Blue Carbon Ecosystems: Climate Change, Vulnerable Communities, and Mangroves in Sri Lanka

As an island nation, Sri Lanka has a long coastline that stretches for 1,340 kilometres. The ecosystems found in the country’s coastal areas, including mangroves, seagrass beds, estuaries, coastal lagoons, and coastal wetlands, are vital for the biodiversity and socio-economic development of Sri Lanka. Not only do they offer a habitat and breeding ground for a multitude of aquatic wildlife, they also play an important role in providing protection from climate risks such as storms and tidal waves and offer a range of ecosystem services.

The carbon stored in coastal and marine ecosystems is called blue carbon. Mangroves, tidal marshes, and seagrass meadows sequester and store blue carbon in both the plants and the soil below, easily surpassing terrestrial forests in carbon per unit area. These ecosystems also provide essential benefits for climate change adaptation, including livelihoods and food security for many coastal communities.

The conservation and restoration of blue carbon ecosystems such as tidal salt marshes, seagrass meadows, and mangrove forests can serve as an effective nature-based solution for climate mitigation and adaptation.

Blue Carbon and Climate Change

Coastal wetlands absorb huge amounts of carbon from the atmosphere as they grow, and the roots of the shrubbery transfer most of this carbon into the rich organic soil below. Unlike terrestrial soils, the soil in which blue carbon ecosystems are found are largely anaerobic (without oxygen). Blue carbon is predominantly stored in waterlogged sediment rather than in biomass, which alleviates risks of sudden carbon loss, particularly from forest fires. Carbon incorporated into the anaerobic soil decomposes at a much slower rate and can be stored for long periods of time, sometimes for thousands of years if it is left undisturbed. Additionally, blue ecosystems can help limit the production of greenhouse gasses (GHG) due to the high salinity found in many blue carbon ecosystems and the fact that their sediments accrete vertically as levels rise. Therefore, they do not become saturated with carbon as terrestrial and freshwater ecosystems do, and the size of the carbon sink and the rate of sequestration continue to increase over time.

Not only do blue carbon ecosystems reduce the amount of GHG found in the atmosphere and the global warming caused by them, they also protect shorelines by preventing coastal erosion, providing storm surge protection, and absorbing incoming wave energy. They have proven to be effective nature-based solutions to mitigate and adapt to climate risks, and in many cases, they are more cost-effective than man-made infrastructure like seawalls and levees due to lower maintenance requirements and natural vertical accretion as sea levels rise. Additionally, they provide other co-benefits which increase biodiversity and support vulnerable communities by providing suitable nursery ground for commercial fish to spawn and naturally purifying sea water.

However, coastal wetlands are being lost at a rate faster than almost any other habitat on Earth, mainly due to anthropogenic activity. The carbon dioxide released from the annual degradation and loss of wetlands is estimated to be equivalent to the annual amount of emissions produced by the United Kingdom. The loss of these blue carbon ecosystems increases the risk of severe flooding and coastal erosion, rendering millions of people in coastal areas increasingly vulnerable to the adverse impacts of climate change.

Mangrove Blue Carbon Ecosystems in Sri Lanka

In Sri Lanka, mangroves can be found along the coastline in estuaries and lagoons. The largest tracts of mangrove habitats in Sri Lanka are found in Puttalam Lagoon, the Kala Oya basin, and Trincomalee. According to Forest Department data, the extent of Sri Lanka’s mangroves is currently estimated at 19,500 hectares of land. Mangroves play a vital role in protecting Sri Lanka’s low-lying coastal zones that are exposed to natural disasters caused and exacerbated by climate change. The loss of Sri Lanka’s mangroves and other blue carbon ecosystems poses a serious threat to vulnerable coastal communities and coastal biodiversity. The loss of mangroves in Sri Lanka over the last few decades has been mainly caused by enterprises like shrimp farms, salt pans, and poorly planned construction.

Sri Lanka’s coastlines are also impacted by the influx of tourism, illegal, unreported, and unregulated (IUU) fishing and fish farming, and the development of unsustainable economic activities such as aquaculture. To restore these coastal wetlands, viable economic alternatives for the vulnerable communities affected by the abandonment of these activities are required. 

Mangrove ecosystems serve as globally significant carbon sinks. Almost 15% of the total carbon deposited in coastal sediments in tropical and sub-tropical coastal areas is accounted for by the sequestration of organic carbon in the standing biomass of mangroves, its root biomass, and mangrove soils. They are a prime example of how nature can be used to enhance climate change mitigation strategies and, therefore, offer opportunities for countries to achieve their emissions reduction targets and Nationally Determined Contributions (NDCs) under the Paris Agreement.

