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Sea level rise and inundation of coastal India

By: Dr Nachiketa Das
Nov-18-2008
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(Dr Nachiketa Das is Special Associate Professor, Department of Earth and Planetary Systems Science, Hiroshima University; And Director, School of Kaya Yoga, www.kayayoga.net )
 


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Global warming is making sea level rise. Sea level, however, will not rise appreciably overnight, not in months, not even in years. The rise will assume dangerous proportions only over a substantial length of time, perhaps over decades. The assertions are not designed to make you complacent my readers, but you need not panic either. The sensationalist movies and documentaries that you have been watching show the sea invading deep into eastern India, inundating the capital of West Bengal Kolkata, which as Calcutta was once the capital of British India. Moreover in these movies the ancient capital city of the state of Orissa, Cuttack that is situated at the apex of the Mahanadi delta some 70 km inland within a matter of seconds submerges under the invading sea. These movies have their own agenda, and have very successfully scared millions of viewers without ever telling much, as to how to combat the rising sea.

Sea and nature in general, have been more kind to us human beings, than we would care to admit. Nature always gives us plenty of warning before doing anything drastic, and by the same token, sea gives us a good many years to protect our landmass from her transgression. As sea level rise accelerates due to global warming, coastal India faces inundation. Although sea level rise is inevitable, the inundation of coastal India is not, and certainly it is not a fait accompli. If we decide to initiate collective action, in a scale comparable to the mass movement led by Mahatma Gandhi, we could successfully combat the rising sea, at least for a good few centuries. In this article I propose to discuss the various aspects of sea level rise, and emphasise the preventive measures that could be undertaken to save coastal India from the ravages of the rising seas.

Rate of sea level rise

Earth-scientists equipped with geological, geochemical and palaeontological (from the study of fossils) evidences have proved the existence of ice ages in earth"s history. During an ice age the temperature of the earth"s surface and atmosphere decline significantly that cause substantial accumulation of glacial ice. The most recent ice age in the earth"s history commenced around 110,000 years ago, peaked around 20,000 years ago, and ended around 10,000 years ago. While stating these ages I have deliberately provided round numbers in consideration of the fact that at different parts of the globe the last ice age peaked and ended at somewhat different times. If I may further elaborate on the regional variation, I could even state that the last ice age actually ended anywhere between 10,000 to 15,000 years ago.

Soon after the ice age reached the maximum, glaciers started melting and released vast quantities of water into the sea. Consequently sea level started rising, and has risen about 130 m in the last 18,000 years. The rate of sea level rise in time, however, has not been uniform; initially it was very fast, and then it slowed down. Most of the sea level rise, therefore, took place between 18,000 and 6,000 years before present. Let me clarify the commonly used term in earth-science "before present", which is precisely what it says, and means "ago" in common parlance.

Since 3,000 years before present till the end of the nineteenth century (1900 AD), sea level was practically constant, and did not rise much. The rate of sea level rise during this period was a mere 0.1 to 0.2 mm per year. Since 1900 AD, however, sea level has been rising more rapidly, at the rate of 1 to 2 mm per year. These numbers in millimetre do not appear large and daunting, but when accumulated say over a period of a century they do assume a menacing proportion. In the last 100 years since 1900 AD, sea level has risen by 20 cm, which is not insignificant.

In the early 1990s satellite altimetry was employed to very precisely record sea level rise. Let me explain here briefly satellite altimetry, which is an advanced piece of space technology for accurate measurement of height. Satellite altimetry very precisely measures the time taken by a radar pulse to travel from the satellite antenna to an exact point on the surface of earth and back to the satellite receiver. These data eventually provide the exact height. TOPEX/Poseidon joint satellite mission between NASA of the US, and CNES of France, launched in 1992, has measured sea level with an unprecedented accuracy. Results of TOPEX/Poseidon satellite altimetry observations show that since 1993, sea level is rising at the rate of 3.1 mm per year.

A logical question that arises now is precisely how high will sea level rise to, say by the end of the twenty-first century? This is a difficult question to answer, and many groups worldwide are already engaged in this activity, but let us make an attempt here none the less. If the current rate of sea level rise, as ascertained from satellite altimetry, remains constant at 3.1 mm per year then by 2100 AD the rise would be 310 mm or 31 cm. If this current rate of sea level rise were to remain unchanged indefinitely, there is not really much cause for concern for the near future. The current rate however, is extremely unlikely to remain constant for the next one hundred years. The calculated projection of sea level rise by 31 cm by the year 2100 AD, therefore, is far too naïve. Moreover, we know that the intensifying anthropogenic global warming would considerably accelerate the rise of sea level through two main processes: increased pace of widespread melting of glacial ice, and thermal expansion of sea water.

I suppose everyone understands rise in sea level due to melting of glacial ice but the phenomenon of sea level rise due to thermal expansion, although quite simple, may be somewhat unknown. So let me start with an explanation of thermal expansion, which is essentially a property of any matter, solid or gas or liquid, to expand when heated. Sea water, which has a huge capacity to absorb heat, is no different, and expands in volume upon heating, thus raising sea level. If sea water temperature rises by say 1oC by 2100 AD, resultant rise in sea level could reach 40 cm. A near complete melting of all the mountain glaciers of the world would make sea level rise by about 35 cm, which could well happen by 2100 AD if global warming continues unabated. So a combination of these two factors alone could raise sea level by 75 cm by 2100 AD. Let us now analyse the contributions from Greenland and Antarctica, which are still uncertain at this stage.

