Can Global Warming Make The Ganges Run Dry?
Can Global Warming Make The Ganges Run Dry?
Dr Nachiketa Das
Director, NRI-Enviro-Geo-Tech- Australia, Sydney; School of Kaya Yoga, www.kayayoga.net
(First published on September 6, 2008 on www.hotnhitnews.com.)
Global warming, now in 2008, is real, and upon us. How will global warming affect the rivers in India; will they all dry up? Can the holy Ganges, the river that has shaped and sustained Indian civilisation through the ages, who we Indians revere as the life-giving mother, run dry! Many climate experts and environmentalists, in the last ten years, have been making dire predictions of the Ganges becoming seasonal. Some doomsayers have even gone to the extent of boldly predicting the river to be ephemeral by the year 2035, which is barely a generation away! Is it really possible that the Ganges will run dry by 2035! Is this calamity an inevitability that should be accepted as fait accompli, or is there anything we, the people of India, collectively can do to save the holy Mother Ganges from extinction. This profound issue demands examination, and I propose to engage my readers in a serious debate.
Source of the Ganges
The Ganges originates from Gangotri glacier, which is one of the largest valley glaciers located in western Himalayas. 30.2 km long and 0.5 to 2.5 km wide Gangotri lies recumbent at the altitudes between 4,120 and 7,000 m above sea level. This glacier originates in a cirque, which is a natural amphitheatre like space at the base of a mountain, immediately below the locally highest Chaukhamba peak, and is fed by several tributary valley glaciers. The total area occupied by this glacier complex (in 2001) is 260 square km, which contains 40 cubic km of ice (in 1999). During a 60 year period between 1936 and 1996, Gangotri has receded by as much as 1,147 m, 850 m of which happened during a 25 year period between 1971 and 1996. In a three year period between 1996 and 1999 Gangotri retreated by 76 m. When this result is contrasted with the 2,000 m retreat over the last 200 years, the significantly accelerated rate of retreat becomes obvious. Available data show that the rate of retreat in 1971 was 19 m per year, which has now accelerated to 34 m in 2007. Having observed these rates of retreat some experts and environmentalists have speculated that due to global warming Gangotri glacier may completely disappear by 2035. If that happens, they argue that the Ganges will cease to flow during the summer months, and will drain only the monsoonal rains thus becoming seasonal. I would like to record here that while Gangotri is receding, a large number of glaciers further west are growing in size and volume! Let us investigate the issue further.
Global warming is not uniform
Global warming does not mean uniform amount of warming at each and every place on the globe. Although vast majority of the places on this earth will become hotter due to global warming, however strange it may seem, certain parts will in fact become cooler. Moreover, global warming does not mean that the earth will uniformly dry up, or for that matter there will be no rains. Although bulk of the continental landmass will become much drier, quite paradoxically again, some places will actually become wetter and receive much more rainfall. In the following section I will present discussions to convince my readers of my assertions that one: some places will become cooler, and two: some places will receive much more precipitation, due to global warming. Let me start my discussion to explain cooling, which can occur, say for instance, at a place in higher latitudes currently kept warm by the Gulf Stream.
The Gulf Stream
The Gulf Stream is a vast oceanic current that carries warm waters from the tropics to the temperate regions of northern Europe and North America. This ocean current originates in the Gulf of Mexico, flows past the east coast of the USA and Newfoundland in Canada, and then crosses the Atlantic Ocean. It then branches into two, with the northern stream moving to northern Europe. The Gulf Stream is about 80 to 150 km wide and a 1,000 m deep river of sea that transports 1.4 petawatts (1 petawatt is 1,000 million megawatts) of heat, which is equivalent to almost 100 times the current energy demand of the entire world. Around Cape Hatteras on the coast of North Carolina in the US, the Gulf Stream transports water at the rate of 80 million cubic meter per second, and is much bigger than any river system of the world; in fact the combined release of all the waters from all the rivers flowing into the Atlantic is only 0.6 million cubic meter per second.
As the Gulf Stream proceeds north, the warm waters undergo cooling due to evaporation, and the evaporative loss makes the waters heavier due to increased salinity. By the time it reaches North Atlantic, its saltier heavier and denser waters sink in the relatively less salty and less dense waters, and reverses its direction of travel and embarks on a southward journey.
The Gulf Stream has significant localised effects on the climate of the east coast of Florida and Massachusetts in the US; and the west coast of Britain, which is a good few degrees warmer than the east coast. The warming effect of the Gulf Stream is most dramatic in the western islands of Scotland, so much so that the small township of Plockton (latitude 57.33oN) that is located east of the Isle of Skye, has a mild climate that allows sub-tropical cabbage-palm-trees to grow. The local climate in Plockton in the absence of the Gulf Stream would be freezing cold as latitudinally it lies further north of Moscow (latitude 55.45oN) by almost two degrees.
Due to global warming, there is every possibility that the Gulf Stream may change course or it may lose its strength. In fact in November 2004, it completely stopped for full ten days, and there are reports saying that in the last 50 years (since 1957) its deep return flow has weakened by as much as 30%. Any change in the characteristics of the Gulf Stream, would cause significant localised cooling in Scandinavia and Britain. At a time of global warming, the western islands of Scotland will experience substantial cooling.
This very logic that global warming is not uniform is also applicable to Himalayan environment, where in certain pockets the glaciers instead of disappearing due to global warming, may start to grow due to a combination of reasons. Unlike the Scottish islands, the Himalayas, however, are not influenced by the Gulf Stream, but by an equally powerful agent, monsoon, which is discussed below.
Monsoon and its effect on Himalayan environment
Himalayan mountain system is a vast 2,400 km long arc sprawling from the west to the east. Width of this range varies from 400 km in Kashmir in the west to 150 km in Arunachal Pradesh in the east. The Himalayas consist of three parallel ranges, the northern most being the Great or High Himalayas, with an average height of 6,100 m. This is where more than a hundred mountains that exceed 7,200 m in height exist. The Great Himalayas act as a massive barrier that arrests the South West or the summer monsoon, which starts around June and continues till September, and the North East or the winter monsoon, and prevents their escape to northern Asia.
In hot summer months, intense incoming solar radiation (insolation) significantly heats up the Great Indian Desert of Thar in Rajasthan and adjoining semi-arid regions of Indian landmass causing a low pressure over north and central India. Waters of the Indian Ocean also experience similar heating that causes a large scale evaporation leading to the production of moisture laden winds. These winds flow in to fill up the vacuum created by the low pressure, and proceed north until they reach the Himalayas, which as mentioned earlier act as a huge wall, forcing the winds to rise higher. At high altitudes these moist winds cool and precipitation of rain and or snow occurs. The north-eastern part of India, where Cherrapunji is, receives abundant rainfall.
In a slight diversion from the main course of this article, I would like to record here that the name Cherrapunji, which was the anglicised version of Sohra in the native lingo, has just been reverted back to the original by the State Government of Meghalaya. Sohra receives the highest rainfall in the world of about 1,200 cm per year, and also holds two unique records. The first record is the maximum rainfall in the world of 2,299 cm in a single year (between August 1860 and July 1861); and the second, is for the maximum amount of rainfall of 930 cm in a single month in July 1861.
Now let us go back to the movement of the monsoon clouds, which then turn west and move along and over the Himalayas, in the direction of Kashmir, causing widespread rains. Intensity of the rainfall, however, decreases towards the west. The Himalayas also receive a significant amount of precipitation from the North East or the retreating monsoon of the winter months.