Mangrove Ecosystems Conservation and Restoration in Sri Lanka

In Sri Lanka, several laws have been implemented to protect the country’s mangroves. The following Acts and Ordinances are relevant to mangrove conservation: the Forest Ordinance No. 16 of 1907, the Fauna and Flora Protection Ordinance No. 2 of 1937, the National Environmental Act No. 47 of 1980, the Coastal Conservation Act No. 57 of 1981, the Fisheries and Aquatic Resources Act No. 2 of 1996, the Marine Pollution Prevention Act No. 35 of 2008, and the Conservation of Fish and Aquatic Resources within Sri Lankan Waters Regulations 2016.

In addition, Sri Lanka has a number of policies, plans, and strategies that relate to the conservation and restoration of mangroves, including the National Forest Policy of 1995, the National Biodiversity Strategy and Action Plan of 1999, the National Wildlife Policy of 2000, the National Environmental Policy of 2003, the National Policy on Wetlands of 2006, the National Fisheries Policy of 2006, the National Policy on Climate Change of 2012, and the National Adaptation Plan for Climate Change Impact in Sri Lanka 2016.

Sri Lanka has illegalised the cutting down of all mangroves island-wide, and is recognised as a leader in the conservation of mangroves among Commonwealth countries. There are several designated sanctuaries that contain mangroves, such as Chundikulam lagoon and Kokkilai lagoon. In order to further enhance the protection given to vulnerable mangrove ecosystems, it would be beneficial to declare marine protected areas in mangrove-rich areas along Sri Lanka’s coastline.

In January 2020, Sri Lanka’s Cabinet of Ministers approved the National Policy on Conservation and Sustainable Utilization of Mangrove Ecosystems in Sri Lanka, which was developed by the National Expert Committee on Mangrove Conservation and Sustainable Use. Furthermore, Sri Lanka is party to several relevant international agreements including the Ramsar Convention, the Paris Agreement, the Convention on Biological Diversity, the 2030 Agenda for Sustainable Development, and the Aichi Biodiversity Targets. The country’s National Adaptation Plan also contributes to mitigating climate risk and adapting to climate change impacts, with both the coastal and marine sector and the biodiversity sector containing provisions related to mangroves.

Non-profit organisations, alongside the government and the private sector, have shown an interest in maintaining mangrove restoration and conservation through activities like the Blue-Green Protectors Programme. SLYCAN Trust, in collaboration with government entities such as the Marine Environmental Protection Authority and the Coast Conservation Department has undertaken projects to protect mangrove areas found in Kaputhoo lagoon (Jaffna district), Kalpitiya (Puttalam district), Dikkowita (Negombo district), and Mannar (Mannar district), focusing on livelihood development, mangrove-based ecotourism development, and waste management.

Several community-led rehabilitation projects have been undertaken by different organisations and private entities, for example the Sri Lanka Mangrove Conservation project started in 2015 with government involvement and the aim to replant 4,000 hectares of mangroves. As a country, Sri Lanka has now committed itself to restore another 10,000 hectares of mangroves by 2030, an ambitious target that has the potential to greatly benefit coastal communities, wildlife, and climate change adaptation and mitigation.

The Way Forward

It is important to acknowledge that these coastal ecosystems are sensitive to sea level rise, increases in ocean temperatures, heightened frequency and intensity of storms, and changes in precipitation patterns. In addition, climate change is intensifying the rise in atmospheric concentrations of carbon dioxide, thus causing the oceans to absorb more carbon dioxide and become more acidic. This has exacerbated adverse impacts such as shoreline erosion and coastal flooding on marine and coastal ecosystems. To mitigate and adapt to climate change, protect vulnerable coastal communities, and stop the degradation of coastal and marine ecosystems, supporting and investing in the nature-based development of blue carbon ecosystems is crucial.

Even though there is sufficient protection afforded by Sri Lanka’s legislature to conserve mangroves, the destruction or degradation of mangrove forests through commercial and industrial activities, infrastructure, and human settlements continues. Furthermore, anthropogenic activities like pollution and unsustainable extraction of resources from mangrove forests threaten to aggravate the problem.

Supporting vulnerable communities and stopping the degradation of mangroves can both be addressed through the adoption of community-based mangrove restoration projects, multi-stakeholder partnerships including government authorities, and sustainable livelihood development, for example in ecotourism. Not only will this contribute to the improvement of carbon sequestration and storage, coastal protection, fisheries, and climate resilience, it can provide new income sources for vulnerable coastal communities and improve their livelihoods. Furthermore, promoting government-led initiatives to allocate greater budgets to protect mangroves and other blue carbon ecosystems and enforcing marine protected area regulations can contribute significantly to averting the impacts of climate change on vulnerable communities in coastal areas.

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