A new study that mapped the “blue carbon” uptake from marine and coastal ecosystems around the world highlights how natural sinks and climate change redistribute wealth around the globe.
To win the Race to Zero, we must reconnect with the ocean
The ocean is the cradle of life and an important pillar of our own evolution, development and economy. It is a defining element of who we are.
The ocean is also a great modulator of climatic stability. It holds 16 times more carbon than the terrestrial biosphere, and has absorbed 31% of the CO2 humans released to the atmosphere and trapped 93% of the excess heat in the biosphere resulting from the massive release of greenhouse gases.
It is no surprise that the ocean is emerging as a key component of the strategies supporting our Race to Zero. What is surprising is how long we have taken to identify the ocean as a source of climate change solutions.
On World Oceans Day, I want to remind everyone that in the 21st century we need the ocean more than ever, but we have to repair our connections with the ocean if we are to receive a wave of ocean benefits.
Hunting, overfishing, pollution, habitat destruction and, more recently climate change, have led to the loss of the abundance of marine life, reflected in the decline in the abundance of great whales and sharks to 10%, and a decline of fish stocks to about 20 to 30% relative to their historical abundance.
We have also lost roughly half of the productive coastal habitats, seagrass meadows, mangroves, salt-marshes, coral and oyster reefs, that once protected our shorelines. In short, we have lost over half of the blue natural capital that our oceans contained, along with the multiple benefits they delivered to society.
Decades of research led to the awareness, just over a decade ago, of the power of conservation and restoration of marine habitats as an actionable, nature-based solution to climate change. Marine “blue carbon” habitats, including highly productive seagrass meadows, mangroves, and salt-marshes act as intense carbon sinks, trapping massive amounts of carbon in their soils.
Carbon is preserved in their oxygen-depleted soils, which, unlike forest soils, are free from the risk of being emitted with wild fires, as there are no fires underwater. For instance, blue carbon habitats typically hold 50 to 100 times more carbon in their soils and remove about 10 to 30 times more CO2 from the atmosphere per year than terrestrial forests do. They are unique and efficient carbon-capture habitats. However, when disturbed the massive stocks of carbon locked in their soils may become unstable and be emitted to the atmosphere, so the loss of about half of their extent has contributed to greenhouse emissions and, therefore climate change.
We have lost over half of the blue natural capital that our oceans contained, along with the multiple benefits they delivered to society
The conservation and restoration of blue carbon habitats is a cost-effective approach to remove excess carbon dioxide and contribute to climate action. Blue carbon projects are best delivered through partnerships between local communities, government and international investors. Businesses around the world are focusing on blue carbon projects in their Race to Zero. This was the approach taken for the mangrove plantation Extreme E, an international off-road racing series that uses special electric SUVs and raises awareness climate action delivered through its Legacy program, is developing together with local NGO Oceanium, to plant one million mangrove trees in Senegal.
Blue carbon projects generate a suite of benefits beyond carbon removal, as these habitats are the first lines of defense of our coastlines, dissipating wave energy and raising the seafloor to partially modulate the effect of sea level rise, while also holding our beaches, and providing key nursery habitats supporting fisheries. Restoring blue carbon habitats repairs ocean health and benefits local communities.
But blue carbon opportunities are not limited to coastal habitats. The collapse of great whale populations and stocks of large marine animals, including fish has also impacted on the capacity of the ocean to process carbon. Marine conservation, including rebuilding the abundance of great whales and large marine animals, may, therefore, also contribute to accelerate oceanic carbon sequestration. Expanding marine protected areas to reach 30% of the ocean by 2030 integrates across the carbon removal benefits healthy marine ecosystems provide, thereby supporting climate action.
Seaweed farming is also emerging as a scalable solution to sequester carbon and displace carbon-intensive products, including synthetic plastics, while producing food and sustainable materials and potentially improving ocean health.
Ultimately, rebuilding the blue natural capital of the ocean, which is based on carbon – living carbon – is an effective pathway to climate action; decarbonizing the atmosphere by recarbonizing the biosphere. In fact, there is a strong nexus between climate and biodiversity.
On one hand, impacts on biodiversity and ecosystems account for about one third of cumulative greenhouse gas emissions, such that rebuilding biodiversity and ecosystems can go a long way in helping win our Race to Zero. On the other hand, severe climate change is a major threat to biodiversity. This is particularly so for vulnerable marine ecosystem, such as sea-ice ecosystems, including a complex food web ranging from microalgae to polar bears in the Arctic, and tropical coral reefs, which IPCC forecasts to suffer catastrophic losses under ocean warming, even if the goals of the Paris Agreement are met.
But, on this World Ocean Day, I wish to alleviate the concerns of those suffering from eco-anxiety to emphasize that acting decisively we can prevail, and to celebrate ocean action as a pathway to win our Race to Zero. Blue carbon actions deliver synergistic solutions targeting both our climate and biodiversity crises. We now know that it is possible to rebuild the abundance of marine life along the course of a human generation – by 2050 – if we start now.
And we do not start from scratch, policies, such as the Moratorium of the International Whaling Commission, the CITES Convention, local and regional policies to avoid pollution, and the rise of marine protected areas and active restoration in the 21st century are harbingers of a wave of ocean recovery that I am confident will be propelled further by actions initiated this year. Indeed, 2021 is the super-year of the oceans.
This year opened with the launch of the UN Decades of Ocean Science and Ecosystem Restoration, and will culminate with setting biodiversity targets post-2020 by the UN Convention of Biological Diversity, an expected agreement within the World Trade Organization to remove harmful fishery subsidies, and a process to agree on a new governance framework for biological resources in the high seas under the UN Law of the Sea. We are hoping 2021 will bring great news for the ocean!
The focus on governmental action is fundamental but not sufficient I see with great hope the emergence of actors beyond national governments, ‘real economy’ actors, committed to achieving net zero carbon emissions by 2050 or earlier. Indeed, the members of the Climate Ambition Alliance are catalyzing the delivery of ocean action, such as Extreme E’s mangrove restoration project in Senegal, or its efforts of protection from the impacts of rising sea level of the most important rockery of green turtles, the gardeners of seagrass meadows, in the Red Sea.
Also, in the Red Sea, the Red Sea Development Company is breaking new ground through the development of a new approach to development, regenerative tourism, aimed not only at conserving, but at improving marine conservation status and activating blue carbon potentials through tourism development. Many business and corporations are following suite and targeting the interface of climate and ocean biodiversity through their Race to Net Zero actions.
In Ocean Day 2021 I welcome business and corporations as new, engaged actors that bring hope that we decarbonizing the atmosphere to recarbonize the biosphere can help us win our Race to Zero while delivering a healthy ocean.
Carlos M. Duarte is a marine ecologist and Distinguished Professor of Marine Science at King Abdullah University of Science and Technology (KAUST), at Saudi Arabia and member of the Scientific Committee of Extreme E
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