Addressing Climate Change Vulnerability of Coastal Cities Through Mangrove Forests

Around the world, coastal cities are threatened by storms, rising sea levels, and other climate change related hazards. With conventional approaches often both costly and ineffective, nature-based solutions are offering valuable alternatives. One example are the community-based methods developed by the NGO Mangrove Action Project.

The Loss of Coastal Cities?

The climate crisis is real and measurable. Sea levels are rising, storms and droughts are intensifying at an alarming rate. A recent study warns that major coastal cities such as Mumbai, Shanghai, Jakarta, and Bangkok could be lost to rising sea levels over the next 30 years, affecting an estimated 300 million people living along the world’s coasts. This is about three times the number of people affected than previously estimated.

“The figure could double to 630 million people affected by 2100 if little is done to rein in greenhouse gas emissions. These assessments show the potential of climate change to reshape cities, economies, coastlines and entire global regions within our lifetimes,” says Scott Kulp, lead author of the study.

Earlier projections seem to have been far too conservative, while newer ones claim that major coastal population centres run risks of becoming completely inundated, displacing hundreds of millions of people, resulting in tragic environmental, social and economic disruption. For instance, much of Southern Vietnam will be inundated, where rising seas would potentially displace a quarter of the country’s population. The cities of Mumbai and Bangkok could be completely submerged.

Adaptation Potential

We still can avoid the full extent of these dire predictions if we take effective steps now to mitigate the impending disaster and take actions to adapt. Conventional measures such as building effective sea walls and other man-made barriers can help – but can also be quite costly, as the case of Jakarta shows.

Indonesia’s capital, which is severely affected by sea-level rise and land subsidence, is taking herculean measures to counter the city’s submergence by constructing a 25 kilometre long sea wall to hold back the incoming tides. The development is one of the world’s largest infrastructure projects, costing an estimated 40 billion US dollars. And yet, it is questionable for how long such countermeasures will be effective.

The Power of Mangroves

The Mangrove Action Project (MAP) recommends a different, more natural, environmentally sound, long-term approach that utilises the mangrove wetlands as a natural barrier to climate change and rising sea levels.

Mangrove forests are vital for healthy coastal ecosystems in the tropics and sub-tropics. These forest wetlands support an array of marine and coastal life, serving as fish nurseries, nesting and feeding grounds for migratory birds, and last stands for Bengal tigers and lemurs and a wide variety of other fauna.

Mangroves have most recently been recognised for their important role in reducing climate change. They are capable of sequestering up to five times more carbon than other forest ecosystems, storing that carbon in their peat soils for hundreds, if not thousands of years. In addition, mangroves play a life-supporting role for coastal urban communities who depend on mangroves for protective buffers against storms, erosion and sea level rise.

Yet, mangroves are one of the most threatened habitats on earth, with an annual loss outpacing other tropical rainforests. It is estimated that less than 15 million hectares remain worldwide, less than half their original area. Their disappearance is primarily due to clearing for aquaculture, timber and fuelwood extraction, charcoal production, urbanisation, industrial and agriculture expansion, pollution, road construction, and other infrastructure developments. More than ever before, it is imperative to counter these losses. This is one of the challenges taken up by MAP since its founding in 1992.

Community-Based Ecological Mangrove Restoration

Traditional mangrove restoration efforts face a number of challenges in restoring healthy mangrove ecosystems. Most are erroneous attempts to establish monoculture plantations that lack biodiversity and true ecosystem function, or project designs that neglect underlying problems or stressors that impact mangroves and cause their loss in the first place, such as unusually high salinity or disturbed hydrology – tidal flow and mixing of salt and fresh water – essential to healthy mangrove ecosystems.

To counter the high rates of failed mangrove rehabilitation attempts, MAP has developed a set of “best practices” via its Community-Based Ecological Mangrove Restoration. CBEMR works to restore underlying hydrology and considers adjustments to a disturbed area’s topography. It ensures that mangroves may regenerate naturally, resulting in true ecosystem restoration with a richer biodiversity.

Through CBEMR, MAP builds on traditional community ties to mangroves: community engagement and empowerment that ensure full participation of local communities affected by climate change is critical to successful, sustainable long-term mangrove conservation and restoration efforts.

To involve communities from the start of the project, it’s important to learn about past and present conditions of proposed mangrove sites as well as about the local community’s relationship to the site.

Initially, local community members who are interested in acting as future monitors and resource managers at selected sites are introduced to the CBEMR approach. Once the community is engaged, local conservation groups develop community management plans critical to the process, thus preventing repeated degradation of the restoration site.

Strong community stewardship ensures a central stakeholder role in future mangrove management decision-making. A five- to eight-year-long monitoring and evaluation process of the restored sites through community members is built into the CBEMR to ensure long-term success. Once the management plan is developed, mangrove restoration can move forward in parallel.

MAP offers intensive training workshops, lasting between three and twelve days, that instill the basic principles of CBEMR and also include hands-on fieldwork at actual restoration sites. Each workshop is geared towards the local conditions, involving local mangrove ecologists, officials, local communities, and associated NGOs in the process. Once communities are trained, MAP offers guidance and technical support to ensure success of restoration.

In 2020, MAP plans to scale up its global operations, conducting further CBEMR capacity-building workshops in Asia, Africa, and the Americas. Thus, MAP continues to support the restoration of a naturally functioning habitat through the CBEMR ecosystem approach. CBEMR fosters a restoration approach that aims to create a more long-term, biodiverse, resilient ecosystem that is better suited to face the exigencies of the climate crisis than traditional monoculture approaches, making it a “best practices” method for restoring mangrove wetland ecosystems.