The South West Monsoon like the Gulf Stream is a vast natural system of transport of energy and water, and carries 1.2 petawatts (1,200 million megawatts) of heat energy. The monsoon system, both South West and North East combined, transports about 12,000 billion cubic meter of water vapour over the Indian landmass annually, a third of which precipitates as rain and snow. I will present a small calculation using some round figures to demonstrate the enormity of the volume of precipitation India receives due to the monsoon. Let me start with the annual average rainfall of India, which is about 117 cm (1.17 meter) over a landmass of 3.3 million square km. The amount of rainwater the landmass thus receives is about 3,860 billion cubic meter (1.17 m X 3.3 million km2) or say 4,000 billion cubic meter (4,000 km3).
Over the millennia these monsoonal precipitations have created the vast glacial environment in the Himalayas that now hosts 18,065 glaciers spread over a total area of 34,659 square km containing a total volume of 3,734 cubic km of ice. The vast majority of these glaciers (9,449) exist in the central Himalayas. The western Himalayas host 5,648 glaciers and the rest (2,968) occur in the eastern Himalayas. I want my readers to realise that the Himalayas have the largest concentration of glaciers outside the polar ice caps, and provide about 500 billion cubic meter (500 km3) of water annually. Unfortunately, at present, 67% of these glaciers are receding, and the retreat is being attributed exclusively to global warming by many. In the following section I demonstrate that global warming will make the monsoon system more vigorous yet erratic, which in turn will affect the general environment of the Himalayas to a significant extent.
Global warming and erratic monsoon
This year the onset of the South West Monsoon on the Indian landmass was almost a week early, and the arrival at New Delhi was two weeks ahead of schedule. The early arrival at Delhi in 2008 broke a 108 year old record. This new record may create the impression that early arrival of the South West Monsoon may become the norm. This observation may not be correct though, as in the last few years the onset of monsoon has been late too. Early or late, one fact that is obvious is that monsoon has become erratic, and global warming will make the erratic behaviour even worse. The duration of the monsoon season will also vary; it may become shorter or even longer.
As stated earlier, solar heating of sea water generates monsoon. Because of global warming, the surface water temperature of the Arabian Sea, the Bay of Bengal and the Indian Ocean that generate the South West as well as the North East Monsoons, will increase, which in turn will make monsoon more intense. I offer a simple analogy of a kettle full of water on a stove to explain the rise in intensity of the monsoon system. When the kettle is heated gently the water boils slowly and does not produce much steam. On the other hand if the kettle is heated strongly, that is the kettle receives a lot more heat, the water boils vigorously and generates copious amounts of vapour. Likewise hotter sea surface will generate more intense monsoon than a cooler sea.
A more intense monsoon system will not only raise the peak wind-speeds of the storms but also increase their frequency. In the last ten years we have already seen some very severe storms and downpours in India, Bangladesh and Myanmar. I will mention an example from each of the three above mentioned countries. The super cyclone of 29, 30 and 31 October 1999 that devastated the state of Orissa in the east coast of India had wind-speeds over 260 km per hour perhaps reaching as high as 300 km. Widespread torrential rains that accompanied this category 5 cyclone, poured anywhere between 60 to 80 cm of rain over the Mahanadi basin in the three day period. The maximum rainfall during the storm was even higher at 95 cm recorded in Bhadrak district of Orissa. I want my readers to appreciate the scale of this almost one meter rainfall in three days, which is higher than average annual rainfall of many parts, even many countries of the world.
The super cyclone caused a storm surge of about 6 m above the astronomical tide recorded at Paradip port on the 29th of October 1999, which was probably 8 m at some other coastal locations that travelled up to 20 km inland. The lethal combination of the cyclone, flooding and the storm surge killed over 10,000 people, 400,000 heads of cattle, 2 million domestic animals, and uprooted or broke 90 million trees. A vast majority of these trees had stood tall for generations, and some for centuries. Destroyed were crops over a land area of 17,110 square km, and 275,000 homes that created 1.67 million homeless. The damages by this super cyclone also known as the Paradip cyclone were simply unprecedented in the history of Orissa that made at least 5 million farmers lose their livelihood. This cyclone affected Myanmar too.
Bangladesh has seen many devastating cyclones. The latest very severe cyclonic storm that affected Bangladesh was only last year, on the 15th of November 2007 to be precise. This category 5 cyclone, Sidr attained peak wind-speeds of 260 km per hour, and caused a storm surge of over 5 m that inundated low lying coastal regions. Despite massive evacuations of the order of 2 million people, the cyclone, heavy rains and the storm surge united to cause 10,000 fatalities. Cyclone Sidr of 2007 is generally considered to be the strongest to have stormed Bangladesh since 1991 cyclone that had caused over 143,000 fatalities. Cyclone Sidr utterly destroyed the mangrove forests of entire one quarter of the vast Sunderbans that marks the very end of the Ganges-Brahmaputra delta, and is a world heritage site. The devastation was such that the forest will take at least 40 years to regenerate. This cyclone affected the Indian states of West Bengal and Orissa too.
On the 2nd of May 2008, category 4 tropical cyclone Nargis that ravaged Myanmar reached peak wind-speeds of 215 km per hour and seriously damaged the capital city Yangon. Vast areas of the low-lying Irrawady delta were inundated by a combination of torrential downpours and a 3.5 m tidal surge that caused at least 146,000 fatalities. Such severe cyclones will become even more intense and certainly much more frequent, due to global warming. These intense cyclones are evidences of the intensification of the monsoon system.
Due to the more intense monsoons, recent years have seen far heavier rainfalls practically over the entire eastern and northern parts of India, and Bangladesh. Last year serious floods played havoc with the lives and properties of hundreds of millions of people in virtually all the states of eastern India. This year, as I write this article, eastern India has received torrential rainfalls, and vast areas in the states of Orissa and Bengal have already been severely flooded rendering millions homeless. A few days ago, on the 24th of August 2008, following heavy rains in Himalayan foot-hills in eastern Nepal, the Kosi river breached its bank and opened a channel in the adjoining north Bihar, it had abandoned over 200 years ago. The initial 3 km wide breach grew at the rate of another 200 m per day. The ensuing inundation instantly affected over two million people, eventually making three million homeless. Initial reports speak of hundreds of deaths, and the fatalities are bound to rise.
Heavier rains in Rajasthan and at Tehri
I hope I have convinced my readers that monsoon will become more intense and erratic in the future due to global warming. The more vigorous monsoon will carry more water vapour, travel much faster and will generally lead to higher precipitations on the landmass of India. The monsoon clouds moreover, will penetrate deeper into the Himalayas, scale higher altitudes and probably cause significantly higher amounts of precipitation. The monsoon system might have already started penetrating deeper into the Himalayas and north-western India, evident from significantly higher rainfall in the last ten years in the north western most state of India, Rajasthan, which has been a desert state, and constitutes the last stop of the South West Monsoon before dissipation. In July 2003 the South West Monsoon caused heavy downpours in Rajasthan leading to 9 deaths. The maximum recorded rainfall in a matter of a couple of days in July 2003 was 7 cm, which is very high and unusual for the desert state. In July 2007 rainfalls were heavy too due to a vigorous South West Monsoon. The state of Rajasthan as a whole as of the 14th of August 2008 had received an average rainfall of 433 mm as against 342 mm in the same period of the previous year. 9 districts of the state recorded abnormal (60% more than average) rainfall.
