Glacial thawing: Greenland and Himalayas

The big thaw

Global disaster will follow if the ice cap on Greenland melts. Now scientists say it is vanishing far faster than even they expected. Geoffrey Lean reports

Independent 20 November 2005

Greenland's glaciers have begun to race towards the ocean, leading scientists to predict that the vast island's ice cap is approaching irreversible meltdown, The Independent on Sunday can reveal.
Research to be published in a few days' time shows how glaciers that have been stable for centuries have started to shrink dramatically as temperatures in the Arctic have soared with global warming. On top of this, record amounts of the ice cap's surface turned to water this summer.
The two developments - the most alarming manifestations of climate change to date - suggest that the ice cap is melting far more rapidly than scientists had thought, with immense consequences for civilisation and the planet. Its complete disappearance would raise the levels of the world's seas by 20 feet, spelling inundation for London and other coastal cities around the globe, along with much of low-lying countries such as Bangladesh.
More immediately, the vast amount of fresh water discharged into the ocean as the ice melts threatens to shut down the Gulf Stream, which protects Britain and the rest of northern Europe from a freezing climate like that of Labrador.
The revelations, which follow the announcement that the melting of sea ice in the Arctic also reached record levels this summer, come as the world's governments are about to embark on new negotiations about how to combat global warming.
This week they will meet in Montreal for the first formal talks on whether there should be a new international treaty on cutting the pollution that causes climate change after the Kyoto protocol expires in seven years' time. Writing in The Independent yesterday, Tony Blair called the meeting "crucial", adding that it "must start to shape an inclusive global solution". But little progress is expected, largely because of continued obstruction from President George Bush.
The new evidence from Greenland, to be published in the journal Geophysical Research Letters, shows a sudden decline in the giant Helheim glacier, a river of ice that grinds down from the inland ice cap to the sea through a narrow rift in the mountain range on the island's east coast.
Professor Slawek Tulaczyk, of the Department of Earth Sciences at the University of California, Santa Cruz, told the IoS that the glacier had dropped 100 feet this summer.
Over the past four years, the research adds, the front of the glacier - which has remained in the same place since records began - has retreated four and a half miles. As it has retreated and thinned, the effects have spread inland "very fast indeed", says Professor Tulaczyk. As the centre of the Greenland ice cap is only 150 miles away, the researchers fear that it, too, will soon be affected.
The research echoes disturbing studies on the opposite side of Greenland: the giant Jakobshavn glacier - at four miles wide and 1,000 feet thick the biggest on the landmass - is now moving towards the sea at a rate of 113 feet a year; the normal annual speed of a glacier is just one foot.
The studies have found that water from melted ice on the surface is percolating down through holes on the glacier until it forms a layer between it and the rock below, slightly lifting it and moving it toward the sea as if on a conveyor belt. This one glacier alone is reckoned now to be responsible for 3 per cent of the annual rise of sea levels worldwide.
"We may be very close to the threshold where the Greenland ice cap will melt irreversibly," says Tavi Murray, professor of glaciology at the University of Wales. Professor Tulaczyk adds: "The observations that we are seeing now point in that direction."
Until now, scientists believed the ice cap would take 1,000 years to melt entirely, but Ian Howat, who is working with Professor Tulaczyk, says the new developments could "easily" cut this time "in half".
There is also a more immediate danger as the melting ice threatens to disrupt the Gulf Stream, responsible for Britain's mild climate. The current, which brings us as much heat in winter as we get from the sun, is driven by very salty water sinking off Greenland. This drives a deep current of cold ocean southwards, in turn forcing the warm water north.
Research at the Woods Hole Oceanographic Institute in Massachusetts has shown, that even before the glaciers started accelerating, the water in the North Atlantic was getting fresher in what it describes as "the largest and most dramatic oceanic change ever measured in the era of modern instruments".
Even before these discoveries, scientists had shortened to evens the odds on the Gulf Stream failing this century. When it failed before, 12,700 years ago, Britain was covered in permafrost for 1,300 years.

