Blue carbon: Could a solution to the climate challenge be buried in the depths of fjords?
- Media Manager
- Jun 7, 2023
- 2 min read
phys.org
The Conversation
Written By: Rebecca J McLeod and William Austin
Published: June 8th, 2023
Cyclone Gabrielle has highlighted forestry slash as a problematic aspect of relying on plantation forests to draw down carbon dioxide (CO₂) from the atmosphere.
While we no doubt must prioritize reducing emissions, we will have to find other effective methods of CO₂ removal. This includes protecting and restoring natural carbon sinks.
Aotearoa New Zealand is a maritime nation with 94% of the continent of Zealandia under water. Marine sediments provide the largest store of organic carbon on Earth, so why aren't we looking to the sea as we plan our way out of the climate crisis?
The concept of blue carbon (carbon captured by the marine environment) was coined around 15 years ago. But it is only this week, as the UN Framework Convention on Climate Change (UNFCCC) meets in Germany in preparation for the next climate summit in November, that blue carbon is emerging as a mainstream global option for carbon sequestration and accounting.
Blue carbon opportunities are varied, but it makes sense to focus first on the most productive marine carbon sinks. Research shows that fjords in temperate areas such as New Zealand's Fiordland and in Scotland have some of the highest potential for carbon storage.
Blue carbon opportunities range from the restoration of wetlands to seaweed farming. They differ markedly in the scientific understanding of the rate and permanence of carbon sequestration—and how ready they are to be developed into climate change policy. The challenge lies in reliably measuring where and how fast carbon is being stored long term.
This can prove particularly challenging in scenarios where the place of carbon deposition (such as deep ocean sediments) is far removed from the place of carbon capture (the surface waters where photosynthesis occurs).