A just reported (September 2008) authoritative study claims that Greenland Ice Cap that currently experiences losses of 257 cubic km of ice per year due to melting, would loose 465 cubic km of ice annually by the year 2080 AD. Melt water from this body of ice raises sea level by 0.6 mm per year now, and would rise to 1.0 mm annually by 2080 AD. On the basis of this study if we arbitrarily accept contributions from Greenland Ice Cap to raise sea level by 0.6 mm per year till 2050, which then rises to 0.8 mm per year till 2080, and finally to 1.0 mm per year till 2100 AD, we get a sea level rise of 7.5 cm by 2100 AD [(0.6 mm X 50 years) + (0.8 mm X 30 years) + (1.0 mm X 20 years) = 74 mm = say 7.5 cm in 100 years].

The southern continent of Antarctica that holds the single largest volume of ice fortunately is also the slowest to melt. The current and future rate of glacial melt or the volume of ice breaking off as icebergs to enter the oceans, however, is very uncertain. A well respected study reported earlier this year in 2008, observed 85% of the entire coastline of the continent from 1992 to 2006 to assess the total glacial contribution towards the oceans. The observations were made by highly sophisticated satellite interferometric synthetic aperture radar. The results of this study reveal that the current total contribution from Antarctica that includes East and West Antarctica and Antarctic Peninsula, is about 200 cubic km per year, which is comparable to the contribution from Greenland Ice Caps, and could raise sea level by 0.5 mm per year. Although this rate of contribution from Antarctica may rise very rapidly in the future, given the uncertainty let us accept it to be similar to that of Greenland Ice Caps of 7.5 cm by 2100 AD. This statement will raise howls of protests from my colleagues, but let us accept it for the time being. The total contribution from Antarctica and Greenland to sea level rise by 2100 AD is thus 15 cm.

These simple calculations of total contributions from all the sources that I have shown in this article thus far, project a sea level rise of 90 cm by the year 2100 AD.

The uncertainty in calculating the contributions from Antarctica is essentially due to an interesting possibility of global warming causing higher precipitations in the central part of the icy continent. These much heavier snowfalls may actually result in greater accumulation of glacial ice than losses due to a combination of melting or breaking off into the oceans. The net contribution of Antarctica may thus even become negative. I would like to briefly touch upon the state of mass balance in the cryosphere, a term that embodies all the deposits of ice and snow in the world. Each year a significant volume of sea water, capable of lowering sea level, evaporates to precipitate on Antarctica and Greenland as snowfall. If no ice or ice melt water were to return to the oceans, sea level would actually fall. But that did not happen in the last few centuries as large volumes of ice entered the oceans, and a mass balance was maintained. Global warming is now all set to disturb this mass balance.

The Intergovernmental Panel on Climate Change (IPCC), which is currently chaired by a scientist from India, Dr Rajendra Kumar Pachauri, in its Third Assessment Report (TAR) of 2001 predicted that by 2100 AD, global warming would raise sea level anywhere between 9 and 88 cm. I would like to record that in 2007 the IPCC shared the Nobel Prize for Peace with Al Gore of the US. Dr Pachauri made his country proud, when on the 10th of December 2007 he accepted the prize on behalf of the IPCC.

The IPCC-TAR considered all the relevant factors of thermal expansion, mountain glaciers, glacial ice of Greenland and Antarctica, ground water and soil moisture, and permafrost to arrive at their result. But I hope my readers will bear in mind that this study was published in 2001, after which a lot more new information on melting of glacial ice have emerged. In view of this new information, the lower limit of 9 cm rise by 2100 AD appears a gross underestimation. There are many who have claimed that even the upper limit of 88 cm is an underestimate, and sea level rise could be much higher.

Given my obsession with roundness, and quite rightly so, for the earth is round, the sun is round, the moon is round, and most importantly cricket ball is round, let us accept again a round figure of 100 cm or 1 m rise of sea level by 2100 AD for our ensuing discussions, instead of 90 cm that I have demonstrated earlier in the text.

Sea level rise is not uniform

We all know that water maintains the same level. We have seen this fundamental property of water well exhibited everywhere, say in a cup of tea, in a bucketful of water, and for that matter in a bigger container like a swimming pool. How come then I claim here that the level of sea water over the globe, or for that matter sea level rise is not uniform? In order to explain this apparent intrigue, I have to remind you my readers that the earth is a fast spinning sphere, hurtling round the sun at a great speed. Let me expand a little on the speeds of this vast spinning top, which is also a space-ship.

Any place on the equatorial surface of earth, if viewed from a distance in the space, is travelling at a speed of 1,670 km per hour, which is twice as fast as a jumbo jet in full flight! I will show a simple calculation to convince you of this great speed. The equatorial radius of earth is 6,378 km which makes the equatorial circumference 40,076 km (2 X Pi X 6,378 km = 40,076 km). Any point on the equator covers this distance during the course of one full day which is about 24 hours, at a speed of 1,670 km per hour (40,076 ÷ 24 = 1670 km). The speed of revolution of earth round the sun is even faster, and let me present the calculation to convince you.

