Mangroves are being destroyed at a rate 3-5 times greater than the average rates of forest loss, costing billions in economic damages and denying millions of people the ecosystem services they need to survive, according to a new report by the United Nations Environment Programme (UNEP).
Found in 123 countries and covering 152,000 sq-km, over 10 crore people around the world live within 10 kilometres of large mangrove forests, benefiting from a variety of goods and services such as fisheries and forest products, clean water and protection against erosion and extreme weather events.
The study describes how emissions resulting from mangrove losses make up nearly one-fifth of global emissions from deforestation, resulting in economic damages of some $6-42bn annually.
Mangroves are also threatened by climate change, which could result in the loss of a further 10-15% of mangroves by 2100.
The report titled “The Importance of Mangroves: A Call to Action” was launched on September 29 at the 16th Global Meeting of the Regional Seas Conventions and Action Plans in Athens, Greece.
The report argues that in spite of the mounting evidence in support of the multitude of benefits derived from mangroves, they remain one of the most threatened ecosystems on the planet.
It describes financial mechanisms and incentives to stimulate mangrove conservation, such as REDD+, private sector investments, and the creation of Nationally Appropriate Mitigation Actions for developing countries to reduce greenhouse gas emissions while increasing national capacity.
The mangrove forest of Bangladesh's Sundarbans part in the southern coastal area – declared as Unesco World Heritage Site – has also been exposed to newer threats as hazardous shipbreaking yards, coal-fired power plants and other heavy industries are allowed around the forest in a mindless manner. Moreover, plying of water vessels on the forest's rivers and canals have been increasing with smugglers chopping off trees regularly.
UN Under-Secretary-General and UNEP Executive Director Achim Steiner said: "Mangroves provide ecosystem services worth around $33-57,000 per hectare per year. Add to that their superior ability to store carbon that would otherwise be released into the atmosphere and it becomes clear that their continued destruction makes neither ecological nor economic sense.
"Yet, the escalating destruction and degradation of mangroves – driven by land conversion for aquaculture and agriculture, coastal development, and pollution – is occurring at an alarming rate, with over a quarter of the earth's original mangrove cover now lost. This has potentially devastating effects on biodiversity, food security and the livelihoods of some of the most marginalised coastal communities in developing countries where more than 90% of the world's mangroves are found."
By quantifying in economic terms the value of the ecosystem services provided by mangroves as well as the critical role they play in global climate regulation, the report aims to encourage policymakers to use the tools and guidelines outlined to better ensure the conservation and sustainable management of mangroves, he added.
Mangrove degradation and loss is predicted to continue into the future if a business-as-usual scenario prevails.
The UNEP report offers readers and especially policymakers many management and protection measures and tools that are available for use at national, regional and global scales to help ensure a sustainable future for mangroves.
Policymakers, it says, should consider several of these, including integrating mangrove-specific goals and targets into the post-2015 UN Sustainable Development Goals agenda, as well as better coordination of global action on mangroves through the development of a Global Mangrove Commission, and the streamlining and coordination of Multilateral Environmental Agreements.
Protecting these long-term reservoirs of carbon, and preventing their emissions from being released back into the atmosphere is, the report says, a sensible and cost-effective measure that can be taken to help mitigate climate change.
Key Findings:
Ecosystem Services
* By 2050, South-East Asia will potentially have lost 35% of the mangrove cover it had in 2000, with associated negative ecological and socio-economic impacts.
* Ecosystem service losses in South-East Asia from the destruction of mangroves has been estimated at more than US$2 billion a year over the period 2000 – 2050, with Indonesia predicted to suffer the highest losses at $1.7bn per year.
Climate Change Regulation and Mitigation
* Research is increasingly pointing to the role of mangroves as significant carbon storage systems, sequestering vast amounts of carbon – about 1,000 tonnes per hectare – over thousands of years, making them some of the most carbon-rich ecosystems on the planet.
* One study carried out in the Potengi Estuary in Brazil on 1,488 hectares of mangroves found that the forest trees and sediments were retaining concentrations of heavy metals that would otherwise cost $13m to treat in a zeolite plant.
Livelihoods
* A large number of commercially important fish species such as snapper, mullet, wrasse, parrotfish, sharks and rays utilise mangroves during all or part of their lives, with the mangrove providing critical food, shelter and refuge functions.
* It has been estimated that 30% of the fish caught in South-East Asia are supported in some way by mangrove forests; a figure approaching 100% for highly mangrove-dependent species including some species of prawn.
* It was estimated that the annual average landing of mangrove-associated fish and blue crab in the Gulf is 10,500 tonnes, with an estimated total value of $19m to local fisheries.
Extreme Weather Events
* The complex network of mangrove roots can help reduce wave energy, limit erosion and shield coastal communities from the destructive forces of tropical storms, cyclones and tsunamis.
* The mangrove-lined “hurricane holes” in the Caribbean have been a well-known safe haven for vessels for centuries, and of the 20-odd established hurricane holes recommended for boaters needing to ride out storms in the Antilles, 16 gain such a reputation because of the presence of mangroves.
* In Vietnam, extensive planting of mangrove has cost of $1.1m but has helped reduce maintenance cost of the sea-dyke by $7.3m per year.
Biodiversity Hotspots
* Mangroves form the foundation of a highly productive and biologically rich ecosystem that is home to a spectacular range of species of birds, mammals, invertebrates and fish which help to support people through fisheries, tourism and cultural heritage.
* The combination of clearance and degradation has meant that globally about 16% of mangrove tree species and some 40% of the animal species dependent on these ecosystems are now considered vulnerable and/or at risk of extinction. The mangroves of Australia are home to over 200 species of birds, and at least 600 different fish species are known to occur in mangroves across the Indo-Pacific region.
Recommendations:
Policymaker guidelines for the improvement, management and protection of mangroves include the development of protocols to Regional Seas Conventions that promote protection and sustainable use of mangroves, and the implementation and enforcement of national laws and policies relevant to mangrove protection and management. Others include:
* Create a Global Mangrove Fund to support “climate resilience” actions that conserve and restore mangroves, and protect the carbon stored within them;
* Encourage mangrove conservation and restoration through carbon credit markets such as REDD+, the “Bio-Rights” mechanism and corporate and private sector investments;
* Promote economic incentives such as Payments for Ecosystem Services as a source of local income from mangrove protection, sustainable use and restoration activities and ensure beneficiaries of mangrove services can find opportunities to invest in mangrove management and restoration planning;
* Explore opportunities for investment into Net Positive Impact biodiversity offsets by the corporate and business sectors as a way to finance the protection and sustainable use of mangroves;
* Ensure that mangroves are addressed in wider Marine Spatial Planning and policy frameworks.