Sea-Level Rise in Bangladesh

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A Note On

Sea-Level Rise in Bangladesh

Bashir A. Khan

INTRODUCTION

Bangladesh, which was a part of Pakistan before 1974, is an important country of South Asian region. Its most immediate neighbors are India and Myanmar. It is located at the upper side of the Bay of Bengal. Bangladesh is the world's eighth-most populous country, the fifth most populous in Asia and the third-most populous among Muslim-majority countries⁽¹⁾.

Fig 1: Map of Bangladesh

Bangladeshi coastal plains or Bengal Delta, are one of the most fertile

regions not only in South-Asia but also the whole of Asia or even the whole of Earth and it includes three of Asia's largest rivers, including the Ganges (Padma), Brahmaputra (Jamuna) and Meghna. The Ganges delta is formed by the confluence of the Ganges (local name Padma or Pôdda), Brahmaputra (Jamuna or Jomuna), and Meghna rivers. The Ganges unites with the Jamuna and later joins the Meghna, finally flowing into the Bay of Bengal. The alluvial soil deposited by the rivers when they overflow their banks has created some of the most fertile plains in the world ⁽²⁾.

The country is also home to the Sundarbans, a sanctuary of the Bengal tigers and the world's largest mangrove forest. The eastern region includes a lush tea growing area and the mountainous Chittagong Hill Tracts. The country's 600 km (370 mi) coastline includes the world's longest natural beach, a coral reef and numerous islands. The climate is prone to monsoon floods and cyclones. Bangladesh is one of the most densely populated countries in the world, ranking alongside South Korea and Monaco⁽³⁾.

Bangladesh is predominately rich fertile flat land. Most parts of Bangladesh are less than 12 m (39.4 ft.) above sea level, and it is estimated that about 10% of the land would be flooded if the sea level were to rise by 1 m (3.28 ft.). It is estimated that ~17% of the country is covered by forests and ~12% is covered by hill systems. The country's hoar wetlands are of significant importance to global environmental science⁽⁴⁾. Straddling the Tropic of Cancer, Bangladesh's climate is tropical with a mild winter from October to

Fig 2: Rice Farming in Coastal Zones

March, and a hot humid summer from March to June. The country has never recorded an air temperature below 0 °C, with a record low of 1.1 °C in the north west city of Dinajpur on 3 February 1905⁽⁵⁾. A warm and humid monsoon season lasts from June to October and supplies most of the country's rainfall. Natural calamities, such as floods, tropical cyclones, tornadoes, and tidal bores occur almost every year⁽⁶⁾ combined with the effects of deforestation, soil degradation and erosion. The cyclones of 1970 and 1991 were particularly devastating. A cyclone that struck Bangladesh in 1991 killed some 140,000 people⁽⁷⁾.

Fig 3: Fish-catching Game in Coastal Areas

The land and the people of Bangladesh have a long and rich relationship with water. The country has many long and deep rivers and thousands of natural and man-made canals are scattered throughout the land. The economy is primarily based upon fishing and cultivating rice, jute, wheat and corn. The water is both companion and, occasionally, a bitter enemy of the Bengali population throughout the history, but people are brave and always faced the flooding problems with a smile.

Sea-Level Rise:

Causes and Affects

Climate change is being widely discussed in the world due to its timely and immediate importance for the humanity as a whole. However, some local regions are more prone to climate change effects than others. The expanding industrialization and other consequential human activities are making the world hotter and hotter every day. The net result is what is generally called Global Warming. Actually both terms mean the same affect. It is obvious that a consistent rise in atmospheric temperature results in the rise of sea-water level.

This rise affects low lying coastal regions and inhabitants of the respective deltas. Up to 1990 this concern had become so urgent that Intergovernmental Panel on Climate Change made a collaborative study and estimated that if the same pace of human industrial expansion is retained in the near future the world would be 3.3^ºC warmer by the end of the next century (i.e., by ~2090). As a consequence, with the rise in this much temperature, sea level will rise appreciabely due to thermal expansion of water and glacier melting.

Bangladesh is a flood plain delta with a large number of rivers forming a complex web of “water tubes”. Its geographic setting is such that it forms a slope running from north to south. The whole coast runs parallel to the Bay of Bengal, forming about 710 km of coastline⁽⁸⁾. Many densely populated districts of the country are subject to direct affect by the expected sea-level rise.