Earth"s orbit is elliptical, which requires calculating an average value for the radius for calculating the circumference. The average radius of 149.5 million km [(152 million km + 147 million km) ÷ 2] when multiplied by 2 Pi gives a circumference of 939, 336, 203.4 km, say 940 million km. Our space-ship earth covers this distance in 365 days and 6 hours travelling at a speed of 107,000 km per hour [940 million km ÷ (365.25 X 24 hours) = 107, 232 km per hour]. Our earth races round the sun at a speed at least a hundred times faster than that of a commercial airplane, whose cruising speed is no more than a 1,000 km per hour.

Having demonstrated these calculations on the speeds of rotation and revolution of the planet earth, I would like to veer off the main theme of this article, in order to lavish praises on the Father of Astronomy Arya Bhatta (476 - 550 AD), who in the fifth century AD that is over a millennium and a half ago very accurately calculated many aspects of the spinning earth. Arya Bhatta was very likely born in the erstwhile state of Kalinga, which adjoined Magadha, and stretched from the Ganges to the Godavari, and embodied the present day states of Orissa, Andhra Pradesh, Jharkhand and parts of Bihar. Equally possible it is that he was born further south in the state of Kerala. In any case, after his education he adorned the court of the king of Magadha at his capital city of Pataliputra, which now bears the name Patna. All those who enjoy slandering and disparaging the poverty-stricken inhabitants of modern Bihar, must realise that this is the state which was once Magadha that for centuries remained the heart and soul of the most prosperous and fabulously wealthy India. Let no one deride the poor of Bihar, for their desperate poverty is due to a wrong set of policies, and a complete incompetence in implementation of various developmental programmes of the state. Let us remember that each and every part of India was affluent at some point or the other in the past. Let us therefore, not deride each other on account of our relative wealth or poverty of the present day. Let us all unite, for India is one, regardless of our regionalism to eradicate this desperate poverty.

Arya Bhatta"s seminal work Aryabhatiyam was translated in to Arabic in the ninth century and subsequently it journeyed further west. Four hundred years later in the thirteenth century this treatise on astronomy was translated into Latin. The Latin version of Aryabhatiyam provided the foundation for growth of astronomy in Europe. I want my readers to appreciate that the Hindu astronomers of India built the foundation for European astronomy to stand and flourish. Arya Bhatta in a chapter of his treatise entitled Gola, which means circle or sphere, very categorically demonstrates the sphericity of earth, way before any European astronomer even had the vaguest inkling as to the size and shape of our planet. Arya Bhatta"s calculation of the equatorial circumference of earth at 39,968 km is only marginally less (by 62 km) of 40,076 km that we accept today. His calculated duration of one complete rotation of earth round its axis, which in common parlance is stated as 1 day, is absolutely correct at 23 hours 56 minutes and 4.1 seconds. Arya Bhatta also calculated the value of Pi with remarkable accuracy, and laid the foundation of many disciplines of mathematics that included trigonometry and mensuration. My reverential bow to you master, Arya Bhatta.

Coming back to the issue of non-uniformity of sea level rise, I hope I have convinced my readers that sea water is perched atop the vast space-ship called earth, travels at a tremendous speed, and is held tightly by gravitational forces. Earth"s gravity shows subtle variations across the globe depending on subterranean composition. Sea water, thus experiences subtle variations in gravitational pulls at different locations, which affect sea level. Moreover, earth"s rotation and the consequent Coriolis force, and trade winds whip the sea water to different levels at different places. For example sea level is currently 50 cm higher than the mean sea level at various Indonesian islands located between 0 and 10o S latitudes. Non-uniform changes in temperature and salinity of sea water and ocean circulations also contribute to the spatial variability in sea level.

Having convinced you of the spatial non-uniformity of sea level at any given point in time, let me assure you that at some places of the globe, sea level could even rise twice as high as the mean sea level rise.

Maximum possible rise of sea level

In order to determine the maximum height sea level could rise to, we need to discuss the total volume of ice present on our planet earth, which could completely melt. The Antarctic landmass of 13.6 million square km holds 30.1 million cubic km of ice, which constitutes about 91.5 per cent of the total ice on earth. Greenland and the Arctic contain 2.6 million cubic km of ice, which constitutes 8 percent of the total. Himalayan, Alpine and other ice caps, ice fields and valley glaciers combined, carry 0.2 million cubic km of ice, which makes up the rest 0.55 percent. The total volume of glacial ice of the world is thus 32.9 million cubic km. If all these glacial ice melts the world oceans spread over a total area of 362 million square km will rise by a maximum of 80.4 m. In order to simplify these huge numbers let me state that for every 400 cubic km of glacial ice melted, the sea level would rise by 1 mm.

