Icecaps and hurriances: the proof of climate change

Some, including influential figures on the American right, still deny the arrival of global warming. Mark Lynas has documented examples for his book 'High Tide'. Here is his compelling evidence

Thawing icecaps

No one in Fairbanks denies global warming any more. When your house is collapsing under you, there is little point in refusing to face the cause. The ground is collapsing beneath this Alaskan town. The state is among the most rapidly warming places on the planet, with temperatures rising 10 times faster than the global average. So what was once permanently frozen ground - permafrost - is thawing.

One of the worst-hit parts of town is the aptly-named Madcap Lane, which looks like a badly built Toytown. Houses pitch and lean in all directions. "I don't think anything is level here," says Viki Heiker, one of the dwindling number of residents. Her porch has fallen off, and a large crack snakes across the kitchen. Several houses in Fairbanks have been abandoned.

Other infrastructure is also affected. Roads are hastily patched as sinking ground cracks the asphalt, and the repair bill now totals $35m (£20m) a year for the state. In Alaska's interior, lakes have disappeared, draining into cracks in the thawing ground. Across Alaska, trees are toppling, caused by permafrost melt, and forests are being replaced by marshy wetland. And Alaska is not alone; large-scale permafrost melt is happening across the polar regions, from Canada to Siberia. The cause is indisputable: earth science tells us climate change should be amplified in polar regions, and this is exactly what is happening across the Arctic.

Coral bleaching

Summer is a tough time for the colourful corals of Australia's Great Barrier Reef. As sea surface temperatures rise under the baking sub-tropical sun, these tiny creatures - whose calcium carbonate skeletons form the famous reefs - begin to suffer a kind of marine heat-stroke. The coral polyps expel their companion algae and turn bone white in an increasingly-frequent event known as "bleaching".

Coral reefs are the most biologically diverse ecosystem in all the seas, holding nine million types of plants and animals, including a quarter of all known ocean fish. Yet bleaching events have devastated large sections of reef across the world. Unless the corals can recover quickly, invasive algae appear, covering the dead reefs in choking grey sheets.

In 1998, an El Niño year, and still the hottest globally on record, huge swaths of reef were killed, particularly in the Indian Ocean, which suffered 90 per cent mortality rates in some areas. The Australian marine biologist Ove Hoegh-Guldberg called it "the most serious human impact on an ecosystem ever". He estimates that overall a sixth of tropical corals were destroyed. "If we lost that proportion of the rainforests in a single year, people would be screaming," he says.

Dr Hoegh-Guldberg calculates that within 20 to 30 years, disasters on the scale of 1998 will become annual events, putting the survival of tropical reefs at risk.

Hurricanes

Coastal residents in Florida could be forgiven for keeping a nervous eye on the horizon now that this year's hurricane season has started. Records broke last year when four hurricanes in succession pounded Florida, causing $45bn (£25.5bn) worth of damage. And that was just in the Atlantic; in the Pacific, Japan was struck by a record number of typhoons, several also wreaking havoc in Taiwan, China and the Korean peninsula.

And, for the first time on record, the southern Atlantic also spawned a hurricane. Forecasters were left scratching their heads in bewilderment as the familiar swirl of clouds, complete with a well-defined eye, appeared in an ocean basin where none had been spotted before.

Hurricane Catarina struck Brazil with 90mph winds, causing up to a dozen deaths. Hurricane monitoring services may now have to be extended 2,000 miles to the south of the equator to deal with the new threat.

The stormy weather was followed by an equally stormy debate among tropical meteorologists about whether the fingerprint of global warming may be to blame. One, Chris Landsea from the Hurricane Research Division in Miami, even resigned from the intergovernmental Panel on Climate Change, accusing it of bias.

But even from a debate this politicised, a few facts do stand out. First, hurricanes are essentially heat engines, spawned only over warm ocean waters. The warmer the water, the stronger the hurricane can be. There is clear evidence that tropical Atlantic sea-surface temperatures are rising, and a broad acceptance that at least some of this must be down to human-caused global warming. So - in theory at least - each storm that forms can now be that little bit stronger. The problem comes in distinguishing this statistical signal from the huge swings of natural variability.

