of drought gripping East Africa. Floods from unseasonable rain in Kazakhstan in May destroyed crops and livestock and left thousands homeless. In parts of Western Australia, a 30 to 40 percent drop in average rainfall has persisted for 20 years, so long there are fears it may be permanent.

On the face of it, there is no obvious link between all these regional, disparate natural disasters. But they are the latest incidents in an ominous, emerging global pattern of more frequent, more extreme weather events.

Munich Re, the German insurance giant, keeps count: 755 natural disasters last year alone, well up from the previous record of 702 in 1998 and the long-term average of 600. In its annual report on natural hazards, the company said there is no sign of abatement: "If we compare the last 10 years of the 20th century with the 1960s, we will see that the number of great natural catastrophes increased by a factor of three [tripled]."

Given the natural variability of weather, the chief of CSIRO atmospheric research, Graeme Pearman, said it was too early yet to say definitely whether climate change was under way. But "I think maybe it is," he said.

Earth is almost one degree warmer than a century ago; scientists predict it will be two to three degrees warmer by 2100. Small variations drive big changes.

Professor Hans-Joachim Schellnhuber, the director of the Potsdam Institute for Climate Impacts Research, was in no doubt when giving evidence to the Australian Senate inquiry into climate change earlier this year.

"First of all, it has got to be stated that global warming is under way now and there is a very high probability it is enhanced by human activities," he said. "The effects will be irreversible."

sometimes every half hour. Several quakes have been so strong that national broadcaster NHK has thrown out normal programming and switched to emergency warning mode. Moreover, three volcanoes have belched large eruptions in the past four months.

Few nations are as savaged by earthquakes as Japan. The archipelago sits at a dangerous crossroads where four continent-size slabs of Earth collide. About 1,000 quakes strong enough to be felt rattle the islands every day. All that bumping and grinding has fractured the Earth's crust, resulting in 86 active volcanoes in Japan, or 10% of the world's total.

Japan's jitters heightened as a volcano on an island off Tokyo erupted in August, sending black ash into the sky and forcing the evacuation of its residents. The eruption of Mount Oyama was its biggest since 1990.

Scientists believe the volcanic activity will continue, but admit they are having trouble predicting what will happen.

To the legions of nervous Japanese seeking reassurance, that's not much consolation. Japan's capital has repeatedly been devastated by earthquakes. Quakes ravaged the city in 1703, 1782 and 1812. In 1855, 7,000 people were killed. The Great Kanto Earthquake of 1923 and the fires that it touched off killed 142,000 people and left an estimated 1.6 million people homeless. The 1995 Kobe quake killed 6,400 people, caused $90 billion in damage, seriously crimped Japanese trade and affected the global economy.

Most experts agree that, based on historical cycles, Tokyo is now overdue for another big quake. A government report released last year estimated that about 7,100 people would likely die and 500,000 homes be destroyed if a magnitude 7 quake hit the city today.

If any explorers had been hiking to the North Pole this summer, they would have had to swim the last few miles. The discovery of open water at the Pole by an icebreaker cruise ship in mid-August surprised many in the scientific community.

This finding, combined with two recent studies, provides more evidence not only that Earth's ice cover is melting, but also that it is melting at an accelerating rate. A study by Norwegian scientists projects that within 50 years the Arctic Ocean could be free of ice during the summer. Its ice sheet has been reduced by nearly half over the last four decades. The other, a study by U.S. scientists, reports that the vast Greenland ice sheet is melting. It is experiencing a net loss of water each year equal to the annual flow of the Nile River. The Antarctic is also losing ice. Huge icebergs that have broken off are threatening ships in the area.

These are not the only examples of melting. The mass of ice and snow is shrinking in the world's major mountain ranges: the Rocky Mountains in the United States, the Andes in South America, the Alps in Europe and the Himalayas in Asia.

This melting should not come as a surprise. A Swedish scientist, Svante Arrhenius, cautioned nearly a century ago that burning fossil fuels could raise atmospheric levels of carbon dioxide, creating a greenhouse effect.

As carbon dioxide concentrations have risen, so too has Earth's temperature. The warmest 23 years since record keeping began in 1866 have all occurred since 1975.

Researchers are discovering that a modest rise in temperature of only 1 or 2 degrees centigrade in mountainous regions can dramatically increase the share of precipitation falling as rain, while decreasing the share coming down as snow. The result is more flooding during the rainy season, and less melting snow to feed rivers during the dry season.

(The writer is chairman of the Worldwatch Institute, which analyzes environmental issues.)

Imagine New York toiling under the heat and humidity of Miami, and the rising seas, pushed on by storm surges, lapping at the foundations of the World Trade Center.

Picture not only major climatic upheaval--severe flooding and droughts--but also changes in the very geography of the planet, with the Everglades national park disappearing off the map and the icy wastes of Alaska giving way to prime agricultural land.

Far from the apocalyptic visions of doom merchants, these are just some of the potential scenarios which emerge from a report entitled "The Climate Change Impacts on the United States," compiled over four years by U.S. scientists under a directive issued by former president George Bush and published in draft form on the Internet in June to invite public comment.

The document suggests that if global warming continues at its current rate, average U.S. temperatures will rise by six degrees Centigrade (10 Fahrenheit) by 2100 and sea-level could rise by over two feet (60 centimeters).

Meantime, global warming may have already killed as many as 100,000 people in the past three years, according to historian David Keys in his book Catastrophe, which foresees climate change leading to mass migrations, increased disease and poverty and even war.

While the planet has always been prone to severe weather events, a pattern of increasing severity is emerging as exceptional weather conditions have left as many as 300 million people homeless since 1997.

Storms like those that battered France late last year, the worst in living memory, which took 90 lives, destroyed 270 million trees and caused more than 11 billion dollars worth of damage, will become increasingly common.

The precise effects by region are largely unpredictable. But while computer models vary in their specific predictions, they agree that the effects will be extreme.

Meantime, global warming is upon us--deserts are spreading, bringing drought and famine in sub-Saharan Africa, while the polar ice cap has thinned by nearly 50 percent in 20 years, and sea levels are rising.

Further extreme change in the coming century may ultimately endanger the survival of the human race itself.