R. Phyland (Jacobs Group Australia (Pty) Ltd), N. Pontee (Jacobs UK Ltd), K. Simmonds (Jacobs New Zealand Ltd).
The risk of climate-related disasters is increasing and strategies to mitigate climate change are needed. Coastal ecosystems, including mangroves, tidal marshes and seagrasses, sequester and store "blue" carbon and are an essential piece of the climate change solution.
83% of global carbon is circulated through the ocean. Coastal habitats cover less than 2% of the ocean area, yet account for approximately half of the total carbon sequestered in ocean sediments. When protected or restored, blue carbon ecosystems sequester and store carbon. When degraded or destroyed, they emit the carbon they have stored for centuries. Experts estimate 1 billion tons of carbon dioxide being released annually from degraded coastal ecosystems. Coastal wetland habitats—through the build-up of sediment and vegetation—trap and bury carbon at a greater rate per area than terrestrial habitats such as forests or peatlands.
The potential for carbon captured by coastal ecosystems to contribute to net zero ambitions is attracting significant interest. Jacobs developed the world’s first carbon code for coastal wetlands in 2014 and has extensive experience with coastal ecosystem restoration and climate change adaptation and mitigation. We are designing nature-based solutions that restore coastal ecosystems and developing and trialling a carbon code for U.K. saltmarshes.
Supported by the U.K. Government’s Natural Environment Investment Readiness Fund, the carbon code for saltmarshes project is developing scientific and revenue models, which will demonstrate the carbon benefits of restoring saltmarshes. The need for restoration is pressing since significant areas of coastal saltmarsh have been lost due to land claim and concerns remain over potential losses caused by sea level rise and the presence of coastal defences.
This project is paving the way for investment in restoring the U.K.’s saltmarshes, which will help mitigate climate change, support biodiversity and reduce flood risk. The project has the potential to help attract up to $1.9 billion (£1 billion) of private investment in restoration projects over 25 years, creating up to 22,000 hectares (54,363 acres) of habitat.
A growing number of organizations in New Zealand, Australia and across the globe are committed to achieving net zero by reducing their carbon emissions and offsetting the impacts of essential activities. Closer to home, the Australian Government is consulting on a Blue Carbon Strategy: a proposed new method under the Emissions Reduction Fund.
This paper outlines what blue carbon is and the importance of coastal ecosystems to sequester carbon and mitigate climate change. It draws on the extensive data Jacobs has access to around the potential benefits of restoring mangrove habitats, and the consequences of their decline. It summarises key elements of the carbon code project in the UK to demonstrate its direct relevance to a New Zealand context. It describes how a similar approach could be applied in New Zealand to assess the potential sustainability, scientific and financial opportunities that can be realised through blue carbon sequestration and coastal ecosystem restoration, and the subsequent carbon credits. This paper also outlines the barriers to blue carbon project implementation and options to mitigate these.