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Aftermath of Climate Variability on Fragile Coastal Ecosystems: Case Study of the Indian Sundarbans

Climate change is theorised to impact predominantly across economies, societies and ecosystems, escalating its pressure on all food supplies and livelihoods involving those in the fisheries and aquaculture sector.[[i]] Over the last few years, aquatic ecosystems, fisheries and fishers’ livelihood have been adversely affected by the climate instability manifested by acceleration of the sea level, higher incidence of flood, tropical cyclones, drought and growing water stress in several countries of the world.[[ii],[iii],[iv]] From the viewpoint of Asia, these computations are of great significance as anthropogenically disturbed areas, where the aquatic resources are in jeopardy by the climate irregularities, contribute to the livelihood of majority of fishers.

The numerous benefits that fisheries and aquaculture yield for the alleviation of poverty in these countries are unsettled by climate variability. Small‐scale fisheries, and particularly inland fisheries, have also often been abysmally recognized and marginalized with regards to the contribution to poverty reduction and food security. Several assessment reports showing strong assertions have been made by the Inter-governmental Panel on Climate Change (IPCC) about the phenomenon of escalated sea level rise (SLR) and more recurring severe events such as storm surges, coastal flooding, salinity intrusion, and cyclones. Sea-level deltaic and small island countries (SICs) have a specifically threatening adverse impact on freshwater fisheries and aquaculture. It has been predicted by the IPCC fifth Assessment Report (AR5)[[v]] that acceleration in sea level rise will compound inundation, erosion, storm surge, and other coastal menace.


The Indian Sundarban delta (between 21°40’–22°40’N and 88°03’–89°07’E) is a UNESCO promulgated World Heritage Site, and it is stretched out on the southern fringes of the State of West Bengal, where the Gangetic plain connects the Bay of Bengal. The steady accumulation of silt carried down by the Ganges, Meghna and Brahmaputra river system[[vi]] including its tributaries like Ajay, Mayurakshi, Kansai, and Damodar rivers[[vii]] has given rise to this river-mouth ecosystem. The Sundarban delta which is a plat of the world’s expansive mangrove ecosystem, is an archipelago of a variety of hundred islands, extended across 9,630 sq. km in India and 16,370 sq. km in Bangladesh.

The Sundarban provides shelter to over 4.4 million of the most unguarded and impoverished people in India. Nearly half of the apropos population exists below the poverty line (BPL), recording the highest poverty estimate in the blocks neighbouring the vast mangrove forest. Per capita income in the division is around 50 cents (U.S. Dollars) a day, which is half of what is frequently used as a benchmark of extreme poverty. There is a deficiency of rudimentary food security along with grovelling poverty; and nearly 6% of all ménages reported that they grazed on less than one square meal per day, with nearly 19% consuming only one meal per day.

There are comparatively more impoverished households in all 19 blocks of the Sundarban delta than the proportionate averages for India and West Bengal, moreover the percentage of BPL house-holds scales from 31% to 65% in these blocks.[[viii]] Around 80% of the ménages chase livelihood options that entail incompetent production techniques in aquaculture, fishing, and agriculture.[[ix]] Agriculture, followed by aquaculture, is a cardinal source of subsistence in the Sundarban economy. Around 60% of the overall employed population is contingent on agriculture as a preeminent profession.[[x]]


India positioned third in the Global Climate Risk Index in 2013, a codification of 170 countries that are most exposed to climate change, and the countries influenced most in 2013 were the Philippines, India and Cambodia.[[xi]] Consequential menace is created on the biotic as well as abiotic probity of the deltaic ecosystem by anthropogenic deeds accompanied by climate incongruity. The Indian Sundarban, a “bio‐wall” of the coastal area is currently the most tangible fatality of climate change.

The vital combination of climatic variables encompasses: (i) coastal flooding; (ii) drought; (iii) cyclone; (iv) sea-level rise; (v) SST; (vi) rainfall; and (vii) salinity; which can be illustrated as follows:

1. Air temperature atop the Bay of Bengal is increasing at a rate of 0.019°C per annum. If this upward movement continues, the air temperature in this region is anticipated to leap by 1°C by 2050.[[xii]] The median SST atop the Sundarban delta has risen from 31° to 32.6°C betwixt 1980 and 2007 in the pre‐monsoon stretch, a rise of 0.5°C per decade.[[xiii]]

2. The rainfall of monsoon and post‐monsoon months exhibited a negative shift in the Sundarban delta (–3.84 to –4.42 mm/annum), while pre‐monsoon rainfall manifested a positive shift (+0.98 mm/year).[[xiv]]

3. Cyclone Sidr (November 2007) disintegrated coastal Bangladesh with a remunerative loss of 1.7 billion (U.S. Dollars) and nearly 10,000 lives.[[xv]] In cyclone Aila (May 2009), more than 5 million people were adversely affected in India, and more than 3 million in Bangladesh.[[xvi]] The strike correlated to the Indian Sundarban region was nearly 550 million (U.S. Dollars ) with a loss of over 300 lives, with more than 8,000 persons misplaced.[[xvii]]

4. Correlative sea levels are accelerating in the Sundarban slightly from the eustatic operations, but majorly due to land subsidence effectuated by several natural and anthropogenic operations.[[xviii]]

5. Embankments play a crucial role in the Sundarbans as an arrangement of resistance against cyclonic storms and sea level acceleration, but the structural coherence of numerous embankments are damaged, as they were constructed in the 19th century. The movement of coastal erosion in the Indian Sundarban has been witnessed to be around 5.50 sq. km/annum in the last decade. The overall land region which was 6,402,090 km2 in 2001 has shrunk to 6,358,048 km2 in 2009, recording an average loss of 44,042 km2 land.[[xix]]


In Sundarban, the colonized archipelagos are safeguarded by man‐made embankments opposed to the ingression of saline water. This makes aquaculture and agriculture feasible in the islands.[[xx]] Positive shifts in the incidence of storm surge, cyclone and sea level acceleration are triggering saline water ingression and erosion of landmass in the colonized areas, inducing loss of life, fish crops and agriculture.[[xxi]] In a nutshell, aquaculture is also vulnerable to climate change.