Further evidence of more vigorous monsoon penetrating deeper in to the Himalayas could be gleaned from the reports of regularly higher rainfall of the past few years at the sprawling body of water of Tehri reservoir, which is barely 50 km from Gangotri glacier. I must, however, state that Tehri Dam is situated at an altitude of only 770 m above sea level where as Gangotri’s lowest point is at 4,000 m. Growth of glaciers in the western most Himalaya, also provide some very interesting evidence of vigorous monsoon, discussed below.
Growth of glaciers in the western most Himalayas
The Karakoram Range in the western Himalayas that is over 500 km further north-west of Gangotri plays host to a number of glaciers. The most prominent glacier in the Karakoram is the 74 km long Siachen, which is not only the largest Himalayan glacier but also the largest in the world outside of the polar-regions. The head of this high altitude valley glacier lies at 5,753 m above sea level at its source at Indira Col in the north, and its snout lies at an elevation of 3,620 m in the south. A glaciologist Mr VK Raina in his article published in the Journal of the Geological Society of India in 2007 has recorded that Siachen glacier ‘along its snout front has been in a rest mode’, which in plain language means that the glacier is not retreating. During my tenure with the Department of Science and Technology of the Government of India, I had the pleasure of interacting with Mr Raina, and I am quite willing to accept his observation on Siachen. Moreover, I would like to add that the neighbouring 58 km long Baltoro glacier has been reported to be advancing and so are the 40 km long Rimo I and Rimo II glaciers, which means that these glaciers are actually growing. Quite interestingly some scientists have attributed this growth to the lack of human intervention. The average winter snowfall in this region is 10.5 m, which is not insignificant.
A combination of reasons for Gangotri’s retreat
So far I have tried to convince that due to global warming the moisture content and intensity of the summer and winter monsoon should increase, and they will penetrate deeper into the Himalayas causing more precipitation. Perhaps this is happening already as evidenced from the earlier mentioned descriptions of the strong cyclones, severe floods, intense rainfall in Rajasthan and growth of glaciers in the Karakoram. If this were the case, why 67% of Himalayan glaciers, particularly Gangotri are in recession then? Some other glaciers such as Ratakona, Pindari and Milam in the vicinity of Gangotri, say within the area of a radius of a hundred km, are also in recession. They are briefly discussed below.
In Saraswati valley, north of the township of Badrinath, which is about 50 km from Gangotri, hosts Ratakona glacier very close to high altitude Mana Pass. Situated at 5,443 m above sea level, Mana Pass has been the gateway to the Indo-Tibetan trade route since time immemorial. Ratakona glacier near the pass is about to dry up, and it has disappeared entirely in the nearby Dhauli Ganga valley. Pindari and Milam glaciers that occur about a hundred km south east of Gangotri attract vast number of tourists for trekking and a range of other adventure sports, and are fast retreating too.
The recession, even disappearance of these glaciers is due to a combination of reasons, two main ones being population pressure, and massive deforestation. The holy township of Badrinath at an altitude of 3,415 m above sea level is located on the banks of the Alakananda river which joins the Bhagirathi to form the Ganges. Although Badrinath is home to only about 900 people, in 2006 season the holy town received about 600,000 pilgrims up from 90,000 in 1961. Now, in 2008 the total number of pilgrims and tourists trampling Badrinath, Kedarnath and Gangotri, is perhaps well over a million. A hundred years ago no more than a few dozen souls lived here, and barely a few hundred came on pilgrimage, and most importantly they all travelled on foot. Badrinath was then the site of the holy temple and a few nondescript little dwellings where a few sadhus lived. Now Badrinath is a sprawling township with many luxury hotels and guest houses offering spacious accommodation to these battalions of tourists and pilgrims. The construction boom at Badrinath is showing no signs of abating. Fifty years ago, there was virtually no vehicular traffic, and now the roads to Badrinath and the nearby holy towns of Kedarnath and Gangotri are choked full of flotillas of buses, trucks, jeeps and cars spewing obnoxious hot gases all the way up from their origin in the townships of Rishikesh and Haridwar at the Himalayan foothills some 300 km away. These vigorous human activities are causing significant amounts of local warming.
Each human body is a source of heat, and a million trampling the sites of Badrinath, Kedarnath and Gangotri every year give off more heat than a giant blast furnace; the heat is enough to scare the glaciers into a retreat. Had this many stampeded on to Her Majesty Queen Victoria’s Vice-Roys, the all powerful and all oppressive British Raj would have beaten a hasty retreat, half a century before 1947, and what to talk of poor Gangotri! What chance does Gangotri have to stand her ground against such a sustained onslaught by so many for so long, but to retreat! I am amazed that she is still there! And let us not blame this heat on global warming for the simple reason that when a room gets warm because of an electrical heater switched on, the warming is local and not due to global causes. I have not mentioned yet, the inimical effects of the massive deforestation on the glaciers, which is rampant even total, in these areas and the rest of the Himalayas.
Badrinath, Gangotri and all the nearby townships now stand on forest-land stripped bare. These human habitations were much smaller a century ago, and were surrounded by thick forests, which are now completely gone. The scale of deforestation here is absolute, full one hundred percent. My readers may be surprised to know the extent of deforestation in the Himalayas as a whole. The dense Himalayan forests have been so denuded in so many areas that vast patches of deserts have replaced the forests. A study published in 2001 on the deforestation of the Himalayas in Himachal Pradesh using remote sensing techniques shows the forest cover to be only 17.15 % . This result is perhaps true for the entire Himalayas, and what a shame that is for us all in India! In an attempt to further humiliate us all, I cite Japan, an advanced industrialised country where I live these days, and whose population density at 340 persons per square km is higher than that of India at 330, has a forest cover of over 70%, I repeat over seventy percent!
Forests invite rains, and as we destroy the forests, the Himalayas refuse to attract the monsoonal precipitations. Moreover, the local warming that we generate because of the million plus tourists and pilgrims in the townships of Badrinath and Gangotri, chases the monsoon clouds away. And the consequence is that at a time when monsoon is getting more intense due to global warming, certain pockets of the Himalayas like Gangotri glacier will receive lesser precipitation forcing her to retreat. This is comparable to the paradox of Plockton that I elaborated earlier in the text.
Retreating Gangotri and the need for creation of a series of glacial lakes
Glaciers scour the ground they travel, and transport the un-assorted mixture of clay, sand, gravel and boulders, known as glacial till depositing them along their flanks often forming substantial embankments known as lateral moraines. These glacial rocks and debris, when deposited at the snout where the glacier ends, form the terminal moraine. These moraines, terminal and lateral often impound glacial melt water from the retreating glaciers to create glacial lakes in the void left behind. There exist many natural glacial lakes in the Himalayas as well as in other temperate and polar regions of the world. In fact in the last few decades many glacial lakes have been forming at the termini of the glaciers in Bhutan-Himalayas.
Terminal moraines that act as natural dams for glacial lakes are inherently weak, and often, because of natural reasons again, break, causing glacial lake outbursts. The ensuing floods are known as glacial lake outburst floods, and are a common hazard in the Himalayas. Such floods are quite devastating, and have wreaked havoc in the past in China, Nepal and India. Consolidation of glacial till of the moraines, particularly the terminal moraine not only reduces the risk of glacial lake outbursts but also helps in the formation of relatively stable glacial lakes. Formation of a series of such lakes at suitable locations in Himalayan valleys where glaciers are in retreat, particularly at Gangotri, would create sources for ground water as well as surface water flow. In this context I remember Professor K S Valdiya, an eminent Himalayan geologist who I had the good fortune of interacting with during my stay with the Department of Science and Technology of the Government of India, had suggested the construction of a number of small scale gravity dams across upper reaches of the Bhagirathi to impound the melt-water from Gangotri glacier in a series of reservoirs. His decade old suggestion should be carried out to conserve the precious water. The reservoirs may quite unwittingly attract more precipitation to the region.
