Blue Carbon as an Effective Natural Climate Solution: A Brazilian Case Study
Climate change and coastal ecosystems
A quick glance at the news shows that coastal and marine ecosystems are on the front lines of climate change. In California, rising sea levels have led to coastal erosion, increased flooding, and saltwater intrusion. In Mozambique and Malawi, powerful tropical cyclones have ravaged coastal communities in recent months. However, these coastal and marine ecosystems can also be part of the solution.
Natural climate solutions – actions that use the environment to increase carbon storage and reduce greenhouse gas emissions in forests, grasslands, and wetlands across the globe – play an essential role in helping the world effectively address the climate crisis. A recent study found that natural climate solutions can provide 30-37% of the emissions mitigation needed to stabilize the planet by 2030 (Griscom et al., 2017). Mangroves, seagrasses, and tidal marshes — collectively known as blue carbon ecosystems — can store large amounts of carbon in their soils and sediments (Hilmi et al., 2021). They also provide other ecosystem services, including serving as essential biodiversity hotspots, providing a source of food and income, and protecting coastal communities from flooding and erosion.
“Natural climate solutions can provide 30-37% of the emissions mitigation needed to stabilize the planet by 2030.”
What are mangrove forests, and why are they important?
Mangrove forests are a type of coastal wetland ecosystem. Carbon is stored in mangrove forests through two main pathways: first, in woody biomass, and second, in soils. Compared to terrestrial forests, mangrove forests store more carbon underground, meaning that they are more resilient to disturbances and less likely to release carbon dioxide once it is stored.
Despite their importance in the fight against climate change, mangrove forests are still susceptible to natural and anthropogenic damage. In the 1970s and 1980s, much of the world’s mangrove forests were significantly degraded or destroyed, predominantly due to the rise of industrial shrimp farming. Since the early 2000s, the rate of loss has declined, in part due to the concerted effort of governments, conservation organizations, and other stakeholders who have implemented policies and programs to protect these essential ecosystems. However, mangrove forests still face many threats today.
Case study: mangrove forests in Brazil
Almost every coastal state in Brazil has mangroves – from the northernmost state of Amapa down to the southern state of Santa Catarina. Brazil is home to the second-largest mangrove area in the world, but historically, a weak regulatory environment and competing interests have made mangrove conservation and restoration difficult. Moreover, Brazil – like many other coastal countries around the world – does not have an accurate inventory of its mangrove forests and their carbon sequestration potential (Rovai et al., 2022). Without up-to-date inventories, it is difficult for the Brazilian government and the country’s private sector to access the information needed to develop policies and strategies to conserve, protect, and effectively use mangroves as a climate change mitigation and adaptation tool.
Current challenges
There are several barriers to the effective management and protection of mangrove ecosystems in Brazil. First, during some administrations, there has been a lack of political will to protect these ecosystems, meaning that most of the efforts to restore and conserve mangrove forests have had to take place at a local level. Second, there is not enough information about the extent of Brazil’s mangrove forests or quantifiable data on their ability to sequester carbon long term. This is particularly the case as it relates to the Amazon Macrotidal Mangrove Coast (AMMC) – the largest continuous area of mangrove forests in the world (Tomaz et al., 2019). The AMMC is particularly vulnerable to sea-level rise, adding a level of complexity to current attempts to calculate the region’s carbon sequestration potential.
Finally, it can be difficult to quantify the value of a natural resource as extensive, varied, and heterogeneous as mangroves, which have characteristics of both terrestrial and marine ecosystems. Traditional economic valuation is anthropocentric and focuses on a resource from the perspective of its use to humans. However, resources can also have other benefits, including non-use benefits. Practically speaking, being able to determine a value for the benefits mangrove forests provide would help governments and policymakers make smarter decisions that account for these ecosystems’ role in the economy. From a private sector perspective, valuing mangrove forests could help businesses manage risks in their supply chains and make their operations more sustainable.
Looking ahead: the future of mangrove forests in Brazil
To protect Brazil’s mangrove forests and achieve adequate government buy-in, it will be important to frame the conservation of these ecosystems in terms of the economic benefits they provide. For example, mangrove forests bring the Brazilian government revenue from tourism, and they are also home to some of the country’s most productive fisheries. Policymakers are typically more amenable to investment in protecting critical ecosystems when they understand the monetary benefits these ecosystems provide. A recent global study found that the benefits of mangrove restoration and conservation could outweigh the costs by 3:1 (Northrop et al., 2020). Therefore, communicating that protecting mangrove forests is cost-effective and a smart political and business strategy can go a long way.
Another financial mechanism would be to consider promoting blue carbon credits. Many businesses in Brazil and around the world have made bold commitments to achieve net-zero emissions. Carbon credits can play an important role in achieving this goal. However, to be successful, carbon credits need to be promoted in conjunction with significant emissions reductions. Moreover, in order for carbon credit programs to work, there needs to be meaningful community engagement. For example, working closely with communities to ensure that the types of mangroves planted are suitable for the local context and can provide people with the resources they need to survive. One method that seems to be working well in Tanzania and could potentially be scaled to other regions is called community-based ecological mangrove restoration (CBEMR). This model addresses the root causes of mangrove forest degradation and works with local communities to address political, social, and environmental barriers to conservation (Johnston, 2021).
In Brazil and around the world, mangrove forests play an important role – both in terms of carbon sequestration benefits and in terms of other ecosystem services, such as erosion control, habitats for marine life, and sources of livelihoods for coastal communities. However, these ecosystems are under threat. Several economic and financial policy levers could help the situation, particularly in the Brazilian context. First, being able to quantify the economic benefits mangrove forests provide would help policymakers develop legislation that accurately reflects the importance of these ecosystems to the overall functioning of Brazilian society. Second, promoting the more widespread use of blue carbon credits could help businesses reach their net zero emissions targets in a way that is also directly benefiting marine ecosystems.
References
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