Increased soil salinity due to climate change-induced rises in sea-levels is likely to force nearly 2 lakh coastal residents to migrate to inland areas within Bangladesh to find alternate livelihoods, according to a study.
Researchers at the International Food Policy Research Institute (IFPRI) and the Ohio State University conducted the study, “Coastal Climate Change, Soil Salinity, and Human Migration in Bangladesh”.
The study examines, for the first time, the complex relationship between flooding, soil salinity, rural livelihoods and migration; as well as the probable adaptation strategies, said a press release on Tuesday.
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.
According to the study, 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 alternate districts.
It shows only a few are likely to migrate to northern areas, while most migrants are likely to enter the capital city of Dhaka, and onward to neighbouring districts in the coastal region.
The study co-authored by IFPRI’s Valerie Mueller (also Assistant Professor, Arizona State University); and Ohio State University’s Joyce Chen, 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.
Increased salinity adversely impacts crop production and income, driving those who rely on it for their livelihood to migrate from coastal to inland areas.
The study finds increasing soil salinity from the lowest to the highest levels observed in the data would likely increase internal migration by nearly 25 percent, while decreasing international migration by 66 percent. 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, signaling a trapped population dynamic, raising concerns that the most vulnerable households may be the least resilient in the face of climate change,” adds Chen.
Due to rise in soil salinity, Chittagong and Khulna districts are likely to witness 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 like Bagerhat, Bhola and Feni generally will 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 labor is relatively unaffected by salinity. However, higher wages and denser labor 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 rise in the long-run, the study says.
Studies show that in another 120 years, coastal areas, currently home to 1.3 billion people, are projected to be inundated by sea level rise. “A two-pronged approach will be necessary to address this growing concern,” Mueller points out.
Researchers point out that infrastructure projects such as embankments and polders may have more limited success; saline contamination increases pressure to increase aquaculture which, in turn, increases the demand for brackish water, making households reluctant to maintain such infrastructure.