The obvious question that arises now is how long would sea level take to rise to the maximum possible limit of another 80 m. We are aware that after the last glacial maximum, since 18,000 years before present, sea level rose by 80 m in about 8,000 years. The rise was thus an even one meter in a hundred years, a rate of rise identical to our projection for the twenty first century. Based on this rate we can as well say that another 8,000 years will elapse before sea level rises to the maximum. This logic may not be correct though for the simple reason that anthropogenic global warming has utterly disturbed the global climate, which in turn has provided the momentum for an accelerated pace of melting of glacial ice. If the rate of melting of glacial ice doubles, which is a real possibility, and then remains steady, which is unlikely, 80 m rise could happen in the next 4,000 years. If the rate of melting of glacial ice continues to increase after doubling, sea level may rise to its maximum potential even sooner, but certainly not before a couple of millennia.

Sea level rise and coastal inundation

Sea level rise will devastate the low-lying coastal areas of the entire world. Mainland India, endowed with a long coast line of 5,700 km will not escape the wrath of the seas. The total length of the Indian coast line is actually much longer at 7,500 km when all the island territories of Andaman and Nicobar, and Lakshadweep are taken into account. A 1 m rise in sea level say by 2100 AD will practically submerge the entire Lakshadweep group of islands and absolutely nothing can be done to save them. Let me therefore concentrate on the threats to the mainland of India, where in the absence of any preventive measures, a 1 m rise in sea level would inundate 5,763 square km of coastal land, and render 7 million people homeless.

The northern most part of the east coast of India, where the many distributaries of the Ganges and the Brahmaputra have created the vast delta, in fact the largest delta of the world, which unfortunately is barely above sea level, is the most vulnerable. Bulk of this Ganges-Brahmaputra deltaic system is situated in Bangladesh, and the rest in the Indian state of West-Bengal, which thus is the most vulnerable state in India. The riverine Orissa that lies immediately to the south of West-Bengal is also very vulnerable, for the deltas it hosts, created by the Subarnarekha, the Budhabalanga, the Baitarani, the Brahmani, the Mahanadi and her distributaries, and the Rusikulya, in a traverse from the north to the south. Further south along the east coast appear the huge deltas laid by the Godavari and Krishna river systems, and the Penner in the state of Andhra Pradesh, followed by the Cauvery delta of the southern most state of Tamil Nadu. All these deltas being low-lying are vulnerable to inundation when sea level rises. Although the west coast of India does not host large deltas, is not immune from the threats of sea level rise. Kutch region of Gujarat, greater Bombay and southern parts of Kerala will be utterly devastated by the rising seas.

A 1 m rise of sea level will inundate 1,810 square km of land in Gujarat, 1,220 square km in West-Bengal, 670 square km in Tamil Nadu, 550 square km in Andhra Pradesh, 480 square km in Orissa, 410 square km in Maharashtra, 290 square km in Karnataka, 160 square km in Goa, and 120 square km in Kerala. I hope the enormity of the problem India faces due to sea level rise now dawns on you, my readers.

Coastal inundation after the last ice age

Many people in India, and for that matter in the advanced industrialised countries of the world, are still not convinced of the problem of sea level rise. In order to convince you, I record here that sea level rise by 130 m since the last glacial maximum 18,000 years ago, has inundated over 250,000 square km of land in the west coast of India. On this submerged land, which was once coastal Gujarat, flourished the grand city of Dwaraka that Sri Krishna built all those millennia ago. Thanks to the many underwater surveys and excavations most diligently carried out by the archaeologists of the venerable Archaeological Survey of India (ASI), and by the marine scientists of the National Institute of Oceanography (NIO), we have now discovered two extensive submerged ruins, one off the present-day city of Dwaraka at depths of 15 to 20 m below sea level. The other one, ruins of a vast metropolis that stretches for 9 km on the seabed of the Gulf of Khambhat (formerly known as the Gulf of Cambay), lies at a depth of 25 to 40 m. These second ruins now termed the Gulf of Khambhat Cultural Complex (GKCC), 40 km off the coast of Surat in Gujarat were a monumental discovery in December 2000. Either of these ruins could be Sri Krishna"s Dwaraka.

Although there have been subsidence as well as uplift of land in this submerged continental shelf off the coast of Gujarat, it is not unreasonable to attribute the depths of the two underwater ruins essentially to sea level rise. Now let us make an attempt to ascertain the age of submergence of Dwaraka based on information from global sea level rise. A 15 m rise of sea level took place over a period of 8,000 years, and 25 to 40 m rise took place over a period of 10,000 years. On the basis of these ages, I feel confident to state that Sri Krishna"s Dwaraka was inundated at least 8,000 years ago. This information also implies that the fratricidal war between the Kauravas and the Pandavas, description of which constitutes the subject matter of the greatest epic Mahabharata took place at least 8,000 years ago. This age contradicts, and quite rightly so, the speculative age for the Mahabharata at 1,000 BC, which was proposed by the nineteenth century Europeans, essentially British, whose prime interest was to distort the history of India to perpetuate English supremacy.

