What is Blue Carbon?
Blue carbon sequestration is the removal and storage of CO2 by oceanic and coastal ecosystems such as saltmarshes, mangroves and seagrass meadows. By restoring degraded wetland habitats, we lift their capacity to remove carbon from the atmosphere and store it in their soil layers.
The Potential of Blue Carbon
The Nature Conservancy (TNC) in New Zealand is partnering with government agencies, local authorities, researchers, scientists, Iwi and coastal communities to overcome the barriers to effective climate and biodiversity solutions that harness the many benefits of restoring our coastal blue carbon habitats.
By restoring coastal wetland ecosystems so that they capture and store carbon dioxide from the atmosphere, TNC aims to address the dual crises of climate change and biodiversity loss. To achieve this, TNC is investing in scientific research and mapping, pursuing pilot projects and providing recommendations for enabling blue carbon markets.
Coastal wetlands are globally vulnerable to degradation through drainage for agricultural use and coastal development, leading to greenhouse gas emissions, biodiversity, amenity and resilience loss, and limiting their potential as carbon sinks and coastal protection. In addition, the survival of remaining coastal habitats is increasingly endangered by sea level rise and coastal squeeze.
Scientists have shown blue carbon ecosystems in New Zealand can store, or ‘sequester’, as much carbon as native forests.
According to international research by the Global Mangrove Watch, mangrove swamps can store four times more carbon—which is why halting their destruction and restoring and protecting them has become an international priority.
TNC has a track record of developing blue carbon projects across Central and North America, China, Indonesia, Papua New Guinea and Australia, typically using mangroves, tidal marshes and seagrass habitats. Some of these projects have already begun generating blue carbon credits on the voluntary carbon market.
Restoring coastal wetlands at scale could offer multiple win-wins for climate, biodiversity and communities. Here in Aotearoa New Zealand, our Blue Carbon project is making progress as it builds the evidence base for the carbon removal benefits and demonstrates how these projects can be designed and delivered using a partnership model.
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Scientists have shown blue carbon ecosystems can store, or ‘sequester,’ as much carbon as native forests.
Why Are Wetlands Important?
Coastal wetlands such as the Robert Findlay Wildlife Reserve at Pukorokoro Miranda and Wakapuaka near Nelson provide unique habitats for many native species including plants, fish, macro-invertebrates and birds. Many of these species have evolved to thrive in wetland habitats and are threatened by extinction when wetlands disappear.
Wetlands are part of the earth’s natural flood defences—acting as a giant sponge to soak up water, filter pollutants out of our freshwater and prevent sediment from reaching the sea. They are also efficient carbon stores and can play an essential role in mitigating climate change.
Coastal communities can reap benefits from healthy coastal wetlands in the form of increased flood protection, enhanced biodiversity, cleaner water and opportunities for eco-tourism. They can also enjoy the improved social and cultural outcomes from living in a healthy functioning ecosystem.
Coastal Wetlands and Voluntary Carbon Markets
Restoring a wetland’s carbon storage capacity (as well as its natural habitat and biodiversity) can help make the site eligible to generate carbon credits, which can be traded on voluntary carbon markets. Carbon credit prices on the voluntary carbon market range widely depending on the quality of the credit and associated co-benefits.
Blue carbon restoration can be carried out on a range of sites, including degraded or modified land that was previously a coastal wetland. Restoration work can involve simply restoring tidal flows by removing barriers, or may require more advanced intervention and engineering such as filling in drainage canals or installing culverts.
Unlike growing forests, saltmarsh plants might only take a couple of years to re-establish, provided that the site conditions are favorable for re-establishment.
What We're Doing
TNC NZ is investigating the feasibility of carbon and biodiversity credits. Markets are rapidly evolving, driven by global carbon and biodiversity goals, increasing regulation and increasing awareness of the way that business and society depend on nature.
Blue Carbon Credits Feasibility Study
TNC NZ studied 7 sites to investigate the potential of coastal wetlands to store carbon, provide rich biodiversity habitats and offer biodiversity and carbon credits to fund restoration work.
The study found that all sites in the study would have the potential to capture carbon and generate blue carbon credits. The extent to which those credits cover the costs of restoration depend on the price carbon can be sold at, the scale of the project and the complexity of restoration. TNC NZ is continuing work to investigate finance options for restoration of coastal wetlands.
We are now scoping a pilot restoration project to further advance our understanding in practice.
Market Analysis
Deloitte NZ and TNC NZ are jointly researching the market demand for New Zealand’s voluntary carbon and biodiversity credits, supported by BNZ. This work will assess both international and domestic demand for carbon and biodiversity credits from New Zealand, with the aim of providing clear insights into market potential and identifying the requirements for attracting investment in New Zealand projects.
To learn more, please contact us at newzealand@tnc.org.
Market Conditions
A 2024 report commissioned by TNC and the Ministry for the Environment (MfE) explored the policy, legal and market conditions that would be needed to enable coastal wetlands projects to result in blue carbon credits. The report also recommended ways to address the existing policy, regulatory and legal complexities so that New Zealand projects could participate in voluntary carbon markets at scale, and help accelerate coastal wetland restoration in Aotearoa New Zealand.
Filling Dataset Gaps
Developing blue carbon projects effectively requires more scientific knowledge than we currently have, for example, the rates at which carbon is captured in different parts of the country, or in different ecosystems. This information will also help develop appropriate policy and make future decisions on blue carbon within carbon credit schemes and Aotearoa New Zealand’s Greenhouse Gas Inventory (NZGHGI).
Following the policy research report above, MfE and TNC NZ, with the support of the BNZ Foundation, are working in partnership to develop a comprehensive quantitative coastal blue carbon dataset for New Zealand to help make coastal restoration more effective and accelerate the supply of blue carbon credits.
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