THE CLIMATE CHANGE OF SUNDARBANS

 THE CLIMATE CHANGE OF SUNDARBANS

Abstract - Sundarbans is a World Heritage Site and one of the largest mangrove forest present on earth. It serves as home to various species which includes tigers, About 50 lakh people and various exotic animals and birds. Research has shown that the Sundarbans have absorbed 42 lakh tons of carbon dioxide. The world-famous Royal Bengal Tigers and the beautiful spotted deer of the Sundarbans are known to all, as the Royal Bengal Tigers are found only in the Sundarbans, which attracts many tourists. The tourism sector can play a very important role in the development of Bangladesh's economy as it is the world's largest sector generating foreign exchange and revenue for the host country. Due to climate change caused by global warming and other human activities, the Sundarbans are facing several challenges. Rising sea levels are causing islands to disappear and the increasing salinity of the water and soil poses a significant threat to the health of the mangrove forests and the quality of the soil and crops. Deforestation is increasing in most areas of Sundarbans, which will eventually lead to loss of biodiversity. The problem of overfishing has put a lot of pressure on the surrounding area. The fish population is declining due to the combination of overfishing and changing environmental conditions.

 

Keywords - Sundarbans, Bangladesh, Cyclone, Deforestation, Adaptation, Mitigation

 

I. INTRODUCTION

With an area of about 32.9 lakh square kilometres, India stands 7^th in the world in terms of area. Although the country covers a large geographical area and more than 139 crore people live there, about 24% of India is still covered by diverse forests. In the north-east of India lie the Sundarbans, the largest contiguous mangrove forest in the world, covering about 9.6 thousand square kilometres. Of this, 5.4 thousand square kilometres are reclaimed land and 4,267 square kilometres are protected mangrove forests. Another 6 thousand square kilometres of contiguous mangrove forests are located in neighbouring Bangladesh. The Sundarbans administrative region of India is located in West Bengal a state of India. The Sundarban ecosystem is one of the few most preserved and taxonomically diversified ecosystems in the Indian subcontinent. The entire area is a collection of river channels, streams and islands, totaling 102 in number. Of these, 54 islands are inhabited while the remaining 48 are forested. The name Sundarbans is believed to be derived from the Heritiera fomes tree, one of the most abundant mangrove trees here called 'Sundari'. About 20 decades ago, the Sundarbans were about 16.7 thousand square kilometres in size and were home to several species of animals such as the Javan rhinoceros, wild buffalo, swamp deer, bark deer and leopards. but the opportunities for tourism development are abundant due to the geographical location, beautiful nature, climate and friendly people. Tourism is one of the fastest growing industries in the world, which has been evident in the last few decades. The tourism sector in Bangladesh is not yet very developed but can be developed well with the help of the government, skilled people, international organisations, private organisations, natural resources and proper marketing plan. Natural resources are the most important sources for the development of tourism in Bangladesh. Tourist attractions include: archaeological sites, historical mosques and monuments, resorts, beaches, picnic spots, forests and various wildlife. Tourist activities include fishing, water skiing, river cruises, hiking, rowing, sea bathing and many others. However, lacking irrigation facilities and basic infrastructure, agricultural practises are primitive and dependent on seasonal rains, resulting in poor harvests and providing a volatile source of livelihood.

 

II. IMPORTANCE

The Sundarbans are located in the delta of the three rivers i.e., Ganga, Meghna & Brahmaputra, has a significant part of the world's largest contiguous block of mangrove forests and biodiversity. It is home to 300 plant species and 425 animal species, including the Ganges dolphin (Platanista gangetica) and the Irrawady dolphin (Orcaella brevirostris). The Sundarbans are home to a high level of biodiversity and the occurrence of endangered and critically endangered species, including the only population of the critically endangered Royal Bengal Tiger, which lives in a coastal mangrove habitat. The Sundarbans account for 85 % of all mangrove found in India, including 63 plant species of the country's 69 mangrove plant species. The Sundarbans are believed to harbour up to 140 mangrove and coastal plant species, of which at least seven are threatened and require immediate conservation action. The local population depends heavily on the mangroves for fodder, firewood, tannins, fish, honey and medicinal herbs. The mangroves release 6 thousand tonnes/ha of waste in the course of a year, accounting to large amounts of Wild Bengal.

 III. THREATS

The Sundarbans area is a cyclone-prone, monsoonal and low-lying area where climate changes have significant impacts on the area, plants, animals and the people living there.

A. Rising Temperatures

Between 1985 and 2012, water temperature in the Sundarbans was observed to have risen at an accelerated rate of 0.5o C per decade, compared to the observed global warming of sea surface temperature of 0.06o C per decade. This accelerated increase in ocean temperature has serious implications for aquatic life. This change has a major impact on the Sundarbans area as it is an estuarine delta. It is also affecting the health of the mangrove ecosystem.

