Rise in sea level has brought about increased soil salinity that is likely to force nearly 200,000 coastal residents to migrate inland in search of alternative livelihoods, according to a landmark study by researchers at the International Food Policy Research Institute (IFPRI) and the Ohio State University. The study examines, for the first time, the complex relationship between flooding, soil salinity, rural livelihoods and migration. It also suggests probable adaptation strategies.
“Many parts of Bangladesh are under severe threat of future sea-level submergence, but studies show the migratory response to flooding is likely to be minimal as most farmers have already adapted their cultivation practices to cope with changes in the frequency and intensity of flooding in this deltaic region. However, our study shows increased soil salinity from rising seas will push nearly 140,000 coastal residents to migrate to another location within their district, and nearly 60,000 would move to alternative districts,” says Valerie Mueller, senior research fellow, IFPRI.
The study shows that only a few are likely to migrate to northern areas, while most migrants are likely to enter Dhaka and neighbouring districts in the coastal region.
The study titled ‘Coastal Climate Change, Soil Salinity, and Human Migration in Bangladesh’ is co-authored by IFPRI’s Valerie Mueller and Ohio State University’s Joyce Chen. It will be published in an upcoming edition of the journal ‘Nature Climate Change’.
The study draws on socio-economic data from the country’s Bureau of Statistics’ Sample Vital Registration System and agricultural production data from Household Income and Expenditure Surveys, covering nearly half a million coastal households in a year.
The recent report of the United Nation Intergovernmental Panel on Climate Change (IPCC) lays bare that a country like Bangladesh is particularly vulnerable to climate change and is likely to lose economically.
Given this, people of such countries will need to adopt coping strategies to deal with climate change-induced accelerating sea-level rise, leading to increased inundation and saline contamination of soils. Increased salinity adversely impacts crop production
and income, driving those who rely on it for their livelihood to migrate from coastal to inland areas. To offset the loss from crop production income, households move to aquaculture. Findings from the study reveal that households already engaged in both crop production and aquaculture heavily rely on the latter to buffer adverse environmental conditions.
“As soil salinity increases from low to high salinity levels, we see a nearly 57 per cent increase in the share of revenue from aquaculture,” says Mueller.
For most households, however, the prohibitive costs associated with converting crop land into fish ponds deter additional diversification.
Increased aquaculture production in the coast, the study points out, brings more job opportunities and reduces international migration. “So, people who would normally migrate abroad might be staying to take jobs that were made available by aquaculture production. Also, poorer households affected by the changes may have less money available for more expensive international migration,” says Chen.
The study finds that the increasing soil salinity from the lowest to the highest levels is likely to increase internal migration by nearly 25 per cent. It is likely to decrease international migration by 66 per cent. The number of migrants who move to a different location within the district is more than double of those who move out of the district.
“Financial constraints limit poor households from moving over longer distances, signalling a trapped population dynamic, raising concerns that the most vulnerable households may be the least resilient in the face of climate change,” says Chen.
Only those with greater financial, human or social capital may take the giant step to move internationally, the study observes.
Owing to a rise in soil salinity, Chattogram and Khulna districts are likely to witness the highest within-district additional migration—estimated between 15,000 and 30,000 migrants per year. These two districts also contain the second and third largest cities in the country. Districts without large cities, such as Bagerhat, Bhola and Feni, will generally expect smaller within-district flows—between 5000 and 15,000—but larger out-of-district flows, particularly to districts with large cities.
“To minimise moving costs and remain close to family, individuals may move inland where the demand for agricultural labour is relatively unaffected by salinity. However, higher wages and denser labour markets may draw workers instead to urban areas,” says Mueller. With three of the country’s five largest cities in the saline belt, migration may not reduce vulnerability to sea level rises in the long-run.
According to the study, soil salinity reduces the total annual crop revenue: households facing moderate saline contamination earn almost Tk. 5,000, or 21 per cent less in crop revenue each year, compared to households facing only mild soil salinity.
The researchers did not find any significant effect of flooding on the crop revenue.
Studies show that in another 120 years, coastal areas, currently home to 1.3 billion people, are projected to be inundated by sea level rises. “A two-pronged approach will be necessary to address this growing concern,” Mueller points out.
“First, government efforts to incentivise individuals that live in these key vulnerable areas to relocate may be necessary, especially to detract movement away from population-dense areas like Chattogram and Khulna. A study in the Brazilian Amazon suggests that compensation-based resettlement programmes can be welfare-enhancing in the short term,” he notes.
“Second, policymakers may adopt more forward-looking development strategies to take advantage of the surplus labour provided by the coastal areas to promote modern economic activities, like manufacturing, in less populated areas,” he adds.
Expanding the demand for labour in modern industries located in secondary towns can sustain job growth as more and more migrants reach these targeted locations.
The researchers point out that infrastructure projects, such as embankments and polders, may have more limited success. Also, saline contamination increases pressure to increase aquaculture which, in turn, increases the demand for brackish water, making households reluctant to maintain such infrastructure.
The International Food Policy Research Institute (IFPRI) seeks sustainable solutions for ending hunger and poverty. The IFPRI was established in 1975 to identify and analyse alternative national and international strategies and policies for meeting the food needs of the developing world. To this end, it puts particular emphasis on low-income countries and on the poorer groups in those countries.
This report was originally published in The Independent on 24 October 2018.