Fig 4: Glacier Melting Due to Global Warming

This means that millions of people will be directly affected by the dangers of level rise in the coming decades. The coastal zone covers some 47 thousand square kilometers of land area, which comes out to be about 32% of total land mass of the country. Water area covers some 370 km from the coastline, estuaries and the internal river water. A wide industrial area called Exclusive Economic Zone (EEZ) is also treated as a coastal zone.

Bangladesh is now widely recognized to be one of the countries most vulnerable to climate change. Natural hazards that come from increased rainfall, rising sea levels, and tropical cyclones are expected to increase as climate changes, each seriously affecting agriculture, water and food security, human health and shelter. It is believed that in the coming decades the rising sea level alone will create more than 20 million climate refugees⁽⁹⁾. Climate change is causing increasing river erosion in Bangladesh, threatening an estimated 20 million people.

During the twentieth century, global mean sea level rose at an average of 0.07 inches (1.8 millimeters) per year, but from 1993 to 2003, that rate increased to 0.12 inches (3.1 millimeters) per year. Scientists attribute the rising sea levels to expansion of the oceans as they warm, as well as to the melting of mountain glaciers and the Greenland and Antarctic ice sheets^{(10, 11, 12)}. Bangladesh, one of the world's most populous countries, is highly vulnerable to the effects of sea-level rise—including more salinization of both ground and surface waters. The deltaic plains of the Ganges, Brahmaputra, and Meghna rivers compose most of the country's land area,4 and the vast majority of the coastal zone is at an elevation of less than 16 feet (5 meters).

Local sea-level rise of as much as 1 inch (25 millimeters) per year has been recorded in sections of the Ganges-Brahmaputra Delta. Most deltas experience natural sinking and settling of land (subsidence), which can increase relative, or local, sea-level rise. Human interventions such as extraction of groundwater can speed up subsidence, as has been the case in the Ganges-Brahmaputra basin. Local sinking and groundwater extraction can allow seawater to creep inland, displacing coastal plant and animal communities that depend on brackish or freshwater. Encroaching seawater and salty groundwater may also increase soil salinity, which can hinder growth of crops⁽¹³⁾. For example, increased salinity inhibits rice growth and can lower rice yield⁽¹⁴⁾.

By mid-century, more than 3 million people stand to be directly affected by sea-level rise in the Ganges-Brahmaputra Delta⁽¹⁷⁾. In a worst-case scenario, Bangladesh could lose nearly 25 percent of its 1989 land area by around 2100. Climate change is projected to cause further sea-level rise during this century and beyond. If we do nothing to reduce our heat-trapping emissions, global sea level is projected to increase some 23 inches (59 centimeters) over recent average levels by the end of this century⁽¹⁸⁾.

However, if we make significant efforts to reduce emissions, sea-level rise could be limited to about 15 inches (38 centimeters) by the end of this century. Recent evidence of higher rates of global sea-level rise suggests that these projections may be low. and regional variations in sea-level rise are expected to continue⁽¹⁸⁾.

In Bangladesh, the impact of sea-level rise may be worsened by other effects of global warming, such as variable precipitation, more frequent droughts and floods, and shrinking of the glaciers that supply water to the rivers of the delta. Reduced rainfall during the dry season, for example, can increase the salinity of rivers through encroaching seawater that moves upstream during periods of low flow⁽¹⁹⁾.

Human activities such as shrimp farming and damming of rivers are also expected to intensify the effects of sea-level rise. Dams can retain sediment that would otherwise replenish eroded or subsided land in the river delta⁽¹⁵⁾. More dams are planned in Asia, which are likely to increase erosion as well as relative sea-level rise, and might worsen water shortages and extend the area affected by salinity during the dry months.⁽¹⁶⁾.

With the added pressure of rising air temperatures, rice production in Bangladesh could drop by 8 percent, and wheat production by 32 percent, by the middle of this century⁽³^,18). Unless we act now to cut our heat-trapping emissions, and take steps to prepare for the warming already projected to occur in the coming decades, the food and freshwater supply of millions of people in the Ganges-Brahmaputra Delta is likely to be in danger.

