4sea, Oceans

Sea Level Rise in the Indian Ocean

This article is part of the 4sea Project.

Case study of Bangladesh

Bangladesh, a country of around 164 million people, is situated in the maritime territory of the largest river delta in the world, Ganges-Brahmaputra, at the head of the Bay of Bengal. With nearly two-thirds of the country being less than 5 meters above the sea level, Bangladesh is widely recognized as one of the most vulnerable countries to climate change.1 As the sea surface temperatures have risen significantly faster in the Bay of Bengal (5 mm yr-1 and more) than for the global average (3.2 mm yr-1) for the past decades, Bangladesh has suffered one of the fastest increases of sea level rise in the world.2 Along the shoreline of Bangladesh tide-gauge records have reported sea-level rise rates between 6 and 20 mm yr-1, which highlights the spatial variation of the dynamic coastline of the country.3


Being located in the pathway of the tropical monsoon in the Indian Ocean with heavy rains during summer season, Bangladesh suffers tropical cyclones, floods and strong storm surges on a yearly basis. Additionally the glaciers in the Himalayas are melting, adding excess water in the rivers flowing to Bangladesh. The largest river delta in the world caters for very fertile alluvial delta soils, perfect for agriculture. Hence, most Bangladeshis have settled along the coastal areas of the three largest rivers, Brahmaputra, Ganges and Meghna rivers as well as on the shoreline facing the Bay of Bengal. Unfortunately, saltwater intrusion as well as cyclones and storm surges have contaminated groundwater and degraded farmland in many of the low-lying areas endangering food safety and access to clean drinking water for a large part of the population.4

According to the Bangladesh Climate Change Strategy and Action Plan 2009 created by the Bangladeshi government, as much as up to 25 % of the country is inundated during an average year and as much as up to 60 % every fourth to fifth year.1 As Bangladesh is considered one of the poorest and most densely populated countries in the world, the frequent natural disasters have lead to considerable loss of life, economic assets as well as damage to infrastructure. This deteriorates both the positive economic and social development that Bangladesh has witnessed for the past decades, with a rising GDP and food production, growing economy, a higher human development index and a decline in population growth and child mortality.1

winter-morning-2310541_1920Close to 50 million people are still living in poverty and are therefore most vulnerable to the more frequent natural disasters facing Bangladesh.1 These people are mostly settled in the more fragile and remote areas on the river islands formed by sedimentation from the rivers, also known as chars, as well as on the low-lying coastline often struck by tropical cyclones and storm surges. The latest tropical cyclone Mora, hit the south eastern part of Bangladesh in late May 2017, which caused 350 000 people to be evacuated and around thousands of homes to be destroyed.5 These kinds of deadly tropical cyclones are only expected to get stronger and more frequent in the Bay of Bengal because of climate change.

Additionally, coastal erosion and flooding have caused chars to completely or partly disappear, forcing yearly many tens and even hundreds of thousands of people to move elsewhere to already extremely densely populated areas, such as to other chars or to the slums in larger cities. Most of these char dwellers lack nearly all basic services such as clean water, electricity, health care and education and their displacement is seen as a start to possibly the largest mass migration ever witnessed in human history.6

Ecosystems are also altered to the impacts of rising sea level in Bangladesh. The Sundurbans mangrove forest, in the south-west of Bangladesh, is one of the largest of its kind and inhabits a large quantity of different flora and fauna, many of them endangered.7 This World heritage site provides livelihoods for many millions of Bangladeshis as well as shelter to the strong cyclones, storms and tidal surges that hit Bangladesh on a yearly basis. Because of human induced pressure and overexploitation as well as climate change impacts such as sea level rise, saline intrusion and stronger and more frequent cyclones, the Sundurbans is under threat.7 The biodiversity is declining as well as the vital Mangrove forests.

nature-2475761_1920-2The future doesn’t look too bright for Bangladesh. An approximately one meter rise in the sea level, projected as likely by the IPCC in the business-as-usual scenario, would submerge as much as 20 percent of the whole country.8 According to some scientists this rise could be much higher at the end of 2100 mainly because of the big uncertainties in the ice-sheet dynamics in the West Antarctic. Many tens of millions of people are expected to have to leave their homes, in some estimations even 50 million people, which would result in the largest mass migration in the history of humankind. Just to put it all into perspective, the war of Syria has displaced approximately 11 million people, of which around five million are now refugees in other countries.9