The concept of formation of a series of glacial lakes in the Himalayas at high altitudes need not scare the extremely powerful anti-dam lobby of India, as there already exist many such vast natural bodies of water at considerable elevations say over 4,000 m above sea level. I would name a few here, such as Dashaur lake near Rohtang pass at 4,200 m, Manimahesh lake in Chamba of Himachal Pradesh at 4,200 m, Tsomgo lake in Sikkim at 3,700 m, and the largest lake Pangong Tso at 4,600 m. Pangong Tso located at India China border is up to 8 km wide and stretches over 134 km. Moreover, the other large Himalayan lakes such as Mansarovar spread over 320 square km at an altitude of 4,600 m above sea level, and the nearby 70 square km Rakshastal at 4,750 m. I would also like to add that these lakes are often the sources of many Himalayan rivers like Mansarovar is for the Indus. Should a series of lakes be created on the upper reaches of the Bhagirathi all the way to Gangotri, they will impound enough water and replenish the ground water table enough to prevent the Ganges from becoming seasonal. It will not be out of place to record here that glacier melt water constitutes only a minor proportion (5 to 10%) of the overall runoff of the Ganges; however, the melt water is crucial as it maintains the Gangetic flow during the pre-monsoon summer months. Water impounded in the glacial lakes could well replace the glacier melt water, while making the Ganges perennial.
The legend of King Bhagirath persuading Goddess Ganges to descend from her heavenly Himalayan abode on to the plains to save the multitudes might not be an allegory; it may well contain some elements of truth. The legend could well be the historical account of a massive civil engineering project King Bhagirath undertook to break the terminal moraine of a glacial lake to channel the water to irrigate the plains parched by a prolonged drought. Many such glacial lakes formed by retreating glaciers after the end of the last ice age, 18,000 years ago, and are forming naturally even today. King Bhagirath utilised the water by breaching a terminal moraine then, and let us harness the water for rejuvenating the Ganges by consolidating the moraines now.
Need for massive afforestation of the Himalayas now
Occurrence of Himalayan glaciers at various altitudes depends on a range of conditions that include total annual precipitation, latitude, topography and aspect. Glaciers in the eastern Himalayas occur at higher altitudes compared with glaciers in the central or western Himalayas. For example, the lowest average elevation of glaciers in Arunachal Pradesh in the east is at 4,350 m above sea level, in Garhwal and Kumaun in the centre is at 4,000 m, while in Kashmir in the west it is at 3,700 m. Now due to an increase in the average Himalayan air temperature anywhere between 0.6 to 1.0 oC since the mid-1970s because of global warming, the snowline, which is the lower limit of perpetual snow, will move to a higher altitude. As the snowline migrates higher, the Himalayan tree-line, the altitude above sea level at which trees cease to grow, will rise higher too, thus making larger areas available for the growth of forests.
With the onset of global warming there is every possibility of an increase in rainfall in the Himalayas, and as nature provides a larger area for forests to grow by raising the tree-line, a massive and sincere campaign for afforestation must be undertaken now, before Himalayan forests lose their ability to regenerate. As a part of this afforestation campaign, each and every pilgrim as well as tourist, must plant a sapling of a native tree and must pay a certain amount of money towards the management of the forests. A great deal of care should be taken in afforesting the lateral moraines or the sidewalls, which traditionally supported abundant vegetation as they contained higher quantities of soil moisture. A successful regeneration of Himalayan forests will reduce local-warming, attract higher rainfall, lead to a higher retention of water in the aquifers, and will contribute to a steadier supply of the runoff in the Ganges.
Conclusion
Gangotri glacier may well disappear in the future due to a lethal combination of massive deforestation, population pressure, influx of pilgrims and tourists, and local and global warming. But if we start caring for the Ganges now on, which would involve formation of a series of glacial lakes, undertaking a massive programme of afforestation right from the foot-hills up to the elevated tree-line in the Himalayas, taking drastic measures to reduce the local warming, and reducing the pilgrim and tourist pressure, she will rejuvenate herself to a great extent, and will continue to remain perennial. But are we resolved to look after her?
I conclude this article by citing Ganga (Goddess Ganges) from the Mahabharata when she says, ‘I will stay as long you continue to address me respectfully by my proper name, and will leave should you use any abusive word to call me by’. This statement perhaps always had a deeper meaning, and meant that the Ganges will flow perennially if treated properly with respect and affection; but would cease to flow if mistreated. With the massive deforestation of her catchment, metaphorically we have disrobed her to her utter degradation. Deforestation has triggered a reduction in monsoonal precipitation, and lowered the groundwater reserves, and the two have combined to reduce the steady round the year runoff in the Ganges and her tributaries. Deforestation, moreover, has accelerated the loss of top soil and has increased the frequency and magnitude of Himalayan landslides, which have collectively supplied a vast quantum of sediments that have choked the channels of flow. And the final humiliation we have caused her is the release of vast quantities of untreated sewage, virtually along the entire length of her course. With our mistreatment we have made Mother Ganges ill. She is now showing her annoyance through the recession of Gangotri glacier. It is time we wake up, and start caring for her now on, and if we do, she will regain her health and will remain perennial, she will not leave us.
Apathy, inaction, resignation and despair are ruinous; let mass action commence to keep the Ganges perennial.
Can Global Warming Make The Ganges Run Dry?
Dr Nachiketa Das
Director, NRI-Enviro-Geo-Tech- Australia, Sydney; School of Kaya Yoga, www.kayayoga.net
(First published on September 6, 2008 on www.hotnhitnews.com.)
[Professor Dr Nachiketa Das holds a Master of Science degree in Geology (Environmental Sciences) from the School of Environmental Sciences of Jawaharlal Nehru University, New Delhi. A recipient of Commonwealth Academic Staff Scholarship tenable in the UK, Dr Das, did a Ph.D. in geochemistry from Glasgow University, Scotland. He was an officer of Harvard University where he conducted postdoctoral research on chemical evolution of atmosphere and oceans. Dr Das served the Ministry of Science and Technology of the Government of India and managed several national and international programmes in earth, atmospheric and environmental sciences. Dr Das has worked as an environmental chemist with La Trobe University, Melbourne, and as a geochemist with Commonwealth Scientific Industrial Research Organisation (CSIRO) of Australia. Dr Das was a director of a Business college in Sydney, was a consultant to the Department of Foreign Affairs and Trade, and Department of Industry Science and Tourism of the Commonwealth Government of Australia.
At present he is a director of NRI-Enviro-Geo-Tech Australia, a Special Associate Professor of the Department of Earth and Planetary Systems Science of Hiroshima University, Japan.
Professor Das is a dual citizen of India and Australia, and currently resides in Japan with his wife Mrs Shizuka Imamoto. Professor Das is a practitioner of Kaya Yoga, based on the principle of moderation, details of which are available on the website, www.kayayoga.net. Professor Das is also an award winning creative writer, and has published two books in Oriya, Kichhi Katha (a collection of short-stories), and Berlin-Berlin (a travel story). Two of his manuscripts in English, Kaya Yoga: Road to happiness, health and longevity, and A Pilgrim’s Journey, are awaiting publication. Professor Das has many publications in earth-sciences, popular science, international relations, and current affairs.
http://drnachiketadas.sulekha.com/
Dr Nachiketa Das
Director, NRI-Enviro-Geo-Tech- Australia, Sydney; School of Kaya Yoga, www.kayayoga.net
(First published on September 6, 2008 on www.hotnhitnews.com.)
