Skip to content

A preliminary estimate of the contribution of coastal blue carbon to climate change mitigation in New Zealand

Published Article

New Zealand

Publication date: September 13, 2023

File format: url

View resource

This study provides a preliminary estimate of coastal blue carbon in New Zealand, assessing carbon stocks and sequestration across saltmarshes, mangrove forests and seagrass meadows. It highlights current ecosystem extent, restoration opportunities and the role of blue carbon in national climate change mitigation and adaptation strategies.

Subject Tags

  • Carbon storage
  • Carbon markets

Abstract

The scale at which New Zealand is currently storing and sequestering blue carbon, and could create additional blue carbon via restoration, has been unclear. Here, we calculate a preliminary estimate for the current extent of three key blue carbon ecosystems (saltmarshes, mangrove forests and seagrass meadows), their carbon stocks and their carbon sequestration rates using the best available data to provide a preliminary estimate of blue carbon in New Zealand. We also use local examples to explore opportunities to create additional blue carbon. Based on the available literature, we estimate the current extent of New Zealand's blue carbon ecosystems to be 76,152 ha, which is 1.0% of the area of terrestrial native forests. Our preliminary estimate of New Zealand's blue carbon stock is 2.66–3.76 Mt of carbon, with a current carbon sequestration rate of 0.12 (0.05–0.26) Mt/CO2/yr, which is equivalent to 0.16% of New Zealand's 2021 gross emissions. Restoration of saltmarshes could enhance their carbon sink capacity, mangrove forests are naturally expanding and seagrass meadow restoration techniques at scale are still in development. Developing a national framework for blue carbon protection, monitoring and restoration is important as part of New Zealand's climate change mitigation and adaptation efforts.

Citation

Ross, F. W., Clark, D. E., Albot, O., Berthelsen, A., Bulmer, R., Crawshaw, J., & Macreadie, P. I. (2024). A preliminary estimate of the contribution of coastal blue carbon to climate change mitigation in New Zealand. New Zealand Journal of Marine and Freshwater Research, 58(3), 530-540.

TNC Authors