Summarised by Centrist
The government is keen to include “blue carbon” in its climate targets. This refers to the carbon stored in coastal and marine ecosystems, such as seagrasses, mangroves, salt marshes, and the ocean floor.
These ecosystems absorb carbon dioxide from the atmosphere and store it in plants, soil, and sediments, helping to reduce greenhouse gases.
The upcoming Emissions Reduction Plan for 2026–2030 is expected to explore these possibilities, which could complement efforts like reforestation.
Rebecca Mills of The Lever Room says the ocean absorbs nine-tenths of the heat humans have added to Earth. “We’re responsible for a big chunk of the planet,” Mills said, adding that marine-based renewable energy and food production could further reduce emissions.
However, bottom trawling in New Zealand’s vast Exclusive Economic Zone (EEZ) disturbs seabed sediments, potentially releasing stored carbon. The EEZ is the area of ocean extending up to 200 nautical miles (370 kilometres) from its coastline.
Marine scientist Geoffroy Lamarche notes that areas like the Hauraki Gulf where carbon-rich sediments from land runoff risk being destabilised. “It’s reasonably well acknowledged that the biggest risk is bottom trawling,” he said.
Dr Robert Hickson, funded by a Government Smart Ideas grant, is researching kelp farms’ ability to store carbon. Hickson’s work focuses on whether carbon-rich detritus from kelp can survive its journey to deep waters, where it might remain locked away for centuries.