Millions face glacier catastrophe

Global warming hits Himalayas Robin McKie, science editor

Observer November 20, 2005

Nawa Jigtar was working in the village of Ghat, in Nepal, when the sound of crashing sent him rushing out of his home. He emerged to see his herd of cattle being swept away by a wall of water.
Jigtar and his fellow villagers were able to scramble to safety. They were lucky: 'If it had come at night, none of us would have survived.'
Ghat was destroyed when a lake, high in the Himalayas, burst its banks. Swollen with glacier meltwaters, its walls of rock and ice had suddenly disintegrated. Several million cubic metres of water crashed down the mountain.
When Ghat was destroyed, in 1985, such incidents were rare - but not any more. Last week, scientists revealed that there has been a tenfold jump in such catastrophes in the past two decades, the result of global warming. Himalayan glacier lakes are filling up with more and more melted ice and 24 of them are now poised to burst their banks in Bhutan, with a similar number at risk in Nepal.
But that is just the beginning, a report in Nature said last week. Future disasters around the Himalayas will include 'floods, droughts, land erosion, biodiversity loss and changes in rainfall and the monsoon'.
The roof of the world is changing, as can be seen by Nepal's Khumbu glacier, where Hillary and Tenzing began their 1953 Everest expedition. It has retreated three miles since their ascent. Almost 95 per cent of Himalayan glaciers are also shrinking - and that kind of ice loss has profound implications, not just for Nepal and Bhutan, but for surrounding nations, including China, India and Pakistan.
Eventually, the Himalayan glaciers will shrink so much their meltwaters will dry up, say scientists. Catastrophes like Ghat will die out. At the same time, rivers fed by these melted glaciers - such as the Indus, Yellow River and Mekong - will turn to trickles. Drinking and irrigation water will disappear. Hundreds of millions of people will be affected.
'There is a short-term danger of too much water coming out the Himalayas and a greater long-term danger of there not being enough,' said Dr Phil Porter, of the University of Hertfordshire. 'Either way, it is easy to pinpoint the cause: global warming.'
According to Nature, temperatures in the region have increased by more than 1C recently and are set to rise by a further 1.2C by 2050, and by 3C by the end of the century. This heating has already caused 24 of Bhutan's glacial lakes to reach 'potentially dangerous' status, according to government officials. Nepal is similarly affected.
'A glacier lake catastrophe happened once in a decade 50 years ago,' said UK geologist John Reynolds, whose company advises Nepal. 'Five years ago, they were happening every three years. By 2010, a glacial lake catastrophe will happen every year.'
An example of the impact is provided by Luggye Tsho, in Bhutan, which burst its banks in 1994, sweeping 10 million cubic metres of water down the mountain. It struck Panukha, 50 miles away, killing 21 people.
Now a nearby lake, below the Thorthormi glacier, is in imminent danger of bursting. That could release 50 million cubic metres of water, a flood reaching to northern India 150 miles downstream.
'Mountains were once considered indomitable, unchanging and impregnable,' said Klaus Tipfer, of the United Nations Environment Programme. 'We are learning they are as vulnerable to environmental threats as oceans, grasslands and forest.'
Not only villages are under threat: Nepal has built an array of hydro-electric plants and is now selling electricity to India and other countries. But these could be destroyed in coming years, warned Reynolds. 'A similar lake burst near Machu Picchu in Peru recently destroyed an entire hydro-electric plant. The same thing is waiting to happen in Nepal.'
Even worse, when Nepal's glaciers melt, there could be no water to drive the plants. 'The region faces losing its most dependable source of fresh water,' said Mike Hambrey, of the University of Wales.
A Greenpeace report last month suggested that the region is already experiencing serious loss of vegetation. In the long term, starvation is a real threat.
'The man in the street in Britain still isn't sure about the dangers posed by global warming,' said Porter. 'But people living in the Himalayas know about it now. They are having to deal with its consequences every day.'
· Additional reporting: Amelia Gentleman and Felix Lowe