Global warming, now in 2008, is real, and upon us. How will global warming affect the rivers in India; will they all dry up? Can the holy Ganges, the river that has shaped and sustained Indian civilisation through the ages, who we Indians revere as the life-giving mother, run dry! Many climate experts and environmentalists, in the last ten years, have been making dire predictions of the Ganges becoming seasonal. Some doomsayers have even gone to the extent of boldly predicting the river to be ephemeral by the year 2035, which is barely a generation away! Is it really possible that the Ganges will run dry by 2035! Is this calamity an inevitability that should be accepted as fait accompli, or is there anything we, the people of India, collectively can do to save the holy Mother Ganges from extinction. This profound issue demands examination, and I propose to engage my readers in a serious debate.
Source of the Ganges
The Ganges originates from Gangotri glacier, which is one of the largest valley glaciers located in western Himalayas. 30.2 km long and 0.5 to 2.5 km wide Gangotri lies recumbent at the altitudes between 4,120 and 7,000 m above sea level. This glacier originates in a cirque, which is a natural amphitheatre like space at the base of a mountain, immediately below the locally highest Chaukhamba peak, and is fed by several tributary valley glaciers. The total area occupied by this glacier complex (in 2001) is 260 square km, which contains 40 cubic km of ice (in 1999). During a 60 year period between 1936 and 1996, Gangotri has receded by as much as 1,147 m, 850 m of which happened during a 25 year period between 1971 and 1996. In a three year period between 1996 and 1999 Gangotri retreated by 76 m. When this result is contrasted with the 2,000 m retreat over the last 200 years, the significantly accelerated rate of retreat becomes obvious. Available data show that the rate of retreat in 1971 was 19 m per year, which has now accelerated to 34 m in 2007. Having observed these rates of retreat some experts and environmentalists have speculated that due to global warming Gangotri glacier may completely disappear by 2035. If that happens, they argue that the Ganges will cease to flow during the summer months, and will drain only the monsoonal rains thus becoming seasonal. I would like to record here that while Gangotri is receding, a large number of glaciers further west are growing in size and volume! Let us investigate the issue further.
Global warming is not uniform
Global warming does not mean uniform amount of warming at each and every place on the globe. Although vast majority of the places on this earth will become hotter due to global warming, however strange it may seem, certain parts will in fact become cooler. Moreover, global warming does not mean that the earth will uniformly dry up, or for that matter there will be no rains. Although bulk of the continental landmass will become much drier, quite paradoxically again, some places will actually become wetter and receive much more rainfall. In the following section I will present discussions to convince my readers of my assertions that one: some places will become cooler, and two: some places will receive much more precipitation, due to global warming. Let me start my discussion to explain cooling, which can occur, say for instance, at a place in higher latitudes currently kept warm by the Gulf Stream.
The Gulf Stream
The Gulf Stream is a vast oceanic current that carries warm waters from the tropics to the temperate regions of northern Europe and North America. This ocean current originates in the Gulf of Mexico, flows past the east coast of the USA and Newfoundland in Canada, and then crosses the Atlantic Ocean. It then branches into two, with the northern stream moving to northern Europe. The Gulf Stream is about 80 to 150 km wide and a 1,000 m deep river of sea that transports 1.4 petawatts (1 petawatt is 1,000 million megawatts) of heat, which is equivalent to almost 100 times the current energy demand of the entire world. Around Cape Hatteras on the coast of North Carolina in the US, the Gulf Stream transports water at the rate of 80 million cubic meter per second, and is much bigger than any river system of the world; in fact the combined release of all the waters from all the rivers flowing into the Atlantic is only 0.6 million cubic meter per second.
As the Gulf Stream proceeds north, the warm waters undergo cooling due to evaporation, and the evaporative loss makes the waters heavier due to increased salinity. By the time it reaches North Atlantic, its saltier heavier and denser waters sink in the relatively less salty and less dense waters, and reverses its direction of travel and embarks on a southward journey.
The Gulf Stream has significant localised effects on the climate of the east coast of Florida and Massachusetts in the US; and the west coast of Britain, which is a good few degrees warmer than the east coast. The warming effect of the Gulf Stream is most dramatic in the western islands of Scotland, so much so that the small township of Plockton (latitude 57.33oN) that is located east of the Isle of Skye, has a mild climate that allows sub-tropical cabbage-palm-trees to grow. The local climate in Plockton in the absence of the Gulf Stream would be freezing cold as latitudinally it lies further north of Moscow (latitude 55.45oN) by almost two degrees.
Due to global warming, there is every possibility that the Gulf Stream may change course or it may lose its strength. In fact in November 2004, it completely stopped for full ten days, and there are reports saying that in the last 50 years (since 1957) its deep return flow has weakened by as much as 30%. Any change in the characteristics of the Gulf Stream, would cause significant localised cooling in Scandinavia and Britain. At a time of global warming, the western islands of Scotland will experience substantial cooling.
This very logic that global warming is not uniform is also applicable to Himalayan environment, where in certain pockets the glaciers instead of disappearing due to global warming, may start to grow due to a combination of reasons. Unlike the Scottish islands, the Himalayas, however, are not influenced by the Gulf Stream, but by an equally powerful agent, monsoon, which is discussed below.
Monsoon and its effect on Himalayan environment
Himalayan mountain system is a vast 2,400 km long arc sprawling from the west to the east. Width of this range varies from 400 km in Kashmir in the west to 150 km in Arunachal Pradesh in the east. The Himalayas consist of three parallel ranges, the northern most being the Great or High Himalayas, with an average height of 6,100 m. This is where more than a hundred mountains that exceed 7,200 m in height exist. The Great Himalayas act as a massive barrier that arrests the South West or the summer monsoon, which starts around June and continues till September, and the North East or the winter monsoon, and prevents their escape to northern Asia.
In hot summer months, intense incoming solar radiation (insolation) significantly heats up the Great Indian Desert of Thar in Rajasthan and adjoining semi-arid regions of Indian landmass causing a low pressure over north and central India. Waters of the Indian Ocean also experience similar heating that causes a large scale evaporation leading to the production of moisture laden winds. These winds flow in to fill up the vacuum created by the low pressure, and proceed north until they reach the Himalayas, which as mentioned earlier act as a huge wall, forcing the winds to rise higher. At high altitudes these moist winds cool and precipitation of rain and or snow occurs. The north-eastern part of India, where Cherrapunji is, receives abundant rainfall.
In a slight diversion from the main course of this article, I would like to record here that the name Cherrapunji, which was the anglicised version of Sohra in the native lingo, has just been reverted back to the original by the State Government of Meghalaya. Sohra receives the highest rainfall in the world of about 1,200 cm per year, and also holds two unique records. The first record is the maximum rainfall in the world of 2,299 cm in a single year (between August 1860 and July 1861); and the second, is for the maximum amount of rainfall of 930 cm in a single month in July 1861.
Now let us go back to the movement of the monsoon clouds, which then turn west and move along and over the Himalayas, in the direction of Kashmir, causing widespread rains. Intensity of the rainfall, however, decreases towards the west. The Himalayas also receive a significant amount of precipitation from the North East or the retreating monsoon of the winter months.