B.       B. Rising Sea Levels

Over the last 3 decades, sea levels have risen almost twice as fast as the global mean. This is due to a combination of many factors, including the lifestyles of land dwellers. As plants are constantly submerged in higher water due to sea level rise, they are smaller and thiner and have less branches and leaves, resulting in a low rate of photosynthesis and regeneration of mangroves. Sea level rise also affects the availability of sediments, which directly affects the establishment of new groves.

C.       C. Cyclones

It has been observed that the intensity of cyclones that hit the Sundarbans between 1950 and 2010 has increased. Recent studies suggest that the increase in intensity of the cyclones is due to an increase in sea surface temperature. During Cyclone Aila, a 400 km long causeway was breached and waves overtopped the height of the causeway and entered the floodplains. The sea water trapped more than 20 lakh people for several days, affecting not only agriculture but also the consumable water supply. Most of the homes were damaged. In addition, farmland became unproductive due to saltwater intrusion into the soil. The frequent property damage and crop failures due to cyclones and storms have left much of the population impoverished. As a result, heavy migration to the cities is reported from here.

D.      D. Increase in Salinity

Impact on agriculture studies indicate that over the last twenty years, water flowing in the eastern rivers of the Sundarbans has declined, resulting in increasingly high salt and sulphate concentrations in seawater. The decline in freshwater discharge has affected the growth of mangroves. In addition, agriculture is affected by high soil salinity caused by high tides, cyclones and storm surges, as well as problems with stagnant water, sometimes even beyond the monsoon season.

E.       E. Change in Agricultural Structures

According to the Government of West Bengal data of 2009, the agricultural area has shrunk from 2,149.615 square kilometres to 1,691.246 square kilometres between 2002 and 2009. The cultivated area suffers from low intensity of cultivation as only rice is grown seasonally and horticultural crops are rarely grown. Moreover, only 12% of the cultivated area in the Sundarbans is irrigated by rainwater ponds, cisterns and canals; most of the agricultural land is rainfed. It has been observed that rainfall has become erratic and its intensity has increased, further harming agricultural yields. As the population is constantly growing, agricultural production in the region cannot meet the demand. In the past, the major economic activity of rain-fed rice cultivation was made possible by the construction of dams to keep out the brackish tidal waters and the cultivation of salt-resistant rice species such as Hamilton & Matla. These species could be grown on the elevated sections of the islands even without dams. However, in their search for the six locally known salt- tolerant rice varieties, the scientists found only two varieties. The other salt-tolerant rice species have probably been lost to the onslaught of the Indian "green revolution".

F. Deforestation

Between 1775 and 1970, forests were continuously cut down and land reclaimed in the Sundarbans region. t It was observed that five percent of the forest area was lost between 1989 and 2009. This deforestation has exacerbated human- wildlife conflict, wiped out several species locally and contributed to the biological loss of the region. Moreover, deforestation has not facilitated self-sustaining agriculture in the floodplains as they are submerged in salty water during floods.

G. Pollution

Due to heavy residue and solid waste thrown from the adjoining towns, the rivers in the Sundarbans don’t get fresh water from the upstream Ganga and are mainly fed by the tides. The Sundarbans gets an additional supply of fresh water during the rainy season, which lasts from May to October. There has been a pronounced ecological transformation in this delta due to massive discharges of untreated domestic and industrial effluents from tributaries, as well as the disposal of contaminated silt from port dredging and the rapid development of the Haldia port complex, a major oil hub in eastern India. The Sundarbans Delta has become vulnerable to chemical pollutants such as heavy metals, which may have altered the geochemistry of the estuary and affected the local coastal environment. Due to a variety of inputs such as agricultural runoff, sewage and wastewater discharges, and agricultural wastes, maximum concentrations of organochlorine pesticide residues have been detected at sites along the mainstream of the Hugli (Ganges) estuary. This has catastrophic effects on biodiversity in the mangroves.

IV. EFFECTS OF CLIMATE CHANGE

Climate change is having a major impact in the mangrove-dominated delta complex of the Indian Sundarbans. The melting of the Gangotri Glacier in the Himalayan Mountains and various anthropogenic influences have accelerated this phenomenon over the last two decades. Two important indicators, namely temperature and salinity of surface water, which were investigated in the present study, showed significant correlations with climate change and caused significant changes in hydrological parameters over a period of 27 years. Due to the different geographical conditions in the western and central sectors of the delta complex, the footprints of climate change were perceived in different patterns and magnitudes. Surface water temperature showed an increasing trend in both sectors (6.14% and 6.12% increase in the western and central sectors, respectively). Salinity showed contradictory trends in the western and central sectors, which can be attributed to the dilution of the system regulated by the Farakka barrage. The blockage of major rivers in the central Indian Sundarbans by heavy silt and solid wastes from the adjoining city of Kolkata posed serious problems to the islanders due to rising salinity. There is also a marked shift in fish diversity, with more trash fish in the central sector. Such events can seriously affect the livelihoods of the local population.