Accordingly, saline water inundation is posing a tremendous menace to aquaculture, particularly freshwater farming via contravention of retardation of growth, decamp of fish stock, mass mortality, pond dykes, entry of other unfavourable species, atrophy of water nature and disease in Sundarban.[[xxii]] In the state of altered affairs, the salination of water and lands in the populated areas of Sundarban may escort more regions under brackish water aquaculture, given the negative viability of freshwater aquaculture and agriculture divisions, thus executing a possibility for this division to maximize on the modifications posed by climate variability.[[xxiii]]


Detrimental impacts of climate fluctuations are putting tremendous stress on the lives and livelihoods of the individuals occupied in fisheries. The extraordinary events like recrudescing floods, cyclones need to be better addressed by amplifying the risk preparedness and adaptive extent of exposed communities. Maturing programs and policies to upgrade the suppleness of natural resources, through estimations of threat and vulnerability, by spreading awareness of climate variability impacts and toughening-up on influential organizations, would assist the institutions adjust to climate incoherence.

In this milieu, acquiring climate‐resilience as an attunement strategy will assist in satisfying the livelihood certainty of the stakeholders linked with fisheries and aquaculture. The selection of genus that are more immune to climatic variability, their procreation and propagation in aquaculture will insure aquaculture production, and sustainable fisheries. Feed‐based policies and other management policies need to be designed to ameliorate the influence of climate fluctuations on fish in order to secure sustainable fisheries and aquaculture production for both livelihood and nutritional certainty.

ENDNOTES [i] Cochrane, K., De Young, C., Soto, D. & Bahri, T, Climate Change Implications for Fisheries and Aquaculture: Overview of Current Scientific Knowledge, Fisheries and Aquaculture Technical Paper No. 530, FAO, Rome (2009). [ii] Cruz, R.V., Harasawa, H., Lal, M., Wu, S., et al., Asia. In: M.L. Parry, Canziani, O.F., Palutikof, J.P., van der Linden, P.J. & Hanson, C.E. (Eds) 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, Cambridge, UK 471–506 (2007). [iii] Csaszar, N.B.M., Seneca, F.O. & van Oppen, M.J.H., Variation in anti‐oxidant gene expression in the scleractinian coral Acropora millepora under laboratory thermal stress, 392Marine Ecology Progress Series93–102 (2009). [iv] Badjeck, M.‐C., Allison, E., Halls, A. & Dulvy, N., Impacts of climate variability and change on fishery‐based livelihoods, 34 Marine Policy 375–383 (2010). [v] Fifth Assessment Report – Climate Change 2014: Synthesis Report, IPCC, Geneva, Switzerland (2014). [vi] Allison, M.A., Khan, S.R., Goodbred, S.L. & Kuehl, S.A., Stratigraphic evolution of the late Holocene Ganges‐Brahmaputra lower delta plain, 155 Sediment Geology 317–342 (2003). [vii] Danda, A.A., Gayathri, S., Gosh, A., Bandyopadhyay, J. & Hazara, S., Indian Sundarbans Delta: A Vision, World Wide Fund for Nature‐India, New Delhi, India (2011). [viii] World Bank (2014), Poverty headcount ratio, http://data.worldbank.org/topic/poverty. [ix] Id. [x] Id. [xi] Kreft, S. & Eckstein, D. (2013), Global Climate Risk Index 2014, http://germanwatch.org/de/download/8551.pdf. [xii] Hazra, S., Samanta, K., Mukhopadhyay, A. & Akhand, A., Temporal change detection (2001–2008) of the Sundarban, Unpublished Report, WWF‐India, New Delhi (2010). [xiii] Mitra, A., Banerjee, K., Sengupta, K. & Gangopadhyay, A., Pulse of climate change in Indian Sundarbans: A myth or reality, 32 National Academy of Science Letters 19–25 (2009). [xiv] Mandal, B., Mukherjee, A. & Banerjee, S., A review on the ichthyofaunal diversity in mangrove based estuary of Sundarbans, 23 Reviews in Fish Biology and Fisheries 365–374 (2013). [xv] Id. [xvi] Id. [xvii] Id. [xviii] Bhattacharjee, A.K., Sufia, Z., Bhattacharyya, S.B., Pramanick, P., Raha, A.K. & Mitra, A., How mangroves respond to hypersaline conditions? Preparedness for predicted sea level rise, 2 International Journal of Scientific Research 360–364 (2013). [xix] Id. [xx] Danda, A.A., Surviving in the Sundarbans: Threats and responses, PhD thesis, University of Twente, Netherlands (2007). [xxi] Chand, B.K., Trivedi, R.K., Dubey, S.K. & Beg, M.M., Aquaculture in changing climate of Sundarban survey report on climate change vulnerabilities, aquaculture practices and coping measures in Sagar and Basanti Blocks of Indian Sundarban, West Bengal University of Animal & Fishery Sciences, Kolkata, India (2012). [xxii] Id. [xxiii] Id.


This blog has been authored by Kavleen Kaur Khurana, who is a 2nd Year B.A., LL.B. student at Maharaja Agrasen Institute of Management Studies, IP University, New Delhi.


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