Response to Sea-Level Rise:

Adaptation & Mitigation

Nature is Nature and human beings are so weak against it that individual and small scale effort to meet the big natural challenges being faced by countries or big geographical regions do not produce appreciable results. The challenges of sea level rise to the coastal regions are so diverse, complicated and daunting that potentially no nation, however economically fit, can stand to them in a short period (i.e., a few decades) of time. Very extensive studies, plans and budgets as well as civic understanding is involved along with a social and political will of the people of the concerned region. Bangladesh is a small (area wise) country and its populational and food problems are so daunting that it is almost impossible for it to deal single-handedly with the effects of sea-level rise. The major option for this region, in the opinion of the current writer, is to pay high attention to minimize the effects of the sea-level rise affects in the next two or three decades.

In the words of the main author of the legendary paper on the preventive measures of the sea level rise⁽²⁰⁾, only two options, Adaptation and Mitigation, are available to communities facing this challenge. What does these terms mean, can be quoted in the words of the main author as: “Mitigation is a response to the broad issue of climate change and involves reducing or stabilizing greenhouse gas emissions or levels, in order to mitigate changes in climate…….Adaptation refers to adjustments in ecological, social and economic systems in response to actual or expected climatic stimuli, their affects or impacts”.

The mitigation requires very big budgets while adaptation can be done with lower expenses. For this poor country, Bangladesh, both options are necessary while adaptation should be done first before mitigation as an immediate control measure. Adaptation is a local effort while mitigation requires co-operation of the neighboring countries as well as the world community. But, How to implement these measures ? Following is a brief discussion of both of these control measures.

Adaptation:

The main goal of this strategy is to minimize the effects of sea level rise on the living organisms of the area including human beings. To address the sea level adaptation:

1. Government policies have to be changed that could lessen pressure on all kinds of resources along with the managerial control.

2. As most of the coastal population depends on the fish-catching and agricultural farming, the adaptation option should be stressed on these two sectors to overcome the issues of the anticipated issues. A practical solution is that the foreign exchange earned by the coastal fisheries industry could be invested for the development of coastal fisheries sector. This investment may be used for disaster preparedness activities, special weather forecasting and further research.

3. The fishermen and their young family members should be specially trained and equipped with necessary tools to be used in the event of disaster. A fixed amount of their income may be deducted and put into government saving schemes which can be used by them in the difficult times of disaster.

4. Cheap television and cellular phone facilities may be provided to the coastal facilities so that they remain always informed about the weather forecasts.

5. Since salinity is increased with the rising sea level, good research in the universities and government institutions may be done to find out salinity tolerant grain and fish species. After creating and selecting different salinity tolerant species the fishermen may be trained about breeding, cultivation and harvesting of the species.

6. For the forests located near the coastal areas new salinity-tolerant trees should be developed and introduced. This could be done by investing into research, as indicated before. Mangrove afforestation should be adopted to protect soil erosion because its roots help to compact soil. The decomposition of dead leaves of mangrove will add organic matter to the soil turning coastal land more fertile.

7. The research activities should also include the development of raw materials for coastal resources dependent industries.

8. Efforts for fresh water availability to coastal zone population may be enhanced as the coastal zone is threatened by water born cholera and diarrhea diseases. The continuation of good health of fishermen and farmers of the coastal communities is vital for saving of budget which is otherwise spent on the maintenance of health facilities than other useful sectors.

Mitigation:

It is often said that prevention is better than cure. It is fully true in all senses. Mitigation is the act of prevention. To implement this option, the following is recommended by the authorities of the field:

1. The control on the emission of greenhouse gases is the prevention of climate change and ultimately the sea level rise. Since industry is not much diverse in Bangladesh it emits a very small amount of greenhouse gases, however, still it should try to cut it down in the future when more industrial units are built in the country. Control of deforestation and fossil fuel is necessary to achieve this goal.

2. Some of the greenhouse gas emission reduction measures include

2.1 Demand reduction and/or efficiency improvement

2.2 Substitution among fossil fuels

2.3 Switching over to nuclear energy option

2.4 Switching over to biomass option

2.5 CO₂ scrubbing and removal

2.6 Afforestation

3. The country should think to seek and use possible renewable resources to generate electric power. In the coastal areas and in many inland areas favorable natural conditions like sufficient sunshine and wind speed exist for the promotion renewable energy in the country.

