The 2022 report “The State of the World’s Mangroves” estimates that since 1996, 5,245 square kilometers of mangroves have been lost due to human activities such as agriculture, logging, tourism development, coastal aquaculture and climate change, and that only 147,000km2 remain. It is a well-known fact that mangrove forests are among the most productive marine ecosystems in the world, located at the very start of the marine food web (the productivity of biomass by plants is called primary productivity). They serve as a natural nursery for fish and also provide protection against coastal erosion.
One of the primary causes of mangrove forests’ decline is illegal logging for timber and charcoal production, which had caused thousands of square kilometres of mangroves to disappear. This process needs to not just be stopped, but also reversed, and urgently. All mangrove forests need to be conserved and restored if we are to achieve the United Nations’ Sustainable Development Goals, in particular SDG 14, life below water; SDG 15, life on land; and SDG 7, affordable and clean energy, in the context of accelerating climate change.
At the same time, wood offers a renewable alternative to fossil fuels such as coal, oil and gas, which are the leading drivers of climate change. Wood is also a safe raw material, as it’s fully recyclable.
So how can we balance these two urgent needs?
One idea being tested is the feasibility of forests floating on the ocean.
Floating mangroves have been tested at an experimental site, for the sake of greening a floating boat jetty. To better understand their larger-scale development, we need to find out more about energy, mooring, and transport requirements, financial feasibility and maintenance cost. Other important issues include the design of the structures on which the mangrove forests would grow and the materials used – recycled ocean plastic debris is one option.
Data are expected to be provided by the University of New South Wales, in an upcoming study that will be carried out in the Pacific Ocean.
Floating mangrove plantations wouldn’t replace shoreline forests, but would serve to reduce resource pressures on them. Coastal management that integrates floating plantations with shore-based mangroves would strengthen ecosystem services. Further, design and location of the “pontoons” – the containers on which the mangroves grow and float – would offer additional wave attenuation and a measure of coastal protection.