As the world struggles to tackle climate change and build resilience to prepare communities for its devastating impacts, nature-based solutions are presented as a panacea. These projects, which use nature and natural processes to help alleviate the impacts of climate change and harmful human activities, are increasing in number and size.
In the Philippines and India, mangrove forests are being expanded in conjunction with existing breakwaters along the coasts to protect against storms and flooding. Similarly, in South Africa, wetlands are being restored to replenish groundwater and protect against drought in water-insecure cities, such as Cape Town.
Communities worldwide are being encouraged to scale up nature-based solutions and integrate them into modern infrastructure. A 2021 report published by the International Institute for Sustainable Development (IISD) concluded that such an approach could save the world $248 billion annually in building costs for expanding infrastructure.
Governments around the world are investing in research and development of nature-based solutions, while global financial institutions such as the World Bank are actively involved in funding projects that use such approaches.
As urban planners studying water, urbanization and climate justice in small and medium-sized South Asian cities, we agree that nature-based solutions hold promise. But we also recommend caution. Our work in Khulna, a region of southern Bangladesh facing multiple ecological crises, is an example of how integrating nature-based solutions can lead to complex outcomes that help some communities and harm others.
Khulna’s ‘nature-based solution’
In 2011, Khulna, Bangladesh’s third largest city, was experiencing severe water scarcity. Along with declining groundwater and pollution, there has been increasing salt water intrusion into the freshwater resources. The local government had several options to deal with the crisis.
It could build a desalination plant to purify water from nearby rivers. But such installations are known to be environmentally harmful. For example, a paper by the Canada-based Institute for Water, Environment, and Health notes that desalination plants worldwide discharge 142 million cubic meters of hypersaline brine every day. That’s enough to cover the US state of Florida under 12 inches (30 cm) of brine, which can be toxic and incredibly harmful to marine life.
Another option the local government had was to introduce stricter water controls for residents and businesses. This would include asking residents to conserve water and asking industries to abandon water-intensive practices and invest in stormwater harvesting systems. Such water conservation policies can be difficult to implement and politically unpopular.
To avoid the negative effects of a desalination plant and potentially unpopular water conservation policies, the local government opted to build a “climate resilient” water supply system for which it secured foreign funding from the Asian Development Bank and the Japanese International Cooperation Agency (JICA).
This water supply system was intended to collect water from the Madhumati River in the village of Mollahat, 40 km northeast of Khulna, and bring it to the city. During the rainy season, the water would be processed directly by a water treatment plant and then supplied to consumers. During the dry season, when the salinity of the Madhumati is high, the water would be mixed with low-salt water collected in a reservoir during the rainy season to lower the salt concentration before sending it to the plant.
Policymakers hoped that this “nature-based solution” of water mixing would address future problems as rising seas will continue to increase salinity in Khulna’s waters. By framing the new water infrastructure in a climate- and nature-friendly way, the local government was able to justify the construction of the expensive project.
The new water infrastructure, which was completed in 2019, indeed benefited the residents of Khulna. It increased access to piped water from 23 percent of households to 65 percent and provided access to water to some informal settlements that were not previously there.
The problem that created the ‘solution’
The popularity of the new water system in Khulna was evident from the interviews we conducted with the residents of the city. They reported that women could now get water from the tap at set times instead of standing in line for hours to get water from wells.
However, Mollahat’s reports were completely different. During our fieldwork in 2018, one of us spoke to a local resident, Mohammad Liton, who said he had barely slept that year. Liton was overcome with concerns about rising salinity and low water levels in the Madhumati River, which had begun to affect his livelihood. Liton argued that the Khulna water project had reduced the availability of water for fishing and rice cultivation in the Mollahat area.
In January 2017, Liton and other residents of Mollahat protested against the project, which affected the lives of thousands of farmers and fishermen living in the village, but authorities did not address their concerns.
The environmental impact assessment of the project, which was required by the government of Bangladesh and the foreign donors and completed in 2011, focused closely on the water site and listed the construction as having the only impact on Mollahat.
According to Bangladesh Environmental Lawyers Association (BELA) representatives whom we interviewed, the scale of the assessment erroneously stated that the Madhumati River basin exists only in Bangladesh. The river is a tributary in the complex Ganges river system, with streams emanating from the Ganges in neighboring India.
The Madhumati River has been hit hard by the upstream construction of the controversial Farakka Dam in the Indian state of West Bengal, which diverts the water. The dam has made the river basin much more sensitive in time and ecology and so the added burden of drawing water for the Khulna project has significantly strained river resources and affected Mollahat and other communities along the basin.
Be careful with nature-based solutions
Khulna’s water project should be a cautionary tale – one that can teach policymakers lessons about dos and don’ts when implementing nature-based solutions.
In this case, the industries and households of Khulna reaped the benefits of the projects, while the residents of Mollahat bore the costs. This could have been avoided if the local authorities had consulted the villagers on the construction site and downstream when evaluating the impact of the project. Their feedback could have been used to adjust the performance.
Local authorities should also have aimed to distribute the benefits equally between the population of the city and nearby rural communities. For example, they could have asked industries to conserve water, which would have reduced the pressure on the Madhumati River and greatly reduced the impact on the Mollahat community.
When green approaches are combined with infrastructure, local authorities must ensure that no harm is done to neighboring communities. Solving a city’s water problem should not come at the cost of devastating rural communities.
As nature-based solutions scale up, we urge policymakers, donors and communities to be more cautious. Infrastructure projects, such as the one in Khulna, should minimize harmful impacts and help address disparities at the local level and between regions.
The views expressed in this article are those of the authors and do not necessarily reflect the editorial view of Al Jazeera.