National blue carbon dataset

Project Overview

In partnership with Cawthron Institute and NIWA, Tidal Research led the development of a groundbreaking national dataset for coastal wetland blue carbon in Aotearoa New Zealand. This foundational work, commissioned by the Ministry for the Environment and The Nature Conservancy, represents the country's first comprehensive compilation of blue carbon data across saltmarsh, mangrove, and seagrass habitats.

Key Outcomes

National Dataset Creation: Compiled 85 individual studies into a standardised dataset covering five key measurements: soil organic carbon (SOC) stocks, soil carbon accumulation rates (CAR), above-ground biomass (AGB), below-ground biomass (BGB), and greenhouse gas emissions across New Zealand's coastal wetlands.

Carbon Credit Framework Support: The dataset directly informs frameworks for potential inclusion of coastal wetlands into compliance and voluntary carbon credit schemes, providing essential default values where site-specific data are unavailable.

Research Gap Analysis: Identified critical data gaps through comparison with Australian temperate datasets, providing strategic guidance for future data collection to strengthen New Zealand's blue carbon science base.

Policy Integration Pathway: Created a foundation for incorporating coastal wetlands into New Zealand's Greenhouse Gas Inventory (NZGHGI), supporting the country's climate commitments under the Paris Agreement.

Impact

This work establishes the scientific foundation for recognising coastal wetlands as nature-based climate solutions in Aotearoa New Zealand. With an estimated 87,861 hectares of land potentially suitable for blue carbon restoration projects, the dataset enables evidence-based decision-making for coastal restoration priorities and carbon market participation. The standardised approach ensures data consistency and credibility across multiple carbon abatement methodologies, reducing barriers to blue carbon project development.