And to their utter shame and disgrace, countless historians of India, even in this twenty-first century, six decades after the independence of India, keep parroting the English version of Indian history. I appeal to you the historians of India, to take cognisance of the vast amounts of archaeological and geological evidences pouring in, in the last decade or so, and to rectify the horrendous distortions of Indian history to restore the dignity it so richly deserves. In stead of remaining arm-chair bound, it is time for you lot to don SCUBA (Self-Contained-Under-Water-Breathing-Apparatus) gear to explore and excavate the Indian continental shelf off the coast of Gujarat, Orissa, Andhra Pradesh and Tamil Nadu to gather more evidence to reconstruct the rich past of India. As a student of earth history, geology and environmental science I have climbed mountains and dived in the seas, and earned my right to advise you the arm-chair historians of India to wake up from your slumber. And most importantly let the ages you determine of the various historical events like the Mahabharata, inundation of Sri Krishna"s Dwaraka, antiquity of Ramayana, the Vedas, and Jagannath Puri, not get stunted by the writings of British historians, particularly by their Aryan invasion of India hypothesis which at 1,200 BC tries desperately to limit the much older Indian civilisation. I would also like to record here that the Mahabharata was never a myth, it is history albeit richly embellished, and most eloquently narrated by the greatest writer in human history, Vyaasadev.

Ages of the pieces of pottery recovered from the Gulf of Khambhat Cultural Complex (GKCC) during underwater explorations in 2003 and 2004 by the scientists of National Institute of Oceanography (NIO), determined in laboratories in Oxford in Britain and in Hanover in Germany, are 31,000 years. This discovery has most comprehensively discarded the utterly incorrect premise that the Indian civilisation started because of Aryan invasion around 1,200 BC. India was the cradle of urban civilisation, which started much earlier at least 31,000 years ago, when vast cities flourished in the deltaic plains of the Saraswati River, so eloquently praised and admired in the Vedic literature. During that time, last ice age reigned, sea level was at least 130 m below the present level, and much of the Indian landmass was covered by glacial ice. As the ice age came to an end, sea level rose and many of those vast cities like the GKCC on the west as well as on the east coasts of India were submerged. Glaciers also retreated, creating space for the construction of new urban centres at higher altitudes and latitudes of the landmass of India. In all probability, it is the urbanised Indians who moved beyond the geographic confines of the subcontinent to create urban settlements elsewhere.

Having provided an example of a massive submergence from the west coast, I present here another small and interesting observation from the east coast of India. All through the history of Orissa, the site of the famous Jagannath temple at coastal Puri has been referred to as a mountain, often described as Neelakandara or Neelachala or even Mahameru. Since neela is blue, and the words kandara, aachala and meru mean mountain, etymologically Neelakandara and Neelachala mean Blue Mountain, and Mahameru means Great Mountain. In the twenty-first century, the site of the Jagannath temple is barely at 10 to 15 m above sea level, which hardly qualifies as a mountain. I want my readers to appreciate that these very words Neelachal, Neelakandara and Mahameru connote history, and when I take you back in time to 18,000 years before present when seas were 130 m below the present level, the site of Jagannath temple suddenly assumes an impressive height of say 150 m. The present Jagannath temple which is barely a thousand years old did not exist then, but the precursor or the previous incarnation of Jagannath, Neela Madhava or the Blue Vishnu, who is much older than Sri Krishna, adorned that Blue Mountain. The rising seas have reduced that imposing Blue Mountain to a mere mound today.

During the last ice age, I might as well record here that the snow line was much lower. The Himalayan range was of course all covered with glaciers but mountains in the deep south of Tamil Nadu and Kerala also had ice caps. Snowline in locations at 10o latitude existed at 1,000 m above sea level, which means that the Nilgiris that have an altitude of around 2,500 m today, hosted glaciers then. At 20o latitude snowline was down to 600 m, which means that practically all the higher mountains of the Aravalli, the Vindhya, the Western Ghat and the Eastern Ghat ranges were home to glaciers. The Mahendra Giri of Orissa at 1,200 m and the adjoining hills of the Eastern Ghats in Andhra Pradesh hosted a massive complex of glaciers. Should my fellow earth-scientists start careful research for glacial geomorphological features, and glacial debris in these mountains, they may find some. Sediment cores from suitable lake beds in these mountainous areas would produce pollens of temperate flora that flourished during the last ice age. I would also like to add that practically all the rivers of the peninsular India were snow fed and drained glacial melt waters in the past.

Losses due to sea level rise

The rising seas now threaten to inundate the deltaic plains of the east coast of India, which are well and truly the bread baskets of the country, for they provide prime agricultural land. Agricultural productivity of these fertile tracts is often double the average productivity of the country. On the west coast, the rising seas threaten the vast commercial and industrial complexes. As sea level rises, coastal erosion will increase very substantially along the entire shoreline, ground-water quality will be compromised, and storm surges will become much more frequent as well as intense, destroying infrastructure.

In an earlier article, Can Global Warming Make The Ganges Run Dry? (http://drnachiketadas.sulekha.com, www.blogs.siliconindia.com/DrNachiketaDas) also published under the caption, River Ganges Faces The Wrath Of Global Warming, (www.hotnhitnews.com) I discussed in great detail that as sea level rises due to global warming monsoon will become far more intense and erratic, which will not only make storms more numerous but also raise their peak wind-speeds. We have already seen some very severe storms in the last ten years, perhaps the strongest of which remains the Paradip super-cyclone of October 1999. This category 5 cyclone lashed coastal Orissa with wind-speeds over 260 km per hour perhaps reaching a maximum of 300 km. This 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. Now let me assure you that we will witness stronger cyclones and even stronger storm surges in the future due to global warming, which will make the tides penetrate even deeper inland. And the devastations will be far more severe.