A hurricane is a tropical storm with winds that have reached a constant speed of 74 miles an hour or more. Hurricane winds blow in a large spiral around a relative calm centre known as the eye. The eye is generally 20 to 30 miles wide, and the storm may extend outward 400 miles.

As global warming accelerates, hurricane modellers forecast that these storms will become 10 to 20 per cent stronger as years go by, potentially breeding a greater number of monster Category 5 storms out in the Atlantic. And if one of them hits New York or Washington, even the US President will have to start taking global warming seriously.

Melting glaciers

I have a personal interest in the Andean glaciers of Peru. My father worked in the region as a geologist back in the early 1980s, and since I started writing about global warming I wanted to revisit some of the areas he had photographed more than 20 years before to see for myself how the glaciers might have changed.

My particular area of interest was the Jacabamba valley in the eastern Cordillera Blanca, a range which includes the highest glaciated peaks in the country.

At the head of the valley, my father had taken a photograph of a broad, fan-shaped glacier tumbling down from the snows above into a small lake. But when I visited two years ago, the scene was almost unrecognisable; the entire glacier had vanished, leaving just bare rock.

This is a story repeated across Peru, which has lost about a third of its glaciers in the space of just three decades. This is of vital interest to Peruvians, most of whom live in the desert strip fringing the Pacific Ocean in the west of the country, and are dependent on rivers which flow down from the Andean mountains.

These rivers run year-round because melting glaciers act as natural reservoirs, storing snowfall in the wet season and releasing the stored water into rivers all year round.

After these glaciers have disappeared - as they are projected to do within as short a time as the next two decades - then millions of people, including the population of Lima, will be left drastically short of water.

Indeed, Lima's most important icefield, Glacier Sullcon in the Cordillera Central, has already lost half of its mass, and the peaks that feed it are too low to stay frozen if global temperatures continue to rise.

The Lima water authority, Sedapal, has tried to tap new water sources by building reservoirs and drilling a water tunnel right through the Andean continental divide to a natural lake on the Amazon side of the mountains.

But the cash-strapped country cannot afford to simply engineer its way out of the crisis, and each year another large chunk of these vital glaciers simply drains away into the sea.

Desertification

Early every spring, a large part of Inner Mongolia visits the Chinese capital, Beijing. The first Beijing residents notice is an orange glow in the air, then a choking haze descends. Most of the dust in these increasingly frequent storms originates far to the north, on Inner Mongolia's once rolling grassland plains, which are turning into desert.

Official figures show more than 770square miles of China turns to desert every year. The causes are complex - over-grazing and bad agricultural management play a large role - but north China's changing climate is undeniably linked to global warming. Long-term records show a declining rainfall and temperatures have risen at twice the global average.

To the west of Inner Mongolia, in Gansu province, river systems have disappeared. The great Yellow River now fails to reach the sea on average for more than half the year. Across the region, villages are being buried by sand, as are irrigation wells, telegraph poles and roads.

There were eight dust storms in the 1960s, 14 in the 1980s and 23 in the 1990s. In the year 2000 alone, seven dust storms roared through Beijing, scouring off even road markings. The strongest storms are killers: one "black wind" in 1993 left 85 people dead.

Rising sea levels

Created from half of the Gilbert and Ellice Islands when the British colonial authorities handed over power in 1978, Tuvalu is disappearing. Global sea levels have risen by 10 to 20cm in the past 100 years, and on low-lying coral atolls such as Tuvalu the effects are already being felt. "Now is the time to start preparing, so that when people move they move with their traditions, customs and culture," said Toaripi Lauti, Tuvalu's first Prime Minister.

Early each year, during the "high tide" season, springs erupt in people's gardens, and torrents flow along the edges of roads and Tuvalu's airstrip. Lakes appear and people have to wade to their front doors. There's nowhere to run if the tide is combined with strong winds or a cyclone - no part of the atoll is more than a metre above sea level.

Plans for an evacuation of Tuvaluans to New Zealand have been tied up in red tape for years. A brief attempt to launch legal action against Australia and the US for not ratifying Kyoto never got off the ground. The idea of compensation has raised a host of problems. "How do you put a price on a whole nation being relocated?" asks Paani Laupepa, head of the environment ministry. "How do you value a culture that is being wiped out?"