The South West Monsoon like the Gulf Stream is a vast natural system of transport of energy and water, and carries 1.2 petawatts (1,200 million megawatts) of heat energy. The monsoon system, both South West and North East combined, transports about 12,000 billion cubic meter of water vapour over the Indian landmass annually, a third of which precipitates as rain and snow. I will present a small calculation using some round figures to demonstrate the enormity of the volume of precipitation India receives due to the monsoon. Let me start with the annual average rainfall of India, which is about 117 cm (1.17 meter) over a landmass of 3.3 million square km. The amount of rainwater the landmass thus receives is about 3,860 billion cubic meter (1.17 m X 3.3 million km2) or say 4,000 billion cubic meter (4,000 km3).
Over the millennia these monsoonal precipitations have created the vast glacial environment in the Himalayas that now hosts 18,065 glaciers spread over a total area of 34,659 square km containing a total volume of 3,734 cubic km of ice. The vast majority of these glaciers (9,449) exist in the central Himalayas. The western Himalayas host 5,648 glaciers and the rest (2,968) occur in the eastern Himalayas. I want my readers to realise that the Himalayas have the largest concentration of glaciers outside the polar ice caps, and provide about 500 billion cubic meter (500 km3) of water annually. Unfortunately, at present, 67% of these glaciers are receding, and the retreat is being attributed exclusively to global warming by many. In the following section I demonstrate that global warming will make the monsoon system more vigorous yet erratic, which in turn will affect the general environment of the Himalayas to a significant extent.
Global warming and erratic monsoon
This year the onset of the South West Monsoon on the Indian landmass was almost a week early, and the arrival at New Delhi was two weeks ahead of schedule. The early arrival at Delhi in 2008 broke a 108 year old record. This new record may create the impression that early arrival of the South West Monsoon may become the norm. This observation may not be correct though, as in the last few years the onset of monsoon has been late too. Early or late, one fact that is obvious is that monsoon has become erratic, and global warming will make the erratic behaviour even worse. The duration of the monsoon season will also vary; it may become shorter or even longer.
As stated earlier, solar heating of sea water generates monsoon. Because of global warming, the surface water temperature of the Arabian Sea, the Bay of Bengal and the Indian Ocean that generate the South West as well as the North East Monsoons, will increase, which in turn will make monsoon more intense. I offer a simple analogy of a kettle full of water on a stove to explain the rise in intensity of the monsoon system. When the kettle is heated gently the water boils slowly and does not produce much steam. On the other hand if the kettle is heated strongly, that is the kettle receives a lot more heat, the water boils vigorously and generates copious amounts of vapour. Likewise hotter sea surface will generate more intense monsoon than a cooler sea.
A more intense monsoon system will not only raise the peak wind-speeds of the storms but also increase their frequency. In the last ten years we have already seen some very severe storms and downpours in India, Bangladesh and Myanmar. I will mention an example from each of the three above mentioned countries. The super cyclone of 29, 30 and 31 October 1999 that devastated the state of Orissa in the east coast of India had wind-speeds over 260 km per hour perhaps reaching as high as 300 km. Widespread torrential rains that accompanied this category 5 cyclone, poured anywhere between 60 to 80 cm of rain over the Mahanadi basin in the three day period. The maximum rainfall during the storm was even higher at 95 cm recorded in Bhadrak district of Orissa. I want my readers to appreciate the scale of this almost one meter rainfall in three days, which is higher than average annual rainfall of many parts, even many countries of the world.
The super cyclone caused a storm surge of about 6 m above the astronomical tide recorded at Paradip port on the 29th of October 1999, which was probably 8 m at some other coastal locations that travelled up to 20 km inland. The lethal combination of the cyclone, flooding and the storm surge killed over 10,000 people, 400,000 heads of cattle, 2 million domestic animals, and uprooted or broke 90 million trees. A vast majority of these trees had stood tall for generations, and some for centuries. Destroyed were crops over a land area of 17,110 square km, and 275,000 homes that created 1.67 million homeless. The damages by this super cyclone also known as the Paradip cyclone were simply unprecedented in the history of Orissa that made at least 5 million farmers lose their livelihood. This cyclone affected Myanmar too.
Bangladesh has seen many devastating cyclones. The latest very severe cyclonic storm that affected Bangladesh was only last year, on the 15th of November 2007 to be precise. This category 5 cyclone, Sidr attained peak wind-speeds of 260 km per hour, and caused a storm surge of over 5 m that inundated low lying coastal regions. Despite massive evacuations of the order of 2 million people, the cyclone, heavy rains and the storm surge united to cause 10,000 fatalities. Cyclone Sidr of 2007 is generally considered to be the strongest to have stormed Bangladesh since 1991 cyclone that had caused over 143,000 fatalities. Cyclone Sidr utterly destroyed the mangrove forests of entire one quarter of the vast Sunderbans that marks the very end of the Ganges-Brahmaputra delta, and is a world heritage site. The devastation was such that the forest will take at least 40 years to regenerate. This cyclone affected the Indian states of West Bengal and Orissa too.
On the 2nd of May 2008, category 4 tropical cyclone Nargis that ravaged Myanmar reached peak wind-speeds of 215 km per hour and seriously damaged the capital city Yangon. Vast areas of the low-lying Irrawady delta were inundated by a combination of torrential downpours and a 3.5 m tidal surge that caused at least 146,000 fatalities. Such severe cyclones will become even more intense and certainly much more frequent, due to global warming. These intense cyclones are evidences of the intensification of the monsoon system.
Due to the more intense monsoons, recent years have seen far heavier rainfalls practically over the entire eastern and northern parts of India, and Bangladesh. Last year serious floods played havoc with the lives and properties of hundreds of millions of people in virtually all the states of eastern India. This year, as I write this article, eastern India has received torrential rainfalls, and vast areas in the states of Orissa and Bengal have already been severely flooded rendering millions homeless. A few days ago, on the 24th of August 2008, following heavy rains in Himalayan foot-hills in eastern Nepal, the Kosi river breached its bank and opened a channel in the adjoining north Bihar, it had abandoned over 200 years ago. The initial 3 km wide breach grew at the rate of another 200 m per day. The ensuing inundation instantly affected over two million people, eventually making three million homeless. Initial reports speak of hundreds of deaths, and the fatalities are bound to rise.
Heavier rains in Rajasthan and at Tehri
I hope I have convinced my readers that monsoon will become more intense and erratic in the future due to global warming. The more vigorous monsoon will carry more water vapour, travel much faster and will generally lead to higher precipitations on the landmass of India. The monsoon clouds moreover, will penetrate deeper into the Himalayas, scale higher altitudes and probably cause significantly higher amounts of precipitation. The monsoon system might have already started penetrating deeper into the Himalayas and north-western India, evident from significantly higher rainfall in the last ten years in the north western most state of India, Rajasthan, which has been a desert state, and constitutes the last stop of the South West Monsoon before dissipation. In July 2003 the South West Monsoon caused heavy downpours in Rajasthan leading to 9 deaths. The maximum recorded rainfall in a matter of a couple of days in July 2003 was 7 cm, which is very high and unusual for the desert state. In July 2007 rainfalls were heavy too due to a vigorous South West Monsoon. The state of Rajasthan as a whole as of the 14th of August 2008 had received an average rainfall of 433 mm as against 342 mm in the same period of the previous year. 9 districts of the state recorded abnormal (60% more than average) rainfall.