V. ADAPTATION AND MITIGATION STRATEGIES 

Adaptation and mitigation complement each other. Adaptation addresses the consequences of climate change, while mitigation addresses the causes. Although Sundarbans is highly threatened by the impacts of climate change, it can hardly be blamed for this curse. Global warming, caused by unsustainable industrialisation and deforestation in other regions, is also affecting the Sundarbans region through rising sea levels and frequent cyclones in the Bay of Bengal. Therefore, adaptation strategies are more important here than mitigation measures, as the latter have a very limited scope. However, the mitigation strategies that need to be resorted include the following:

1)Strengthening conservation mechanisms to prevent further deforestation and degradation of mangroves within reserved forest areas.

      2)Plant new trees in the villages, along the embankments and in the degraded mangrove areas to sequester carbon and protect the embankments from storm surges and tidal erosion

3)Stop the conversion of mangrove areas to brackish water aquaculture (preferably shrimp farming, which is particularly vulnerable to viral infestation)

      4)Strengthen and maintain nearly 3500 km of dams around 54 non-forested islands

     5)Prevent discharge of untreated sewage from upstream cities and industries into the Sundarbans estuary, which can cause bioaccumulation of conservative pollutants in  fish tissue.

Adaptation strategies are of utmost importance in the surrounding villages of the Sundarban mangrove forest, as the inhabited region is one of the most densely populated regions in the country. As a large part of the population, especially in the buffer zone of the mangrove forest, depends on the natural resources of the Sundarban estuary for their livelihood, the development of alternative livelihoods in a changing climate scenario is of utmost importance. The Sundarban region receives around 2000 mm of rainfall per year, but the sweet rainwater is lost as runoff into the saline tidal rivers, while there is hardly any year-round freshwater available in the villages for drinking or irrigation purposes. This naturally available water resource can be turned into its strength when planning adaptation strategies.

1) Collect rainwater in villages by building irrigation canals and ponds. The stored rainwater can be used both as drinking water and as irrigation water for growing secondary crops in dry months. Digging canals and ponds and cultivating post-monsoon crops will create many jobs during the winter season and reduce biotic pressure on the mangrove ecosystem.

     2)Encourage the cultivation of salt-tolerant indigenous rice and vegetable crops that serve as insurance against the vagaries of rainfall and flooding.

    3)Emphasise the cultivation of crops such as chilli, sunflower, etc., which are less perishable and can be stored and marketed as required.

   4)Construction of multi-purpose cyclone shelters to provide shelter to villagers when villages are inundated during storm surges. At other times, these buildings can be used as schools/community centres for the villagers.

  5)In order to make the villagers more independent of the mangrove forests, e.g. by fishing, collecting shrimp seeds, etc., the women of the village are trained in village activities such as sewing, raising chickens, ducks and pigs, and raising seedlings for reforestation. This has catastrophic effects on biodiversity in the mangroves.

 

VI. CONCLUSION

The most important details in this text are the key issues that need to be considered in formulating adaptation/mitigation strategies for the Sundarbans region. Conservation of mangroves helps sequester atmospheric carbon, but local people lose their livelihoods. Unless the international community and developed nations develop mechanisms to offset the costs of conservation, efforts to preserve this rich mangrove estuary may not be sustainable. The impact of global warming from projected sea level rise on the Sundarbans is an unavoidable phenomenon. Mitigation measures must be taken primarily at the global and local levels, and the adaptation strategy must include the participation of global and local communities. In addition, people living around the mangrove forests must be provided with sustainable alternative livelihoods to cope with increasing salinity in the PH tonne 347 region.

The key details in this text are that regular and scientific maintenance of the embankments around the island villages can help protect the villagers from storm surges and cyclones. The introduction of indigenous rice varieties and salt-tolerant rice varieties/ vegetables/ crops are also important adaptation strategies. Rainwater harvesting is also an important adaptation strategy, as the area receives an average of about 2000 mm of rainfall per year, but the freshwater is lost as runoff into tidal rivers. To create jobs, other livelihood opportunities and skills development training need to be taken up, but all these socio-economic activities need a large amount of financial support to start with. In addition, people in the region need to be compensated through REDD + projects. The study has shown that it is possible to conserve the mangrove flora and fauna of the Sundarbans through the active participation of the local people. The global community cannot escape its commitment to conserving this world heritage site and one of the largest sinks of atmospheric carbon.