The economic aspect of global warming and sea level rise will probably emerge as a new interdisciplinary subject in the near future. In stead of attempting any calculations to put a price on coastal inundation due to sea level rise, I would merely make a generalised statement that the economic losses will run in to thousands of trillions of rupees.

Achyutananda"s prophecy on sea level rise

My forebear Achyutananda Das, the fifteenth century Oriya poet, philosopher and yogi, was a great seer. He was born in a village by the name Nemala, where the distributaries of the mighty Mahanadi River, the Luna and the Chitrotpala diverged. After his birth and early childhood in Nemala, which is 30 km or so from the ancient capital city of Cuttack, Achyutananda moved to Puri where his father Dinabandhu Khuntia was in the employ of the Jagannath temple. His grand father Gopinath Mohanty had also served the holy temple as a scribe. Through his forefathers Achyutananda was attached to Jagannath, and subsequently became a devotee of the Lord, worshipping Him as the Buddha. His austere adherence to yoga, meditation and to the rituals of Buddhist tantra, endowed Achyutananda with great spiritual abilities that made him a prolific author and an incomparable seer. My grandfather, Alekh Prasad Das, in his award winning autobiography, Jibanara Daka, has recorded Achyutananda"s spiritual powers, and has claimed my family"s descent from the seer.

The many books of Achyutananda, which could loosely be termed as a collection of Books of Prophecies, contain bold predictions of the sea inundating coastal Orissa. His prophecies describe in detail a week of incessant rains and the events leading up to the marine transgression and subsequent inundation of the sprawling stone stair case, comprising twenty-two steps, of the Jagannath temple of Puri. On the 3rd of September 2008, respected Oriya daily the Dharitri in its editorial cited Achyutananda"s prophecies of fish swimming on the Twenty-two Steps. Achyutananda further elaborates the marine transgression with graphic details of sea-water submerging the pedestal in the sanctum sanctorum of the temple, presently adorned by the deities.

My grandfather used to describe me these prophecies, when I was only a child studying under his tutelage in the village primary school. I failed to comprehend the concept of marine transgression, and did not quite fathom the deluge then. Consequently I never really understood the prophecies. And as luck would have it, I moved to Puri for my high school education, and saw the Jagannath temple and the sea. I distinctly remember a classmate of mine who hailed from the township of Puri telling me of the prophecies again, which by the way are a part of the established folklore of the holy temple town since their issuance in the early part of the sixteenth century. My friend had quoted that the 65 m tall Jagannath temple will be submerged completely. I had dismissed his words out of hand; I never paid much attention to what he had said. Whenever I frolicked on the vast sandy beaches and on the premises of the Jagannath temple, I was most reluctant to accept that this revered temple could ever be so overwhelmed. I dismissed the prophecies as figments of imagination or superstition at best.

Only after I embarked upon my studies in earth sciences, which have now taken me to many parts of this magnificent planet we call home, and lodged me in quite a few venerable universities and institutions of the world, I learnt that marine transgression and regression are geological facts. Moreover they have occurred regularly in earth"s history. I realised that the sea level could indeed rise to inundate the Twenty-two Steps of the Jagannath temple, which are barely 10 to 15 m above sea level. In fact the deluge could entirely submerge the Jagannath temple that stands just about 80 m above sea level, as prophesied. As explained earlier in the text 80 m is in fact the upper limit of sea level rise should all the glacial ice of the world were to melt away. Call it a coincidence or a remarkably accurate prophecy by a remarkably accurate seer, the choice is yours. It is about time that the world knows of this very great seer.

On the 15th of September 2008, only a month ago, a mere 100 km per hour storm, whipped off a 6 m storm surge that inundated 20,000 hectares of agricultural land, tens of villages, and severely affected thousands of families of coastal Orissa. A strong cyclone with wind speeds of 300 km per hour could easily create a storm surge of 10 m high. Should a surge of this magnitude hit the coastal township of Puri on a full-moon day at high tide during the monsoon, sea-water will indeed inundate Puri and the Twenty-two Steps of the Jagannath temple. This could happen any time now, say by the middle of this twenty-first century, even before a substantial rise in sea level.

So confident was Achyutananda of his prophecies that in one of his writings he says:
"Parbata sikhare phutiba kain,
Achyutara katha taliba nahin";
which when translated into English would read:
Water lilies will bloom atop the mountains blue,
Mark Achyuta"s words, for they will come true. (Translation ND).

However, astounding this prediction may appear, it is not all that far fetched. Let me explain, very briefly, how this could eventuate. The very site of the Jagannath temple, Neelachala, which as explained earlier in the text was once an impressive mountain, is barely above sea level thanks to the rising sea. As the sea rises even higher, places along the coast which were once hill tops during the last ice age, will be water logged ponds where lilies will bloom.

Achyutananda"s confident prophecies scare me, and give me the feeling that the people of the east coast of India perhaps will do nothing to combat the rising sea, which will transgress and inundate this rich and fertile stretch of land. I feel deeply hurt when I visualise the inundation of Puri where I completed my high school education, and spent some very happy teen-age years frolicking on those beautiful sandy beaches. Some of my dearest friends whom I have loved and admired hail from this holy and enchanting township. Visualisation of the inundation of their lovely houses, which have stood as indelible land marks in my life"s journey, pains me immensely. Let us unite and initiate preventive action to combat the rising sea, for inaction would make Achyutananda"s prophecies come true much sooner than we wish.

