Increase in soil salinity may lead to decline in yield by 15.6 percent of high-yielding-variety rice and significant changes in the aquatic ecosystems in the Southwest coastal areas of Bangladesh during dry season by 2050, according to recent studies of the World Bank (WB).
The studies said climate change is likely to increase river salinity leading to shortages of drinking water and irrigation. The changes in river salinity and the availability of freshwater will affect the productivity of many capture fisheries.
It will adversely affect the wild habitats of fresh water fish and giant prawn and in addition, salinity increase may induce a shift in the Sunderbans mangrove forest from Sundari (the single most dominant and important species, with the highest market value) to Gewa and Guran, the WB said.
"Estimates from the research indicate that Bagerhat, Barguna, Barisal, Bhola, Khulna, Jhalokati, Pirojpur and Satkhira districts will be most adversely affected," it said.
"The region is already facing problems from salinization and the situation will worsen as climate change continues."
To look more closely at the impacts of climate change on salt water intrusion in the coastal region of Bangladesh, the WB recently conducted five research studies-River Salinity in Coastal Bangladesh in a Changing Climate, Soil Salinity in Coastal Bangladesh in a Changing Climate, the Economics of High-Yield Rice Production in a Changing Climate, Groundwater Salinization and Road Maintenance Costs in a Changing Climate and Livelihood Threats, Family Structure and Economic Welfare in a Changing Climate.
The coastal population in Bangladesh will become more vulnerable to salinity intrusion in a changing climate, it said, adding that the coastal community in southern Bangladesh will be on the "front line" of climate change because of continued sea-level rise (SLR) beyond 2100, even if greenhouse gas emissions are stabilized today.
"Therefore, it is imperative for Bangladesh to understand the potential impacts and begin planning to cope with them," it said.
In the coming decades, the WB said soil salinity will significantly increase in many areas of Barisal, Chittagong and Khulna districts and rice yield will decline by 15.6 percent in nine coastal upazilas where measured soil salinity will exceed 4 decisiemens per meter by 2050.
Without new coping strategies farmers will earn less from HYV rice production in many areas, including losses of 10.5 percent in Barisal and 7.5 in Chittagong, it said, adding that many upazilas have already suffered large yield losses and substantial price reductions from rising salinity, and this will continue as long as the sea-level rise and salinity increases.
It said maintenance expenditure for municipal paved roads in coastal Bangladesh will increase 252 percent because of increased ground water salinity.