Carbon—it’s one of the first factors we talk about in the climate crisis conversation. As a greenhouse gas, the rates of carbon in the atmosphere are too high, causing heat to become trapped in the Earth’s atmosphere and lead to higher temperatures with brutal ecological impacts. The good news is global initiatives to reduce carbon dioxide rates have picked up in speed and intensity over the last two decades.

Since trees capture carbon dioxide while producing oxygen, they’re nature’s first line of defense in carbon capture. In Southeast Asia, home to the most biodiverse marine ecosystems in the world, this takes form in blue carbon wetlands.

Blue carbon wetlands comprise a variety of coastal ecosystems – most notably mangroves, salt marshes and seagrasses – but also include upper estuarine tidal wetlands, and adjacent ecosystems such as salt flats and macro-algal communities. The ecosystems not only provide tremendous value to the societies living in their vicinity but also to humanity as a whole.

These wetlands store large amounts of carbon in aboveground biomass and in soils as their roots trap sediments and expand soil volumes. As a result, blue carbon wetlands have increasingly become important for environmental management of coasts and for use as self-sustaining nature-based solutions in adapting coastlines to rising seas.

Mangrove vegetation is located within the intertidal zone and tolerates but does not always require saline water; mangroves extract freshwater from ultrafiltration of seawater through root tissue and consume freshwater differentially when it is readily available (groundwater, rainfall at low tide). Once water is absorbed by roots and the metabolic costs of excluding salt are incurred, bulk water transport from roots-to-leaves is driven by pressure gradients created as water is transpired. Especially under saline soil conditions, mangroves have been recognized as having high plasticity in adjusting their rates of leaf-level water use efficiency to accommodate osmotic gradients.

The mangroves have an enviable ability: man made structures like smokestacks attempt to capture carbon at the point of its source. Alongside this, Carbon Dioxide Removal (CDR) practices work to remove carbon dioxide from the atmosphere, like when trees remove and store carbon as they grow. But no one captures carbon like mangroves: according to the Blue Carbon Lab, coastal forests capture carbon at a rate 30-50 times higher than terrestrial forests.

In Southeast Asia, any infrastructure project must respect and prioritize the blue carbon habitats on the coastal territories. Without them, the surrounding areas, global ecosystems, and human health would suffer. With them, we will thrive.