'Nature-based solution' proposed to facilitate carbon reduction

BEIJING -- Chinese researchers have proposed a "nature-based solution" to contribute to achieving the country's carbon neutrality goal.

The researchers from the South China Botanical Garden, Chinese Academy of Sciences, figured out that protecting and restoring coastal blue carbon ecosystems (BCEs) can be a key strategy for carbon reduction, according to a research article recently published in the journal Innovation.

China has announced that it will peak carbon dioxide emissions by 2030 and achieve carbon neutrality by 2060. "In addition to large-scale emission reduction and decarbonization, it is also necessary to increase carbon sinks through natural ecosystems," said Wang Faming, the first author of the article.

The BCEs, such as mangroves, salt marshes, tidal flats and seagrass meadows, have an efficient carbon dioxide storage capacity. Therefore, protecting and restoring the ecosystems are considered an important "nature-based solution" for climate adaptation and mitigation.

China stores up to 118 Tg carbon, in terms of weight, across a total area of about 1.44 million hectares BCEs, including over 75 percent as non-vegetated tidal flats, the article noted. In addition to carbon storage, the carbon burial capacity of these BCEs should also be noted.

The total carbon deposits in non-vegetated coastal flats are from 0.28 to 1.5 Tg each year in China.

The BCEs typically have very low methane emissions, according to Wang. "The total methane emission of mangroves is about 0.01 Tg per year, while those from salt marshes and coastal flats need to be further calculated."

The researchers estimated that protecting the country's existing BCEs can cut carbon emissions by 0.47 to 1.79 Tg per year.

During the 20th century, the global coastal wetlands were reduced by 25 percent to 50 percent due to human activities, said the article, adding that China plans to restore mangroves to 48,650 hectares over the next eight years, which is expected to further absorb 0.1 Tg of carbon per year.

The article analyzed potential practices and techniques to improve the functions of the coastal BCEs, including fertilization, biochar application and adding iron.

The practices and techniques should be balanced between improving the carbon sink of the BCEs and protecting the natural ecosystem, according to the researchers.

In addition to helping fight climate change, protecting the BCEs also provides other cost-effective benefits, including storm protection, shoreline stabilization, water conservation, purification, high biodiversity and productivity, the research article noted.