Last September, Belize made the bold decision to include nature-based solutions such as safeguarding coastal wetlands within its updated nationally determined contribution (NDC) to the Paris Agreement, an international treaty on climate change. By committing to protect and restore both mangrove and seagrass ecosystems, the country recognized the benefits that these ecosystems offer: buffering coastal communities against the full impact of storms and flooding; providing wildlife with critical nursery and foraging grounds; and removing carbon dioxide from the environment and storing this carbon in their soils. If undisturbed, this carbon can remain in place—and out of the atmosphere—for millennia.
A research project last September—led by the Smithsonian Institution in partnership with the University of Belize, World Wildlife Fund, and supported by The Pew Charitable Trusts—brought together government departments, local NGOs, and international researchers to take soil cores and tree measurements to estimate the amount of carbon stored in Belize’s mangroves. The findings of this first-time comprehensive study will help the country’s decision-makers determine the next steps to implementing the commitments in Belize’s NDC.
To highlight World Wetlands Day, two scientists explained their role in the carbon stock assessment.
Dr. Lisa (Schile) Beers is a coastal ecologist with Silvestrum Climate Associates. She has more than 20 years of experience studying wetland plant ecology, carbon cycling, and soil biogeochemistry.
Ninon Martinez serves as the marine monitoring specialist at the University of Belize Environmental Research Institute.
This interview has been edited for length and clarity.
Q: Lisa, as a coastal ecologist, can you explain the role mangroves and seagrass ecosystems play in helping communities build resilience in a changing climate?
Beers: One of the main ways is by protecting shorelines from storm surges and waves. Mangrove roots are extremely effective at slowing currents and dampening waves, even in a stand of trees that’s only a couple meters wide. Areas with intact seagrass beds and mangroves experience less erosion and flooding as a result.
Q: What else do mangroves and seagrass do?
Beers: These ecosystems serve as important nurseries and habitat for many fish and invertebrate species, such as conch, that are important food sources for local communities. And they filter nutrients and sediments out of tidal waters, increasing water quality and clarity that helps promote healthy coral reef systems.
Q: Ninon, what can you tell us about the importance of these mangroves and seagrass habitats in Belize?
Martinez: Mangrove and seagrass habitats are very much part of daily life in Belize’s coastal communities. Fishermen use them as fishing grounds; they protect people’s properties during hurricanes; and you might see kids climbing or swinging from red mangroves to go swimming. These two systems provide biological benefits, economic benefits, and an amazing amount of ecosystem services, so they’re immeasurably important, especially with climate change looming as a threat to our communities.
Q: You mention the role that coastal ecosystems such as mangroves and seagrass play in mitigating the impact of climate change. One way they do that is by capturing and storing carbon. So, Lisa, what happens to this carbon if these areas are destroyed or degraded?
Beers: The main reason that mangrove and seagrass soils sequester so much carbon is that organic matter decomposition rates are reduced dramatically in soils saturated with water because there’s little to no oxygen. So this carbon from dead roots and leaves can be stored for many centuries, even millennia, when kept wet.
But when mangrove ecosystems are removed, diked, and filled for development, not only is the physical tree completely lost, but the soils are exposed to oxygen and begin to rapidly decompose because they’re so organic. And all this carbon is then emitted into the atmosphere in the form of carbon dioxide, further exacerbating climate change. Additionally, the loss of these ecosystems ultimately leads to land subsidence, which can make an area much lower than sea level and very vulnerable to flooding and storms.
Q: What about these ecosystems’ role in protecting against coastal erosion?
Beers: The presence of mangrove and seagrass vegetation reduces water flows and waves. So when these systems are disturbed or removed, their wave-buffering effect is lost and results in a faster rate of coastal erosion on a day-to-day basis, and greater risk of inland flooding and large-scale erosion when storm surges or hurricanes occur.
Q: Tell us about this project to measure the carbon in Belize’s mangrove ecosystems.
Beers: It’s a large-scale scientific research project, the first of its kind in Belize—which is one of the leaders as a Small Island Developing State in understanding and promoting the importance of mangrove and seagrass ecosystems in building climate resilience. This project provides an assessment of the carbon stored in Belize’s mangroves and directly links to protection and restoration targets the country put forward in its recent NDC.
Q: How was the study done?
Beers: Our team of local and international partners conducted field work across the country’s entire coastal region, from Sarteneja to Punta Gorda, including mainland and island sites. We wanted to understand how variable these carbon stocks are across and within mangrove areas and also in degraded and minimally disturbed sites, so we looked at above- (trunk and branches) and belowground (roots) biomass in trees and in the soils beneath them. We nondestructively measured trees using standardized methods to calculate tree biomass and carbon stocks and collected soil cores up to 3 meters in length, from which we’re working in the laboratory to quantify the organic carbon content. The data should give us a strong understanding of how much carbon stocks are held throughout the country.
Q: And how will that information be used?
Beers: Once all the data has been analyzed, it’ll be used to support Belize’s nationally determined contribution, or NDC. It’ll provide the scientific baseline that Belize’s decision-makers need in order to set climate policy. We’ll understand how much carbon could be emitted if mangrove ecosystems are destroyed—and how much carbon could be sequestered if they’re restored.
Q: Ninon, what organizations were involved in the research project?
Martinez: We had an amazing collaboration among international and local research organizations, local and international NGOs, government bodies, community researchers, and even students from across the country. The team members changed as we moved from north to south so the community locals could help guide us with where to go and what to expect. It was an incredibly memorable experience for everyone.
Q. How can countries protect and restore their mangrove and seagrass ecosystems?
Martinez: We have to come from all directions. Protection through policies like the NDCs that countries put forward to meet the goals of the Paris Agreement is absolutely a great step. I think Belize has succeeded with that. We still face challenges with enforcement and educating the public about these policies, but local coastal community members already care about their mangroves and seagrass; it’s inspiring how willing they all are to report illicit activities or help with restoration. We now need to make sure community members understand how to report illegal clearing, what areas are protected, and how they can help with restoration efforts. I don’t think anything can beat local engagement in protecting and restoring these systems.
Q: What aspects of this work did you find to be the most interesting?
Martinez: This was all absolutely new to me. I’d been around these ecosystems my whole life, but I found it phenomenal just how different the different mangrove forests and seagrass meadows in little Belize could be. I loved seeing the color changes in the soil the deeper we cored. It was also incredible to measure trees fatter than a meter and taller than my house—and trees shorter than I am that were hundreds of years old. And I’m only 5’2”! Every single day was interesting, and I’m looking forward to the next time I can get out in the field to do it all again.