Mahtab Haider reports on how shrinking Himalayan glaciers are likely to bring widespread environmental cataclysms to the countries of the Ganges-Brahmaputra delta where major rivers are fed by glacial meltwaters

Amidst the snow-capped peaks of the Annapurna Himal in the northern reaches of central Nepal nestles the high valley Manang, sprinkled with small villages that cling to steep slopes. The panorama is as breathtaking as the terrain is harsh; the terraces cradled by the craggy slopes do not yield enough high-altitude foodgrains to feed the district’s 5000 or so inhabitants. Since the time of their ancestors, the ‘Manangba’ of this region that inhabit the valley have had to make the most of brief summers, for quick-growing crops like potatoes to support their subsistence living.
   So it went, until a few years ago. Manang and its surroundings, it seems, are experiencing a slow but deliberate thaw.
   ‘Before my very eyes, this valley has become greener than I have seen it in all my 80 years,’ a local farmer told scientist Ngamindra Dahal when he visited the area in 2005. ‘Today we grow cauliflower, cabbage and tomatoes – unthinkable even a decade ago.’
   In the neighbouring district of Mustang on the other side of the Annapurna range, 53-year-old Shenjing Gurung could not remember the last time he had seen the long, chilly winters that were commonplace in his youth. ‘The people in these districts seem happy with the changes in the weather patterns,’ says Dahal with a shrug. ‘It’s easier for the aged to survive the winters, when the young people are away working down valley or as migrant labour overseas. Plus, they find that their apple harvests are improving.’
   However auspicious this turn in the weather may seem to the locals of Mustang and Manang, they herald a looming crisis for Southasia as a whole. ‘The average temperature in Nepal has been increasing by 0.09 degrees Celsius every year since the 1970s, that’s– a projected increase of roughly 9 degrees over the course of a century,’ says Dr. Madan Lal Shrestha, of the Department of Hydrology and Meteorology (DHM) in Kathmandu.
   According to one major international study, the average global temperature may rise anywhere from 1.4 to 5.8 degrees Celsius by the year 2100. At the moment, Nepal looks set to outstrip that global average by a full four degrees, and it will happen long before 2100 comes around.
   Shrestha points to a graph tacked to his wall, with a jagged line on a sharp upward incline resembling the gradient of Mt. Everest, or Sagarmatha to Nepalis. ‘That,’ he says emphatically, ‘is what the temperature chart for Nepal looks like. And make no mistake – it is global warming.’
   As political leaders of the world wrangle over the credibility of scientific data on global warming – each according to his ideological proclivity – the nay-saying scientists have fallen silent one by one. It has become clear that global warming is here, and is here to stay unless there is an emergency programme to reverse the trend in rising temperatures. The fallout of changing climate patterns are already becoming evident in forgotten corners of the developing world, while in the scientists in the United States warn that the Arctic ice has shrunk to record lows. However, one of the most unambiguous signs of global warming is, in fact, emerging out of Southasia. Warmer valleys and hotter summers are just the tip of the proverbial iceberg.
   
   Ice-albedo
   The Himalaya have the largest concentration of glaciers outside the polar caps. During the dry season, when water is in short supply, these glaciers feed eight of Asia’s greatest rivers: to the east, south and west – the Yangtze, Hwang Ho, Salween, Irrawady, Mekong, Tsangpo/Brahmaputra/Jamuna, Indus, and the many tributaries of the Ganga including the Kosi, Gandaki and Karnali that debouch from the Nepali midhills. The Marsyangdi and Kali Gandaki sub-tributaries of the Gandaki have their origins in the glaciers of Manang and Mustang. The glaciers of the Himalaya as a whole are referred to by scientists as the ‘water towers of Asia’, because they serve as storage that release water throughout the year into the rivers of Asia.
