Madagascar’s once heavily deforested mangrove forests are showing signs of recovery following focused conservation efforts.

Why does this matter? Nearly two-thirds of historic mangrove loss can be attributed to human activity, while half of the world’s mangroves are at risk of collapse, primarily due to human behaviour such as coastal development and shrimp farming.

Forming in intertidal zones, these coastal woodlands are crucial from an ecological perspective as they reduce flood and erosion risk, protect water quality, sequester disproportionate amounts of carbon – drawing in three times the volume of carbon stored by tropical forests of the same size – and house unique biodiversity systems.

Additionally, mangroves provide essential services and economic benefits for coastal communities. The Paulson Institute, a US-based think tank, estimates that restoring degraded mangrove habitats would deliver between $27 billion-$37 billion in annual economic benefits to coastal communities.

Flood damages in a world without mangroves would rise an estimated 16% – roughly equivalent to $82 billion. Research has also revealed the mitigative role mangroves played in protecting coastal communities during the 2004 Indian Ocean tsunami.

The global community is beginning to take action against mangrove degradation. Studies suggest global mangrove loss is slowing as tightening regulation curbs mangrove destruction following its peak in the late 20th century.

Today, more than 42% of the world’s mangroves are protected, and some countries, such as Brazil and Bangladesh, designate over 80% of their mangrove cover with protected status. In Pakistan, mangroves have bucked the global trend and expanded almost three-fold over the last 30 years.

The Mangrove Breakthrough is perhaps the most significant global collective effort to protect these unique environments. Launched at COP27 in 2022, the initiative aims to mobilise $4bn of investment and protect 15 million hectares globally by 2030 via cooperation between national governments, NGOs and financiers.

The Global Mangrove Alliance is another international conservation project, which aims to halt mangrove loss, restore half of mangrove losses since 2018 and double formal protection of mangroves from 40% to 80% globally.

Conservation efforts will be strengthened by industry initiatives, such as the Climate Smart Shrimp nature-based project, led by the non-profit environmental organisation Conservation International.

Increased adoption of nature-based solutions in shrimp farming will be key as the sector grapples with a 10,000% increase in production since 1980, which has led to environmentally degrading high-intensity shrimp aquaculture practices. Conservation International’s initiative aims to couple intensification of shrimp aquaculture with mangrove conservation.

Improved accessibility for companies to seamlessly access and contribute towards mangrove restoration projects is also growing with the launch of platforms, such as Goodcarbon.

The platform leverages a proprietary AI-powered Nature Analytics Framework to design, assess and analyse Nature-based Solution projects based on more than 150 data points, allowing companies to build and manage trustworthy, impactful carbon credit portfolios.

Mangrove restoration is just one project classification of many offered on the platform. Improving connectivity between climate-conscious companies and mangrove restoration project owners will be crucial to continuing the world’s promising progress in reversing decades of mangrove degradation.

Aquaculture conversion of Indonesian mangrove forests has the largest impact on the ecosystems’ carbon sequestration abilities, removing 60% of soil carbon stocks and 85% of biomass carbon, compared to forest harvesting practices which removed most biomass carbon with minimal impacts on soil stocks. The study, published in Global Change Biology, analysed land-use and land-cover change (LULCC) over a 25-year period and compared carbon stocks between undisturbed forest and areas that had undergone LULCC.

Mangroves left to regenerate recovered previous carbon levels after 25 years. LULCC characteristics need to be incorporated in emission-reduction strategies involving mangrove restoration, the authors said.

Mangroves act as nurseries and feeding grounds for many aquatic and terrestrial species and stabilise shorelines against flooding and extreme weather. They are also excellent carbon sinks, particularly within their soils, and have been found to have greater carbon sequestration potential than terrestrial rainforest per hectare.

Mangroves, therefore, represent an excellent nature-based solution for tackling climate change and offsetting emissions.

Carbon sequestration in mangroves involves many uncertainties, such as variability between species or the impact of methane emissions on net carbon stocks, and a limited number of studies have fully considered the different factors involved. This makes it difficult to accurately valorise mangrove restoration initiatives.

This study adds new information regarding the impact of LULCC on blue carbon stocks in mangrove forests; the location of carbon-rich mangroves within blue mangrove forests; the level of carbon losses from different economic activities; and a timeframe for mangrove regeneration. All of this can inform mangrove conservation decision-making.

Corporates should be mindful that offsetting does not fully consider the complex carbon flows within marine ecosystems and the potential for LULCC to erase carbon savings. Mangrove restoration is not a “quick win” but something that requires long-term attention to achieve consolidated results.

Payments-for-ecosystems and carbon resilience payments, whereby coastal communities are incentivised to conserve mangrove forests, may represent a more sustainable form of corporate action, delegating mangrove guardianship to local stakeholders through a multi-factor approach.

Source: Global Change Biology

https://onlinelibrary.wiley.com/doi/full/10.1111/gcb.15056