Measures to combat the rising seas

Now the big question arises, is there anything at all that could be done to combat the rising seas; particularly at a time when global warming continues unabated making sea level rise inevitable. Let me respond that although sea level rise is inevitable, coastal inundation at least for the next few centuries, is avoidable provided we take preventive action. Let us discuss the preventive action we could take.

Bengal has devised its own unique set of techniques to deal with problems of any magnitude. Considering the current state of affairs in West-Bengal, I would assume that the threat of sea level rise would be confronted by the battalions of comrades led by their formidable leaders, who would assemble on the beaches and raise their voices in unison to shout:
Sea level rise, nahin chalega nahin chalega;
Bay of Bengal! Wapas jao wapas jao.
Although this kind of slogan shouting has been very successful in driving away industrialisation, employment, growth, prosperity and the Tatas from West-Bengal, I do not foresee this technique succeeding in forcing the Bay of Bengal to retreat. For the benefit of my non-Indian friends I provide a glossary of the revolutionary terminology just used: nahin chalega - will not do, wapas jao - go back.

I am at pains to record that West-Bengal in the first decade of the twenty-first century is a mere shadow of the Bengal of a century earlier. In those heydays Bengal produced a great many luminaries, who led social reforms, educational reforms, and industrialisation in India. The leaders, intellectuals and nationalists of Bengal led the Indian freedom movement through their phenomenal organisational skills, inspirational speeches, salutation of "Jai Hind" (introduced by Dr Champakaraman Pillai and immortalised by Netaji Subhas Chandra Bose as the battle-cry of Indian National Army), and the passionate songs of "Bande Mataram" (composed by Bankim Chandra Chattopadhyay), "Amar Sonar Bangla" (written by Rabindra Nath Tagore), "Kadam kadam badhai ja" (marching song of Indian National Army, composed by Ram Singh) that reverberated across the length and the breadth of India to unite a nation. So vociferous were the Bengalis in their protests against the colonial rule that the British Vice-Roy Curzon applied the time-tested nefarious British tactic of "divide and rule" and partitioned their state on the 16th of October 1905 along religious lines, in order to subjugate them. The division of the state into East and West-Bengal was designed to pit the Hindus against the Muslims who spoke the same language of independence of India then. I would like my readers to remember that it is the British Raj that had sown the seeds of partition of India with the division of Bengal, and not Mohammad Ali Jinah who as a brilliant 29 year old lawyer in 1905 was hired by the Hindu nationalist freedom-fighter Bal Gangadhar Tilak as the defence counsel for his sedition trial. Jinah was a champion of Hindu-Muslim unity then, and rose to prominence in 1916 as the President of the Muslim League, which was formed in 1906, a year after the partition of Bengal. Having praised you so much my Bengali friends, I would like to mention that it is time now for West-Bengal, the state which will suffer most in the east due to sea level rise, to provide leadership on the east coast to combat the rising sea. I appeal to you my brothers and sisters of Bengal to unite; let us put aside the divisive politics and embark upon a collective mass action to combat the menace of the rising sea.

And let Gujarat, the state that is going to suffer the most in the west, take up the leadership of the west coast. My brothers and sisters from Gujarat, you produced the greatest leader of the twentieth century, Mahatma Gandhi, and you certainly can provide the leadership now.

The very first step in the preventive action to combat the rising seas to save our coasts is creation of awareness among the masses through a comprehensive education programme to ensure their active participation. In the second stage we have to embark upon a truly epic programme of coastal-engineering works in a scale unprecedented, and perhaps at least ten times bigger than the endeavours of the Dutch in Holland in the last 50 years.

The Netherlands is up to 6 m below sea level

The Netherlands, informally known as Holland, along with Belgium when ruled by Spain and Austria, before 1581 AD, were known as the Low Countries. The very word "nether", means lower or under. Consequently the Netherlands means the country of low-lying lands. The total geographic area of Holland is about 41,526 square km, half of which lies below sea level and was covered by the sea, lagoons and swamps. In the last eight hundred years, the native Dutch people have reclaimed bulk of this land by pumping sea-water back into the sea. The Dutch are so proud of their land reclamation efforts that they have a saying, which in English would read, "God created the world, but the Dutch created Holland". The reclaimed areas of the country are called polders, which now constitute the heart of the Netherlands. Amsterdam, the capital and the largest city of the country, is built on a polder, and lies almost 6 m below sea level.

The Netherlands is located on the low-lying deltaic plains of the Rhine River system, and in 1953 experienced a massive flooding disaster that killed nearly 2,000 people and destroyed 47,000 buildings. Following the inundation, a vast construction effort known as the Delta Works was undertaken in 1958, which continued right up to 2002, to end the threat from the sea. The project involved construction of 3,000 km of outer sea-dykes or ramparts, and 10,000 km of inner canal- and river-dykes. The outer sea-dykes are 50 m thick at the base and 15 m high with a flat top. This Delta Works remains one of the largest construction projects in human history, and has very successfully protected the Netherlands from inundation by sea.