   According to a recent report by the World Wildlife Fund (WWF), 67 percent of the Himalayan glaciers are melting at a startling rate and ‘the major causal factor has been identified as climate change’. The Khumbu Glacier, from where Tenzing Norgay and Edmund Hillary began their historic ascent of Mt Everest, has retreated more than five kilometres since they climbed the mountain in 1953. The 30 km Gangotri Glacier in India, near the Badrinath pilgrimage center, has been receding over the last three decades at more than three times the rate than it had during the previous two centuries. The Rika Samba Glacier in Nepal’s Dhaulagiri region is retreating at 10 m per year. Such measurements alarm scientists, who were previously used to gauging glacial retreat in centimetres.
   And this is not just happening in Nepal’s mountains. Across the Himalaya, from Tibet in the north to the Karakoram in the west, the glaciers are melting so fast that the WWF fears that a quarter of the ice floes could disappear by 2050. ‘What’s happening with these glaciers is fairly easy to understand,’ says Arun Bhakta Sreshtha, at Nepal’s DHM. ‘The high Himalaya are warming faster than the plains because of what we call an ice-albedo feedback.’ In the climate equilibrium that has evolved over millennia, the glaciers (because of their white colour) reflect back sunlight, keeping the high-altitude peaks within a certain temperature range. As the glaciers start melting and receding, however, they reveal the darker rock underneath, which in turn absorbs more sunlight and intensifies the melting process. Meanwhile, greenhouse gases trapped in the atmosphere then reflect that heat back onto the earth’s surface, accelerating the process even further.
   ‘And this is not our unique experience,’ emphasises Arun Bhakta. ‘We are observing similar patterns of glacial melt in the Alps and the Andes.’ Recent reports suggest that the legendary snow-capped peaks of Kenya’s Mt. Kilimanjaro could be barren in less than a decade.
   ‘The melting glaciers represent a time-bomb that is ticking away even as we speak,’ cautions Pradeep Mool, a specialist on glaciers at Kathmandu’s International Centre for Integrated Mountain Development. ‘Glaciers melt to form high-altitude lakes, dammed with debris and moraine that characterises the landscape of the Himalaya. But as the water from glacial melt accumulates over the years, these dams which are structurally weak suddenly give way, resulting in what we call glacial lake outburst floods, or GLOFs.’
   GLOFS, indeed, are the most obvious results of glacial melt. In 1964, one such GLOF destroyed entire stretches of a highway in China and washed 12 timber trucks more than 70 km downstream. A GLOF at Nepal’s Dig Tsho glacier in 1985 destroyed an hydroelectric project near Namche Bazaar, as well as bridges, houses and farmlands worth. The total estimated damage was USD 4 million. ‘And it isn’t just water that crashes down into the valleys,’ says Mool, holding up a photograph from a 1991 outburst in Nepal that swept away entire villages. ‘You have rocks and other debris that rush downriver at enormous speed.’
   Since 1964, Nepal alone has witnessed 13 catastrophic GLOF events. There are over 5000 glacial lakes between Bhutan, Pakistan, India, Nepal and Tibet/China, and scientists regard at least 90 of these lakes to be potentially dangerous. ‘The real problem ,’ sighs Mool, ‘is that we don’t even know the extent of the problem, since countries such as India and Pakistan will not share the data and maps of their mountainous regions.’ As the glaciers melt and recede, there are expected to be more glacial lakes and hence more incidence of GLOFS.
   
   Southasian catastrophe
   ‘Contrary to popular perception, this isn’t Nepal’s problem or Pakistan’s problem, but a problem for the entire Subcontinent,’ urges Madan Lal Sreshtha. ‘The melt waters from these retreating glaciers mother the river systems of the Brahmaputra and the Ganga, so if these glaciers eventually disappear, the flow in the rivers will be drastically reduced and almost negligible during the non-monsoon months. Says Shrestha, ‘Glaciers accumulate snow during the Southasian monsoon and it is meltwater from these glaciers that feeds river systems that flow through India and Bangladesh during the dry season until April-May,’ he explains. ‘As the glaciers recede, not only will these rivers flood during the rainy season – with the water that is not frozen and held back by the glaciers – but in the lean seasons, there will also be less and less water in these rivers. Eventually, when the glaciers disappear, there will only be a trickle of water in these great rivers in the winter.’
