What is blue carbon?

Blue carbon refers to the carbon that is stored in coastal and marine ecosystems, such as mangroves, salt marshes, and seagrasses. These ecosystems play a crucial role in mitigating the impacts of climate change by absorbing and storing significant amounts of carbon dioxide (CO2) from the atmosphere. The carbon that is stored in these ecosystems is called “blue carbon.”

Why is blue carbon important?

The importance of blue carbon lies in its potential to mitigate climate change. By conserving and restoring coastal and marine ecosystems, we can increase the carbon sequestration capacity of these ecosystems and reduce the amount of CO2 in the atmosphere. Additionally, blue carbon ecosystems also provide numerous other ecosystem services, including shoreline protection, habitat for fish and other wildlife, and supporting livelihoods for local communities. It is imperative that we protect these blue carbon ecosystems.

Blue carbon is facing danger from human-driven activities

To use the word “protect” hints that blue carbon ecosystems are being threatened. It is true that these ecosystems are threatened by human activities, such as coastal development, pollution, and overexploitation of resources. The destruction of these ecosystems not only results in the loss of important habitats, but also releases the stored carbon back into the atmosphere, contributing to climate change.

Seagrass can capture carbon from the atmosphere up to 35 times faster than rainforests, and can store up to 1,000 tonnes of carbon per hectare proving superior to terrestrial ecosystems. But in a Blue Carbon report by the United Nations Environment Programme, the loss of these ecosystems are in rapid decline. For example, the loss of global seagrass area increased from less than 1% in 1970s to 7% since 2000s.

Furthermore, the losses are already affecting livelihoods and threatening food security where fishery and aquaculture are the main pillars, not to mention how it can accelerate the climate crisis.

What is the difference between blue carbon and green carbon?

The difference between blue and green carbon is the location of the carbon storage, with green carbon stored in terrestrial ecosystems and blue carbon stored in coastal and marine ecosystems. Both types of carbon storage play a critical role in mitigating climate change and maintaining the health of the planet.

Examples of blue carbon ecosystems in Japan

One of the most well-known blue carbon ecosystems in Japan is the Seto Inland Sea, which is located between the main island of Honshu and the islands of Shikoku. This area is known for its rich biodiversity and is home to many species of fish, sea mammals, and birds, as well as various types of coral reefs and seagrass beds.

Another famous coastal ecosystem in Japan is the Oki Islands in the Sea of Japan, home to unique plant and animal species, and several important seabird colonies. The Oki Islands are also home to a number of traditional fishing communities and are recognized for their cultural and ecological significance.

The Iriomote Island, located in the Okinawa Prefecture, is known for its diverse tropical and subtropical mangrove forests and coral reefs, which are home to a variety of plant and animal species, including several species that are endemic to the area.

Examples of blue carbon activities in Japan

The government of Yokohama City in Kanagawa Prefecture is taking a leading role in the implementation of “Yokohama Blue Carbon“. Out of the 140 km of coastline in the city, approximately 1 meter in Kanazawa Ward is preserved as an eelgrass bed. “Yokohama Blue Carbon” was launched in 2014 as a carbon offset certification and trading system. It combines “Blue Resources” with blue carbon to reduce and trade CO2 emissions in the coastal areas of Yokohama. This innovative initiative is unique in the world and was certified with Blue Carbon in 2019.

Sachiumi Heroes in Yokohama City is an excellent example of regenerative blue carbon farming. Seeing the potential of kelp as a more powerful sequestration agent than cedar trees, director Tatsunori Tomimoto works with local famers to promote kelp farming and combat the climate crisis.

Regenerative kelp farming for blue carbon in Yokohama

In 2020, Fukuoka City launched the “Fukuoka City Hakata Bay Blue Carbon Offset Program”. This program uses a portion of the entrance fee for the Hakata Port, donations from companies, and sales of blue carbon credits to support environmental conservation efforts, including the creation of eelgrass beds.