Further evidence of more vigorous monsoon penetrating deeper in to the Himalayas could be gleaned from the reports of regularly higher rainfall of the past few years at the sprawling body of water of Tehri reservoir, which is barely 50 km from Gangotri glacier. I must, however, state that Tehri Dam is situated at an altitude of only 770 m above sea level where as Gangotri’s lowest point is at 4,000 m. Growth of glaciers in the western most Himalaya, also provide some very interesting evidence of vigorous monsoon, discussed below.
Growth of glaciers in the western most Himalayas
The Karakoram Range in the western Himalayas that is over 500 km further north-west of Gangotri plays host to a number of glaciers. The most prominent glacier in the Karakoram is the 74 km long Siachen, which is not only the largest Himalayan glacier but also the largest in the world outside of the polar-regions. The head of this high altitude valley glacier lies at 5,753 m above sea level at its source at Indira Col in the north, and its snout lies at an elevation of 3,620 m in the south. A glaciologist Mr VK Raina in his article published in the Journal of the Geological Society of India in 2007 has recorded that Siachen glacier ‘along its snout front has been in a rest mode’, which in plain language means that the glacier is not retreating. During my tenure with the Department of Science and Technology of the Government of India, I had the pleasure of interacting with Mr Raina, and I am quite willing to accept his observation on Siachen. Moreover, I would like to add that the neighbouring 58 km long Baltoro glacier has been reported to be advancing and so are the 40 km long Rimo I and Rimo II glaciers, which means that these glaciers are actually growing. Quite interestingly some scientists have attributed this growth to the lack of human intervention. The average winter snowfall in this region is 10.5 m, which is not insignificant.
A combination of reasons for Gangotri’s retreat
So far I have tried to convince that due to global warming the moisture content and intensity of the summer and winter monsoon should increase, and they will penetrate deeper into the Himalayas causing more precipitation. Perhaps this is happening already as evidenced from the earlier mentioned descriptions of the strong cyclones, severe floods, intense rainfall in Rajasthan and growth of glaciers in the Karakoram. If this were the case, why 67% of Himalayan glaciers, particularly Gangotri are in recession then? Some other glaciers such as Ratakona, Pindari and Milam in the vicinity of Gangotri, say within the area of a radius of a hundred km, are also in recession. They are briefly discussed below.
In Saraswati valley, north of the township of Badrinath, which is about 50 km from Gangotri, hosts Ratakona glacier very close to high altitude Mana Pass. Situated at 5,443 m above sea level, Mana Pass has been the gateway to the Indo-Tibetan trade route since time immemorial. Ratakona glacier near the pass is about to dry up, and it has disappeared entirely in the nearby Dhauli Ganga valley. Pindari and Milam glaciers that occur about a hundred km south east of Gangotri attract vast number of tourists for trekking and a range of other adventure sports, and are fast retreating too.
The recession, even disappearance of these glaciers is due to a combination of reasons, two main ones being population pressure, and massive deforestation. The holy township of Badrinath at an altitude of 3,415 m above sea level is located on the banks of the Alakananda river which joins the Bhagirathi to form the Ganges. Although Badrinath is home to only about 900 people, in 2006 season the holy town received about 600,000 pilgrims up from 90,000 in 1961. Now, in 2008 the total number of pilgrims and tourists trampling Badrinath, Kedarnath and Gangotri, is perhaps well over a million. A hundred years ago no more than a few dozen souls lived here, and barely a few hundred came on pilgrimage, and most importantly they all travelled on foot. Badrinath was then the site of the holy temple and a few nondescript little dwellings where a few sadhus lived. Now Badrinath is a sprawling township with many luxury hotels and guest houses offering spacious accommodation to these battalions of tourists and pilgrims. The construction boom at Badrinath is showing no signs of abating. Fifty years ago, there was virtually no vehicular traffic, and now the roads to Badrinath and the nearby holy towns of Kedarnath and Gangotri are choked full of flotillas of buses, trucks, jeeps and cars spewing obnoxious hot gases all the way up from their origin in the townships of Rishikesh and Haridwar at the Himalayan foothills some 300 km away. These vigorous human activities are causing significant amounts of local warming.
Each human body is a source of heat, and a million trampling the sites of Badrinath, Kedarnath and Gangotri every year give off more heat than a giant blast furnace; the heat is enough to scare the glaciers into a retreat. Had this many stampeded on to Her Majesty Queen Victoria’s Vice-Roys, the all powerful and all oppressive British Raj would have beaten a hasty retreat, half a century before 1947, and what to talk of poor Gangotri! What chance does Gangotri have to stand her ground against such a sustained onslaught by so many for so long, but to retreat! I am amazed that she is still there! And let us not blame this heat on global warming for the simple reason that when a room gets warm because of an electrical heater switched on, the warming is local and not due to global causes. I have not mentioned yet, the inimical effects of the massive deforestation on the glaciers, which is rampant even total, in these areas and the rest of the Himalayas.
Badrinath, Gangotri and all the nearby townships now stand on forest-land stripped bare. These human habitations were much smaller a century ago, and were surrounded by thick forests, which are now completely gone. The scale of deforestation here is absolute, full one hundred percent. My readers may be surprised to know the extent of deforestation in the Himalayas as a whole. The dense Himalayan forests have been so denuded in so many areas that vast patches of deserts have replaced the forests. A study published in 2001 on the deforestation of the Himalayas in Himachal Pradesh using remote sensing techniques shows the forest cover to be only 17.15 % . This result is perhaps true for the entire Himalayas, and what a shame that is for us all in India! In an attempt to further humiliate us all, I cite Japan, an advanced industrialised country where I live these days, and whose population density at 340 persons per square km is higher than that of India at 330, has a forest cover of over 70%, I repeat over seventy percent!
Forests invite rains, and as we destroy the forests, the Himalayas refuse to attract the monsoonal precipitations. Moreover, the local warming that we generate because of the million plus tourists and pilgrims in the townships of Badrinath and Gangotri, chases the monsoon clouds away. And the consequence is that at a time when monsoon is getting more intense due to global warming, certain pockets of the Himalayas like Gangotri glacier will receive lesser precipitation forcing her to retreat. This is comparable to the paradox of Plockton that I elaborated earlier in the text.
Retreating Gangotri and the need for creation of a series of glacial lakes
Glaciers scour the ground they travel, and transport the un-assorted mixture of clay, sand, gravel and boulders, known as glacial till depositing them along their flanks often forming substantial embankments known as lateral moraines. These glacial rocks and debris, when deposited at the snout where the glacier ends, form the terminal moraine. These moraines, terminal and lateral often impound glacial melt water from the retreating glaciers to create glacial lakes in the void left behind. There exist many natural glacial lakes in the Himalayas as well as in other temperate and polar regions of the world. In fact in the last few decades many glacial lakes have been forming at the termini of the glaciers in Bhutan-Himalayas.
Terminal moraines that act as natural dams for glacial lakes are inherently weak, and often, because of natural reasons again, break, causing glacial lake outbursts. The ensuing floods are known as glacial lake outburst floods, and are a common hazard in the Himalayas. Such floods are quite devastating, and have wreaked havoc in the past in China, Nepal and India. Consolidation of glacial till of the moraines, particularly the terminal moraine not only reduces the risk of glacial lake outbursts but also helps in the formation of relatively stable glacial lakes. Formation of a series of such lakes at suitable locations in Himalayan valleys where glaciers are in retreat, particularly at Gangotri, would create sources for ground water as well as surface water flow. In this context I remember Professor K S Valdiya, an eminent Himalayan geologist who I had the good fortune of interacting with during my stay with the Department of Science and Technology of the Government of India, had suggested the construction of a number of small scale gravity dams across upper reaches of the Bhagirathi to impound the melt-water from Gangotri glacier in a series of reservoirs. His decade old suggestion should be carried out to conserve the precious water. The reservoirs may quite unwittingly attract more precipitation to the region.