   The decrease in non-monsoon flows would affect the populated plains of Southasia in a thousand different ways. Winter agriculture would suffer, recharge of underground acquifers would be affected thus reducing groundwater reserves, and the use of water for urban and industrial purpose would also be affected, as would water transport, fisheries, wetlands, and water-dependent wildlife. Overall, we are looking at long-lasting impact that that has not even begun to be studied at a time when we are just awakening to the fact of receding glaciers.
   For Bangladesh, a country that would probably fare the worst in the face of climate change because of raised sea levels, such consequences of glacial retreats in the farawaya Himalaya could be disastrous. As large swathes of Bangladesh’s coastal belt are already ravaged by cyclones, salinisation and rising sea-levels, scientists say that the decrease in volume of year-round freshwater from Himalayan glaciers could bring disease, drought, and deluge of unseen proportions.
   A model developed in part by the Indian Centre for Ecology and Hydrology reveals that glacial melt will result in ‘an increase in river discharge at the beginning causing widespread flooding in the adjacent areas.’ But after a few decades, the model warns, this situation will reverse and water levels in these rivers will start declining to permanently decreased levels. In the upper Indus, the study shows initial increases of between 14 and 90 percent in flows over the first few decades, followed by flows decreasing between 30 and 90 percent over the following century.
   For the Ganga and the Brahmaputra, the predictions of climate-change related impacts are equally apocalyptic. ‘The Brahmaputra will be worst affected because it originates in the rainshadow of the Himalaya and is largely non-rain fed, which means that it gets all its water from snowmelt,’ says Arun Bhakta Sreshtha. ‘No one can make accurate predictions about what form climate change will take in Southasia because the number of unknown variables easily outnumber the ones we have data for. What we need to do is recognise the threats we are confronted with and commission studies to understand them better.’
   
   The lumbering response
   As dismal as the prospects look, there are reasons to be hopeful. For there is an international process that is seemingly remote from the receding glaciers of the Himalaya, but which is intimately linked like these ice bodies to the issue of climate change. We are talking of the Kyoto Protocol, which sets emission reduction targets so as the try and control the runaway global warming. In February 2005, the Kyoto Protocol, became a legally binding document after it was signed by 160 states despite the attempts by the United States government to scuttle the document. Russia’s entry, prodded by the European Union, has been crucial in satisfying the Protocol’s requirement that the signatory countries account for at least 55 percent of total global emissions. ‘Russia played cat-and-mouse for a while before realising that the slowdown in their economy in the post-Soviet era meant that they had already reduced emissions significantly,’ says Dr. Saleemul Huq, of the London-based International Institute for Environment and Development. Even without US participation, the Kyoto Protocol is now being used to prod Brazil, India and China to reduce their emissions.
   ‘The tone of climate change negotiations has changed dramatically in recent years,’ says Huq. ‘The ‘south’ is no longer asking for charity when it seeks help with global warming. We consider ourselves aggrieved parties and we are seeing it as our right to compensation for damage caused by the developed world’s actions.’ According to Dr. Huq, the fallout from global warming can be likened to a precipice, slowly being approached by human civilisation. ‘It’s still a long way away, but the vessel we are in changes direction very slowly,’ he warns. ‘We are privileged to have this foresight. But in order to avoid a fall, we have to act now.’
   ‘Third world nations are at the receiving end of the damage,’ adds Madan Lal Sreshtha. ‘We can’t restrict and protect our own atmosphere. So the only option is to fall into line with a single regional or even global strategy that is scientific and serious. It’s not Nepal’s duty; it’s not Bangladesh’s duty; but the duty of all mankind.’