Many different adaptation and mitigation strategies have been taken into account such as the building of flood and cyclone shelters, building infrastructure adapted to the rising sea levels, coastal polders and embankments as well as adapting flood management schemes.10 Furthermore highly developed early warning systems have been integrated as well as the development of climate resilient crops. The country has managed to successfully implement many of the SDGs11 in their development policy and is often seen as an inspiration through their commitment and engagement for other less developed countries around the world.10 A country, whose contribution to the global greenhouse gas emissions only takes up a fraction, suffers some of the worst climate change impacts in the world, which are only expected to get worse.



About the author: Venni Arra is currently completing her bachelor’s degree in physical geography at Stockholm University and is doing her internship at CliMates in Paris for the Ocean and Climate change project 4sea.

This article has been written in the context of 4sea. 4sea, a project about the importance of the world oceans, addresses the interdependence between the oceans and climate change, entraining everyone to become ocean lovers – for now through articles and videos on this blog and in November on our own platform. 4sea is a joint project between the youth organisations CliMates, Youth for Ocean and Vitamin Sea. Love it? Stay tuned for our platform!

  1. MoEF, 2009. Bangladesh Climate Strategy and Action Plan. Ministry of Environment and Forests, Government of the People’s Republic of Bangladesh, Dhaka, Bangladesh. xviii. 76pp
  2. S. Unnikrishnan, A. G. Nidheesh, Matthieu Lengaigne. Sea-level-rise trends off the Indian coasts during the last two decades. Current Science, Indian Academy of Sciences, 2015, 108 (5), pp.966-971
  3. K.M. Saiful Islam. Rising Sea Level: Challenges ahead for Bangladesh, ICCCAD, [website], 2016 http://www.icccad.net/rising-sea-level-challenges-ahead-for-bangladesh/ (accessed 6 July 2017)
  4. The World Bank. Warming Climate to Hit Bangladesh Hard with Sea Level Rise, More Floods and Cyclones, World Bank Report Says, [website], 2013 http://www.worldbank.org/en/news/press-release/2013/06/19/warming-climate-to-hit-bangladesh-hard-with-sea-level-rise-more-floods-and-cyclones-world-bank-report-says (accessed 6 July 2017)
  5. United Nations Development Programme. UNDP responding to Tropical Cyclone Mora in Sri Lanka, Bangladesh, Myanmar and India, [website], 2017, http://www.undp.org/content/undp/en/home/presscenter/pressreleases/2017/05/31/undp-responding-to-tropical-cyclone-mora-in-sri-lanka-bangladesh-myanmar-and-india.html (accessed 6 July 2017)
  6. MNI Sarker, MA Ali and MS Islam (2015). Causes and possible solutions of poverty perceived by char dwellers in Bangladesh. International Journal of Natural and Social Sciences, 2(1): 37-41.
  7. UNESCO, The Sundurbans, [website] http://whc.unesco.org/en/list/798 (accessed 6 July 2017)
  8. Uzzaman Md. Arfan (2014). Impact of Sea Level Rise in the Coastal Areas of Bangladesh: A Macroeconoic analysis. Journal of Economics and Sustainable Development http://www.iiste.org ISSN 2222-1700 (Paper) ISSN 2222-2855 (Online) Vol.5, No.18, 2014 http://www.iiste.org/Journals/index.php/JEDS/article/viewFile/16037/16420 (accessed 6 July 2017)
  9. World Vision Staff, Syrian Refugee Crisis, [website], 2017, https://www.worldvision.org/refugees-news-stories/syria-refugee-crisis-war-facts (accesse 6 July 2017)
  10. Alam Shamsul (2017), Implementing SDGs in Bangladesh, The Financial Express, [website] http://www.thefinancialexpress-bd.com/2017/05/22/71227/Implementing-SDGs-in-Bangladesh (accessed 6 July 2017)
  11. United Nations, Sustainable Development Goals, [website], http://www.un.org/sustainabledevelopment/sustainable-development-goals/ (accessed 7 July 2017)

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