What are mangrove forests?
Mangroves are a group of trees and shrubs that inhabit the intertidal zone (underwater at high tide and above water at low tide) of a coastline. They can be easily recognised by their tangled root systems. It is these root systems that enable mangroves to withstand the forces of the daily rise and fall of the tides. Mangrove forests are unable to withstand freezing temperatures and so are only found at tropical and sub-tropical latitudes.
What benefits do they bring to our climate?
Similarly to land forests, mangroves capture and store carbon, removing it from our atmosphere. However, mangroves have a greater carbon storage capacity than a typical land forest with some studies finding they can store up to 50 times more! It is thought that mangroves store 20 billion tonnes of carbon worldwide, that is a lot of carbon..
You might be wondering why they can store more carbon that a typical forest. Trees and plants absorb and store CO2 through photosynthesis throughout their life. Eventually, parts of the plant fall off into the soil and decompose – at this point some of the CO2 that was locked in the plant is released into the atmosphere. The difference with mangroves is that their tangled roots trap CO2 in the waterlogged soil, preventing CO2 from reaching the atmosphere. This CO2 can remain stored in mangroves for thousands of years, providing that the mangrove forests remain intact.
Aside from their incredible carbon storage ability, mangroves are critical in protecting the land from rising sea levels and coastal erosion as well as providing a sheltered habitat for many species. They provide a natural barrier to some of the most devastating natural disasters.
What threats are mangroves facing?
These incredible plant species are under serious threat from human activity. Over half of mangrove forests across the globe have been lost as a result of human impact. From using the trees for timber to creating space for coastal developments, the rate of mangrove destruction is alarming. If we continue at this rate, there will be no mangroves remaining in 100 years from now. As discussed earlier, mangroves have an incredible carbon capture ability. This means that when they are destroyed, a huge amount of carbon is released into the atmosphere. So in the destruction of mangrove forests, not only are we destroying the potential of further carbon capture, we are also releasing carbon that has already been captured back into the atmosphere. The destruction of mangroves isn’t just a concern for our global emissions, it is a huge concern for surrounding communities. Without mangrove forests, local communities are at a greater risk to natural disasters and livelihoods such as fishing are threatened.
What about conservation of mangroves?
The conservation of mangrove forests is vital not only for the climate but also for many coastal communities and economies. The good news is that conservation projects are being undertaken around the world. A great example is Sri Lanka. Sri Lanka is on route to being the first nation in the world to preserve and replant all of its mangrove forests. A Californian not for profit is providing microloans to those who are leading community mangrove conservation efforts. Alongside the extensive benefits of restored mangrove forests, almost 8000 women and young people have been trained in mangrove conservation and many have been given microloans to create or expand sustainable businesses, benefitting the community.
With more projects like this being funded around the world we have the ability to recover the damaging effects humans have had on our global coastal mangroves. This will not only increase our global carbon sequestration capacity, but will also restore biodiversity and stabilise ecosystems.