4. As of solar power generation, in Bangladesh average absorbable solar radiation is 0.193 kW/m². The country has an area of 144,000 square km. This means that The country receives a constant supply of 28 TW⁵energy from the sun, which is nearly 200kW per capita for a population of 140 million. The annual per capita consumption of electricity in Bangladesh is estimated as 112 kW, which is available only for 18% of the population. Comparative to the present electricity consumption, solar energy availability is a big amount of energy. A World Bank survey reports that 500,000 households of Bangladesh may be potential market for solar home System ^(21,22,23).

5. Afforestation in the coastal zone has potentiality to increase forest cover in the country. An extensive afforestation effort will act as carbon sink. For this purpose, as already said elsewhere, mangrove plantation in the zone will be very beneficial means of coastal protection against cyclones, storm surges and soil erosion

References

1. Wikipedia Article : https://en.wikipedia.org/wiki/Bangladesh.

2. Suvedī, Sūryaprasāda (2005).”International watercourses law for the 21st century”, Ashgate Publishing, Ltd. pp. 154–166. ISBN 0-7546-4527-4.

3. Green, Jen (2009). “Coastlines Around the World”. The Rosen Publishing Group. pp. 26–. ISBN 978-1-4358-2957-2.

4. Ali, A (1996). "Vulnerability of Bangladesh to climate change and sea level rise through tropical cyclones and storm surges". Water, Air, & Soil Pollution 92 (1–2): 171–179. doi:10.1007/BF00175563.

5. "Map Of Dinajpur". kantaji.com. Archived from the original on 13 July 2011. Retrieved 17 April 2015.

6. Alexander, David E. (1999) [1993]. "The Third World". Natural Disasters. Dordrecht: Kluwer Academic Publishers. p. 532. ISBN 0-412-04751-9. Retrieved

2 May 2008.

7. "Beset by Bay's Killer Storms, Bangladesh Prepares and Hopes". Los Angeles Times. 27 February 2005

8. CZPo (2005), “Coastal Zone Policy”, Ministry of Water Resources, Government of the Peoples Republic of Bangladesh, Dhaka.

9. "After Major Cyclone, Bangladesh Worries About Climate Change". PBS News Hour. 28 March 2008. Archived from the original on 22 January 2014.

10. "Gini Index". World Bank. Archived from the original on 16 February 2015. Retrieved 2 March 2011.

11. "Human Development Report 2015" (PDF). United Nations. 2015. Retrieved 14 December 2015.

12. “The Pearson Concise General Knowledge Manual 2012”. Pearson Education India. pp. 11–. ISBN 978-81-317-6191-5.

13. "Gangaridai, the wellspring of Bangladesh - Dhaka Tribune". dhakatribune.com. Retrieved 9 December 2015.

14. http://www.gutenberg-e.org/yang/pdf/yang-chapter2.pdf

15. Nicholls, R.J., et al., (2007), “Coastal systems and low-lying areas”, In: Climate change 2007: Impacts, adaptation and vulnerability. Contribution of Working Group II to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. pp. 315-356.

16. Cruz, R.V., et. al., (2007), Asia. In: Climate change 2007: Impacts, adaptation

and vulnerability. Contribution of Working Group II to the Fourth Assessment

Report of the Intergovernmental Panel on Climate Change. Cambridge

University Press, pp. 469-506

17. Ericson, J.P. et. al., (2005), “Effective sea-level rise and deltas: Causes of change

and human dimension implications”., Global Planetary Change Vol. 50:63-82.

18. Solomon, S., D. et. al., (2007), Technical summary. In: Climate change 2007:

The physical science basis. Contribution of Working Group I to the Fourth

Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge University Press, pp. 20-91.

19. Nishat, A. (2008)., “Climate change and water management in Bangladesh”,

Conference on Global Climate Change and Its Effects, International Union for

Conservation of Nature, Dhaka.

20. Smith, et. al., (1999), ”The Science of Adaptation:A Framework for Assessment,

Mitigation and Adaptation Strategies for Global Change”, pp. 199-213.

21. Islam & Huda (1999), “Proper Utilization of Solar Energy in Bangladesh”, Renewable

Energy, Vol. 17, pp. 255-263

22. Samrina, N, (2004), “Energy Security for Bangladesh”, Retrieved from:

http://www.acdis.uiuc.edu/Research/OPs/Samrina/contents/part1.html on

20th Nov. 2005.

23. Sarkar, et. al., (2003), “Issues Relating to Energy Conservation and Renewable Energy in

Bangladesh”, Energy for Sustainable Development, Vol. VII (2).

geology papers

Sea-Level Rise in Bangladesh