Let Coastal Works commence

Let us draft a master-plan to combat the rising sea. And let me propose a name for this master-plan, the Coastal-Works, which would include all the co-ordinated projects of coastal-engineering, delta-works, river-engineering of both east and west coasts of India. The rising seas, presently, do not threaten the entire coast-line of 5,700 km of the mainland of India, therefore, let the very first stage of our endeavours be focused on the most vulnerable parts, which are the numerous low-lying river deltas. Protection of these deltas from the ravages of the rising seas would require a well co-ordinated construction of an extensive network of dykes, embankments, dams and revetments. Building materials for these earthern structures could be sourced primarily by dredging sands from riverbeds and sediments from the shallow continental-shelf of the seas.

The first line of defence against the rising sea would be a massive flat-topped outer-dyke of comparable cross section to that of the outer-dykes of Holland, at 15 m high and 50 m wide at the base. The flat-top of the outer-dyke could be as broad as 8 m and host a two-lane highway. The outer-dyke would be accompanied by a substantial inner-dyke running essentially parallel to the first, and a very large number of equally substantial cross-dykes to link the inner- and the outer-dykes. Building of the network of dykes will create a large number of fresh-water lakes of different shapes and sizes depending upon the topography, which have to be managed carefully. In certain localities substantial strips of land of the continental shelf, currently under sea-water, could even be reclaimed.

The combined length of the network of dykes of Coastal Works would easily be ten times longer than that of their Dutch counterpart. The cost of Coastal Works will be in thousands of billions of rupees, which is expensive but if we do not take up this project the losses will be in thousands of trillions of rupees. The Coastal Works will take decades to complete, but let us not delay the start.

At the moment in India, on certain coastal areas of the east as well as the west, coastal-engineering projects are ongoing. Although these projects were not designed for combating sea level rise, their scopes could be expanded to lay the foundations for Coastal Works. Say for example dredging on coastal waters is going on at Dhamra of Orissa for setting up a new sea-port, and at Chilika Lake for keeping a channel open from the sea to the lagoon. These kinds of dredging could be expanded and modified to build the outer-dykes. Moreover, the Ministry of Environment of the Government of India has initiated an Integrated Coastal Management Plan (ICMP) for the Orissa coast. This plan proposes to act along two stretches, a 40 km one from Gopalpur to Chilika Lake, and an 80 km tract from Paradip to Dhamra. ICMP is a commendable programme designed to prevent coastal erosion, and the scope of this programme could be substantially expanded. At certain other coastal localities where towns and villages are under immediate threat from the sea and storm surges, the government is constructing dykes along the coast to protect them. These are good and welcome moves, but this piecemeal approach is not enough. It is time now to draft a master plan for the entire country, and initiate the appropriate projects.

As I write this article, Chandrayana -1 has soared high into the space, and would complete the lunar mission over the next few days; an immense achievement indeed. I want my readers to remember that this very successful Indian space programme had a very humble beginning four and a half decades ago in 1962. Our space programme has helped immensely in raising the quality of life of the entire nation. Now the nation must pay some attention to protect the landmass by taking up Coastal Works. If we manage properly, India will continue to prosper very substantially even in this era of global warming. I must however, record that quite difficult a task it is, to motivate a people who are so utterly obsessed with the present that they can hardly even visualise tomorrow, let alone a few hundred years from now.

Our Indian empires of the past were the most prosperous and successful sea-faring nations. The Kalinga Empire of the east coast was immensely prosperous due to maritime trade and commerce with far off lands of Java, Sumatra, Sinhala, Malaya, Siam, and many other countries of the world. All those thousands of years ago, perhaps tens of thousands of years ago, Kalingan merchants and scholars settled in those far off lands to set up urban centres, so much so that till this day the natives of Malaysia are called Kalingas, and Ramayana as Ramakatha is celebrated in Java and Sumatra. I would also like my readers to recall that Emperor Ashoka"s sons Prince Kunala and Prince Mahendra, and daughter Princess Sanghamitra carried the sacred Bodhi plant to Sinhala from a sea port of Kalinga to spread the message of peace and love, following the Kalinga war in 261 BC i.e. 2,270 years ago. The Pandya and Chola Empires of Tamil Nadu were major maritime powers way before the advent of Christian Era. I would also like to record that these empires of the past were adept in river-engineering and very likely on coastal-engineering as well. The oldest surviving dam of the world, the Grand Anicut on the Cauvery River of Tamil Nadu attests my assertion. This 330 m long, 4.5 m high and 20 m wide dam was built across the Cauvery by King Karikalan of Chola Dynasty almost two thousand years ago in the first century AD to irrigate around 280 square km of land in the fertile delta, and it is still functional.

We have a rich history in building dams, managing water, and dealings with the sea. And we did all this even before Holland was conceived as a nation. So if the Dutch could construct their Delta Works to protect their land that lies 6 m below sea level, we could do better and safeguard Mother India from the threats of the rising sea. And in years to come we could export our expertise of Coastal Works to other countries in distress.

Let the Coastal Woks commence.


Dr Nachiketa Das

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References & Notes:

(This article was first published in an online newspaper from Orissa, www.hotnhitnews.com on November 2, 2008; posted on www.sulekha.com on November 5, 2008. The author retains the copyright.)




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