The oceans contain 50 times more carbon despite the atmosphere, they act as a thermostat for the planet. The ability to use technology to increase this capacity to absorb carbon dioxide (CO2) is at the heart of the many ideas driving the development of Ocean Based Climate Interventions (OCBI) technologies. An international team of scientists, including two Portuguese, publishes this Friday in the journal Science a call for reflection on the potential impacts of these technologies on deep-sea ecosystems.
“We are not against the OBCI, we want it to be reflected in an organized way, based on scientific knowledge and that the whole process is transparent in relation to its possible effects,” they told PÚBLICO, from e-mailAna Colaço, from the Institute for Research in Marine Sciences – Okeanos, at the University of the Azores, and Nélia Mestre, from the Center for Marine and Environmental Research at the University of the Algarve, two of the authors of the article in Science.
What are we talking about when we talk about OBCI? “There are several proposed techniques that add substances or place structures in the sea reduction of climate“, the two researchers explain. Examples are varied. For example, fertilizing the oceans and cultivating macroalgae to sink to the seabed, with the aim of enhancing the natural processes through which marine organisms absorb carbon dioxide through photosynthesis.
“Ocean fertilization has techniques patented by companies (for example, GreenSea Venture), while other companies are looking for funds to start commercially on a large scale,” explains Ana Colaço.
On the other hand, macroalgae are already cultivated in many countries, for animal feed, food or to become energy sources. In Norway there is talk of growing macroalgae and sinking them into the fjords, says Ana Colaço. “They can be a good way of sequestering CO2. However, on a large scale and associated with the infrastructure to be deposited on the seabed, they could destabilize the extremely stable and sensitive environment that is the deep seabed and affect its functions and services. ecosystem important to keep the planet healthy,” adds the scientist from the University of the Azores.
“Imagine the bottom of the anoxic sea [sem oxigénio]”, asks Ana Colaço “This will affect the nutrient recycling ecosystem services”, fundamental to the production of the oxygen we breathe.
Another technological idea being talked about is to try to remove gases with the greenhouse effect of the atmosphere is to inject liquid CO2 into deep water, or even under the seabed, to try to speed up carbon dioxide sequestration processes, the scientists report in the article published in Science.
“If there are leaks, it could have serious consequences, as all the carbon deposited on the seabed in the form of shells and other carbonaceous structures could be released again,” warns Ana Colaço.
This would lower the pH not only at the surface, but also in deep water, increasing the acidity of the oceans, which is already a problem today. It harms many forms of life: it prevents the growth of species with a calcium carbonate shell or skeleton, such as e.g. corals and molluscs, for example.
But the technological proposal could also involve alkalizing the oceans to increase the process of sequestering CO2 from the atmosphere. “It plans to add alkaline materials to seawater or separate surface water into acid and base by electrochemical methods and then transport the acidic component to depths greater than 2000 meters,” says Nélia Mestre.
For now, these ideas are just concepts. “To have the desired effect, they will have to be applied on a large scale, which can cause a corresponding scale of impact (possibly very negative) on ecosystems,” warn the two Portuguese authors of the article, Ana Colaço and Nélia. Master.
“All these techniques are disturbing and many new ideas are emerging, for example through idea competitions like Xprize”, explains Nélia Mestre.
Hence the idea of the article at Sciencewhich calls for a “coordinated and integrated” approach to establishing decision-making processes and assessment standards for ocean-based climate interventions.
“These actions can be regulated through the United Nations Convention on the Law of the Sea (UNCLOS), the Convention on Biological Diversity (CBD), the 1972 London Convention and the 1996 London Protocol,” says Ana Colaço . “But there is a need to create its own forum, where guidelines and regulations will be established for this kind of actions,” adds Nélia Mestre.
“The planet needs actions to minimize the impacts climate change, but these must be studied and studied”, warns Ana Colaço, in conversation with PÚBLICO. “But a number of solutions began to emerge, although they had only just been tested [algumas] on a small scale, we see that they can have very harmful consequences’ for the deep sea, the area where Ana Colaço and Nélia Mestre work.
“The article basically serves as a warning. We think it is good that actions are being proposed, but we have to do it think a little and gain more knowledge so that the solution is not worse than the problem”, explains Ana Colaço. “Obviously, energy cannot replace a reduction in carbon dioxide emissions and a more sustainable industry, so it has to be a whole. We caution that we need to stop and think, to study the potential effects of OCBI in a more concerted way,” he insists.
The two Portuguese scientists sign this article Science because they are part of the Deep Ocean Stewardship Initiative. The purpose of this group is to integrate science, technology, policy, law and economics to provide advice on ecosystem management, the use of deep ocean resources and strategies to maintain the integrity of ocean ecosystems within and outside the territory under national jurisdiction.
Works will appear in Portugal
What role can Portugal play in moving forward with caution in these OCBI technologies? “Portugal has a huge marine area and a huge blue economy,” the two scientists begin saying in the response they sent to PÚBLICO. Awareness of these issues is essential, as these projects will appear in Portugal “sooner or later”, they stress.
“Portugal could be a pioneer if it tries to establish rules for these actions, which are starting to take shape and have pilot studies in various places,” defend Ana Colaço and Nélia Mestre. The potential impacts of OCBI technologies know no bounds, so without concerted consideration and regulation they will be harmful to the environment. Even if they take place in waters beyond national jurisdictions, on the high seas.
The recently signed High Seas Convention (United Nations Convention on the Sustainable Use of Water) Biodiversity Beyond National Jurisdiction) could bring some help, say the two scientists. At the level of Article 14, which talks about spatial management tools for the protection, conservation, restoration and preservation of biodiversity and ecosystems, as well as in Part IV of Article 21, which establishes the obligation of countries to carry out impact studies on actions in areas outside national jurisdiction.
“All this will make it necessary to regulate OCBI in both national and international waters,” expect Ana Colaço and Nélia Mestre. “Many of these actions can only take place on the high seas, raising questions about the use of the sea in areas outside national jurisdiction, and this treaty obliges states to take this into account.”
But for that to happen, countries must ratify the treaty agreed last weekend.