The concept of formation of a series of glacial lakes in the Himalayas at high altitudes need not scare the extremely powerful anti-dam lobby of India, as there already exist many such vast natural bodies of water at considerable elevations say over 4,000 m above sea level. I would name a few here, such as Dashaur lake near Rohtang pass at 4,200 m, Manimahesh lake in Chamba of Himachal Pradesh at 4,200 m, Tsomgo lake in Sikkim at 3,700 m, and the largest lake Pangong Tso at 4,600 m. Pangong Tso located at India China border is up to 8 km wide and stretches over 134 km. Moreover, the other large Himalayan lakes such as Mansarovar spread over 320 square km at an altitude of 4,600 m above sea level, and the nearby 70 square km Rakshastal at 4,750 m. I would also like to add that these lakes are often the sources of many Himalayan rivers like Mansarovar is for the Indus. Should a series of lakes be created on the upper reaches of the Bhagirathi all the way to Gangotri, they will impound enough water and replenish the ground water table enough to prevent the Ganges from becoming seasonal. It will not be out of place to record here that glacier melt water constitutes only a minor proportion (5 to 10%) of the overall runoff of the Ganges; however, the melt water is crucial as it maintains the Gangetic flow during the pre-monsoon summer months. Water impounded in the glacial lakes could well replace the glacier melt water, while making the Ganges perennial.
The legend of King Bhagirath persuading Goddess Ganges to descend from her heavenly Himalayan abode on to the plains to save the multitudes might not be an allegory; it may well contain some elements of truth. The legend could well be the historical account of a massive civil engineering project King Bhagirath undertook to break the terminal moraine of a glacial lake to channel the water to irrigate the plains parched by a prolonged drought. Many such glacial lakes formed by retreating glaciers after the end of the last ice age, 18,000 years ago, and are forming naturally even today. King Bhagirath utilised the water by breaching a terminal moraine then, and let us harness the water for rejuvenating the Ganges by consolidating the moraines now.
Need for massive afforestation of the Himalayas now
Occurrence of Himalayan glaciers at various altitudes depends on a range of conditions that include total annual precipitation, latitude, topography and aspect. Glaciers in the eastern Himalayas occur at higher altitudes compared with glaciers in the central or western Himalayas. For example, the lowest average elevation of glaciers in Arunachal Pradesh in the east is at 4,350 m above sea level, in Garhwal and Kumaun in the centre is at 4,000 m, while in Kashmir in the west it is at 3,700 m. Now due to an increase in the average Himalayan air temperature anywhere between 0.6 to 1.0 oC since the mid-1970s because of global warming, the snowline, which is the lower limit of perpetual snow, will move to a higher altitude. As the snowline migrates higher, the Himalayan tree-line, the altitude above sea level at which trees cease to grow, will rise higher too, thus making larger areas available for the growth of forests.
With the onset of global warming there is every possibility of an increase in rainfall in the Himalayas, and as nature provides a larger area for forests to grow by raising the tree-line, a massive and sincere campaign for afforestation must be undertaken now, before Himalayan forests lose their ability to regenerate. As a part of this afforestation campaign, each and every pilgrim as well as tourist, must plant a sapling of a native tree and must pay a certain amount of money towards the management of the forests. A great deal of care should be taken in afforesting the lateral moraines or the sidewalls, which traditionally supported abundant vegetation as they contained higher quantities of soil moisture. A successful regeneration of Himalayan forests will reduce local-warming, attract higher rainfall, lead to a higher retention of water in the aquifers, and will contribute to a steadier supply of the runoff in the Ganges.
Conclusion
Gangotri glacier may well disappear in the future due to a lethal combination of massive deforestation, population pressure, influx of pilgrims and tourists, and local and global warming. But if we start caring for the Ganges now on, which would involve formation of a series of glacial lakes, undertaking a massive programme of afforestation right from the foot-hills up to the elevated tree-line in the Himalayas, taking drastic measures to reduce the local warming, and reducing the pilgrim and tourist pressure, she will rejuvenate herself to a great extent, and will continue to remain perennial. But are we resolved to look after her?
I conclude this article by citing Ganga (Goddess Ganges) from the Mahabharata when she says, ‘I will stay as long you continue to address me respectfully by my proper name, and will leave should you use any abusive word to call me by’. This statement perhaps always had a deeper meaning, and meant that the Ganges will flow perennially if treated properly with respect and affection; but would cease to flow if mistreated. With the massive deforestation of her catchment, metaphorically we have disrobed her to her utter degradation. Deforestation has triggered a reduction in monsoonal precipitation, and lowered the groundwater reserves, and the two have combined to reduce the steady round the year runoff in the Ganges and her tributaries. Deforestation, moreover, has accelerated the loss of top soil and has increased the frequency and magnitude of Himalayan landslides, which have collectively supplied a vast quantum of sediments that have choked the channels of flow. And the final humiliation we have caused her is the release of vast quantities of untreated sewage, virtually along the entire length of her course. With our mistreatment we have made Mother Ganges ill. She is now showing her annoyance through the recession of Gangotri glacier. It is time we wake up, and start caring for her now on, and if we do, she will regain her health and will remain perennial, she will not leave us.
Apathy, inaction, resignation and despair are ruinous; let mass action commence to keep the Ganges perennial.
Can Global Warming Make The Ganges Run Dry?
Dr Nachiketa Das
Director, NRI-Enviro-Geo-Tech- Australia, Sydney; School of Kaya Yoga, www.kayayoga.net
(First published on September 6, 2008 on www.hotnhitnews.com.)
[Professor Dr Nachiketa Das holds a Master of Science degree in Geology (Environmental Sciences) from the School of Environmental Sciences of Jawaharlal Nehru University, New Delhi. A recipient of Commonwealth Academic Staff Scholarship tenable in the UK, Dr Das, did a Ph.D. in geochemistry from Glasgow University, Scotland. He was an officer of Harvard University where he conducted postdoctoral research on chemical evolution of atmosphere and oceans. Dr Das served the Ministry of Science and Technology of the Government of India and managed several national and international programmes in earth, atmospheric and environmental sciences. Dr Das has worked as an environmental chemist with La Trobe University, Melbourne, and as a geochemist with Commonwealth Scientific Industrial Research Organisation (CSIRO) of Australia. Dr Das was a director of a Business college in Sydney, was a consultant to the Department of Foreign Affairs and Trade, and Department of Industry Science and Tourism of the Commonwealth Government of Australia.
At present he is a director of NRI-Enviro-Geo-Tech Australia, a Special Associate Professor of the Department of Earth and Planetary Systems Science of Hiroshima University, Japan.
Professor Das is a dual citizen of India and Australia, and currently resides in Japan with his wife Mrs Shizuka Imamoto. Professor Das is a practitioner of Kaya Yoga, based on the principle of moderation, details of which are available on the website, www.kayayoga.net. Professor Das is also an award winning creative writer, and has published two books in Oriya, Kichhi Katha (a collection of short-stories), and Berlin-Berlin (a travel story). Two of his manuscripts in English, Kaya Yoga: Road to happiness, health and longevity, and A Pilgrim’s Journey, are awaiting publication. Professor Das has many publications in earth-sciences, popular science, international relations, and current affairs.
http://drnachiketadas.sulekha.com/
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