by Louise-Océane Delion, marine biologist and scientific content creator for Koraï
Introduction
We are facing today an unprecedented situation: our human activities and our way of living and consuming on this planet have deregulated many natural systems, threatening both our survival and that of many other species.
Climate change is a perfect example... The increase in the concentration of greenhouse gases in the atmosphere due to human activities is unique in human history. The consequences of this climate disruption are being felt in all four corners of the world, notably in the form of extreme climatic events: droughts, floods, forest fires, heat waves, cold waves, hurricanes, etc.
While it is more than urgent to reduce now our emissions of greenhouse gases (such as CO2), it is also crucial that we put in place solutions to both mitigate and adapt to the impacts and consequences of climate change, and to do so right now.
Thankfully, we already have the tools in hand. We don't need to look at geo-engineering or take refuge in a theory that technology alone will save us because when we look at what the living world has been doing and being for thousands of years, we can find the solutions we need.
One of our best allies in both mitigating and adapting to the effects of climate change is the ocean - for multiple reasons. In this article, we focus on coastal ecosystems - mangrove forests, seagrass meadows and coral reefs - and their powerful role in helping us cope with the climate crisis. Find out with us why these ecosystems are our best allies and why it is urgent and necessary to preserve and regenerate them.
A carbon story
The current climate crisis is partly caused by the increase in carbon in the atmosphere, which is itself caused by our human activities, which rely on carbon resources such as oil and coal.
As carbon levels in the atmosphere increase, there is a need to consider how to reverse this situation by increasing carbon levels in the soil, both by capturing/absorbing more of it and by storing/burying it over a long period.
In this case, mangrove forests and seagrass meadows become key players as they are considered to be two of the most carbon-capturing and storing ecosystems on Earth.
Through the process of photosynthesis, mangrove trees and seagrass meadows capture carbon through their branches, trunks, leaves, stems, etc.
Their roots also collect a tremendous amount of organic matter (leaves, branches, animals... and therefore carbon matter) via the flow of water. This material will then be buried with the rest of the sediment, locking up a lot of carbon in the soil - potentially for thousands of years if the soil is not disturbed. Mangroves and seagrass meadows then become true carbon 'sinks', capable of storing up to 2-4 times more carbon than tropical forests1.
These two coastal ecosystems, therefore, appear to be two of our best allies in limiting and mitigating climate change as much as possible, by capturing and storing part of the excess carbon present in the atmosphere
Adapting and protecting ourselves
Coastal ecosystems such as mangrove forests, seagrass meadows and coral reefs are also our best allies in mitigating the consequences of climate change that directly affect coastlines and coastal populations.
By creating structures in the water column (corals, seagrass beds) and at the boundary between the sea and inhabited areas (mangroves), these habitats reduce the energy of waves coming from the open sea, reducing their impact on the coast: they act as natural barriers. As a result, these ecosystems protect coastlines from erosion, flooding, hurricanes, storms and other extreme weather events - all of which are increasing as a consequence of climate change.
Taking care of these ecosystems for our survival
Given the magnitude of the current climate crisis, there is an urgent need to put in place solutions to mitigate and adapt to climate change.
Marine ecosystems such as mangrove forests, seagrass beds and coral reefs are emerging as some of our best allies in both mitigating and coping with climate change. Their ability to capture and store carbon, while protecting coastlines from climatic events, makes them essential habitats at the heart of the solution.
However, these ecosystems are also facing unprecedented anthropogenic pressures. Their degradation and loss only hinder their natural capacity to act as carbon sinks and natural barriers. It is partly for these reasons that we must continue to protect these habitats and, where they have already been damaged, help them to regenerate.
Although Africa has barely contributed to climate change (only responsible for 4% of the global greenhouses emissions), it is the most impacted continent by the effects of climate change (high temperatures, extreme droughts, sea level rise, floods...) with many consequences for the populations of African countries who are facing increasing food insecurity, water stress and forced displacement2.
For example, although water scarcity already impacts many people in Africa (1 out of 3 people), climate change and its consequent droughts will worsen it. Up to 230 million Africans (16% of the population) will face water scarcity, and twice more (430 million - 32%) will live in water-stressed countries3.
Another dreadful consequence is the number of people who will need to migrate within their own countries to find a new space with better (or less bad) living conditions created by climate change. In Africa, more than 105 million people will be forced to migrate, representing half of the global human migration due to climate change4.
With more than 117,000 km2 of mangroves, seagrass beds and coral reefs5, Africa also has the capacity to participate in the mitigation of climate change on a global scale, while protecting its coasts in a more local context, which are also strongly affected by its consequences.
This is exactly why Koraï exists: to enable the regeneration of African coastal ecosystems. Will you join us?
References
2 Association, W., 2022. State of the Global Climate 2021, World Meteorological Association. Switzerland. https://policycommons.net/artifacts/2434625/1290_statement_2021_en/3456217/ CID: 20.500.12592/khwc9c.
3LA BANQUE AFRICAINE, DE DEVELO PP et BANKGROUP, AFRICANDEVELOPMENT. The Africa water vision for 2025: equitable and sustainable use of water for socioeconomic development. Economic Commission for Africa: Addis Ababa, Ethiopia, 2000.
4Clement, Viviane; Rigaud, Kanta Kumari; de Sherbinin, Alex; Jones, Bryan; Adamo, Susana; Schewe, Jacob; Sadiq, Nian; Shabahat, Elham. 2021. Groundswell Part 2 : Acting on Internal Climate Migration. World Bank, Washington, DC. © World Bank. https://openknowledge.worldbank.org/handle/10986/36248 License: CC BY 3.0 IGO.”
5Tregarot, E., Touron-Gardic, Gré., Cornet, C.C., Failler, P., Valuation of coastal ecosystem services in the Large Marine Ecosystems of Africa, Environmental Development (2020), doi: https://doi.org/10.1016/j.envdev.2020.100584