Recognisable by their dense tangle of roots making the trees appear to be floating above the water, mangroves are found in tropical areas where seas and air temperature are warm year round. Growing in low oxygen soils, these shrubs and trees line rivers and coasts where they thrive despite the flooding, salinity and sediment buildup.
Mangrove forests line the shores of Milne Bay, one of Cool Earth’s key partnerships with local people in Papua New Guinea. Here, life in the rainforest is also life by the ocean. These seriously tough trees grow in the challenging conditions of intertidal zones – where the rainforest meets the sea. People in Milne Bay have known the many benefits of mangroves to people and planet for generations. But a recent study1 has shown the value of mangroves in the fight against climate change is even greater than we thought. They sequester huge amounts of carbon, not only above but below ground, in their rich soil.
Mangroves are also rich nurseries for juvenile fish. This, in turn, provides food for local communities and larger predators. They also act as a fantastic filter for pollutants and excess sediment2, trapping chemicals from harming coral reefs. Add to this the part they play in defending the coast against storms and rising seas, and you can see why they may be the communities’ greatest asset.
But mangroves are increasingly threatened by human activity and the very climate they help mediate. Research indicates that over a third of the world’s mangrove forests may have been lost between 1980 and 2000.
Swathes of forest are cut to provide space for shrimp and salt farms as well as for wood3.
With mangroves reliant on a steady source of freshwater to grow, rising sea, worsening storms, and increased salinity are taking their toll. In turn, the slew of climate change preventing benefits are lost. When mangrove forests are damaged, the vast quantities of carbon stored in the soil are released as carbon dioxide. In fact, between 2000 and 2015 up to 122 million tonnes of carbon was released due to mangrove forest loss, roughly equivalent to the annual emissions of Brazil4.
Cool Earth is working with local communities in Milne Bay to protect their mangroves and forests from loggers and other threats. Life in the rainforest by the sea is going to be increasingly difficult with increasing climate change. Natural storm barriers and sustainable food sources are going to increasingly become more important. That’s why it’s essential to keep these trees standing strong.