The Colors of Carbon Sinks: What They Mean, Why They’re Important

Blue carbon, green carbon, brown carbon… Do you know your carbon colors? Carbon sinks are an essential element of the carbon cycle and each type has an important role to play in fighting climate change.
3 min readMar 21, 2022
Photo by Afifi Zulkifle on Unsplash

Carbon can be stored anywhere!

Just some places are more efficient than others. A natural carbon sink is any system or place that absorbs more carbon than it emits, stocking it for future use. In the case of climate change and mitigation solutions, natural carbon sinks are an important resource that needs protection and regeneration to help restore a balanced carbon cycle and nature.

But not all carbon sinks are created equal. If you’ve been following up to this point but the terms “blue carbon,” or “green carbon,” or less often, “brown or black carbon”, have you confused, don’t worry. They’re actually pretty logical ways of describing carbon sinks found in water (blue), land (green), and underneath the Earth’s surface (brown or black).

Blue — Oceans and Coastal Ecosystems

According to the International Union for Conservation of Nature (IUCN) Report, 83% of global carbon is circulated in oceans and coastal habitats¹. And although coastal ecosystems cover only 2% of the world’s “blue” areas, they can store more carbon than the same area of terrestrial forests.


A type of coastal ecosystem that needs both saltwater and dry periods, mangroves store carbon below ground. Indonesia is home to large swaths of mangroves that store up to 3.1 billion tons of carbon per year², or nearly 3 times global aviation emissions³.


Waterlogged all year long, with very slow decomposition times, peatlands stock enormous amounts of carbon — it is estimated intact peatlands hold up to 44% of the world’s soil carbon. It is in our interest to restore them: damaged peatlands release up to 5% of greenhouse gases annually.

Global distribution of blue carbon ecosystems. Source: (The Blue Carbon Initiative, 2019).


Green carbon sinks refer to those natural carbon sinks found on land, primarily grasslands, croplands, and forests.


Grasslands store carbon in the soil and not in their external stems or leaves, which are more vulnerable to drought or fire. In places like California, where drought and fires are becoming more common, grasslands are being considered a reliable option for carbon sinks⁴.


Transforming agricultural fields into carbon sinks is a strategy that gets a lot of media coverage because it could help reduce agriculture’s net emissions. In Europe, sequestering carbon in agriculture fields is a key part of the Farm to Fork strategy, the agriculture-specific strategy of the Green New Deal.


Global forests are estimated to absorb 7.6 billion metric tons of carbon dioxide annually — 1.5x more than the United States annual emissions⁵. For example, the Amazon rainforest is in danger of crossing the threshold from rainforest to savannah⁶.

Other carbon sinks

Other carbon sinks you might hear about are fossil fuel deposits (sometimes called brown carbon) and the atmosphere. Can we use these as carbon sinks towards climate balance? Not really. Fossil fuel deposits take millions of years to transform carbon, and the atmosphere is already holding more carbon than it should.

Carbon Sinks as a Tool for Change

Protecting and restoring the Earth’s carbon sinks is critical in rebalancing the carbon cycle. At CarbonABLE our mission is to regenerate the world’s natural carbon sinks.



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