Using the ocean to fight climate change raises serious environmental justice and technical issues | national news

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Sonja Klinsky, Arizona State University and Terre Satterfield, University of British Columbia

(THE CONVERSATION) Heat waves, droughts and extreme weather events endanger people and ecosystems somewhere in the world almost every day. These extremes are exacerbated by climate change, caused primarily by increased emissions of greenhouse gases that accumulate in the atmosphere and trap heat on the Earth’s surface.

With this in mind, researchers are exploring ways to extract carbon dioxide from the atmosphere and lock it in, including using the ocean. But while these techniques may work, they raise serious technical, social and ethical questions, many of which do not yet have clear answers.

We study climate change policy, sustainability and environmental justice. Before people begin to experience ocean health, there are several key questions to consider.

Ocean Carbon Dioxide Removal 101

The ocean covers about 70% of the planet and naturally absorbs carbon dioxide. In fact, about a quarter of the carbon dioxide produced by humans ends up in the ocean.

Ocean carbon dioxide removal is any action designed to use the ocean to remove even more carbon dioxide from the atmosphere than it already does and store it.

It covers a wide range of techniques – from increasing the amount and vitality of carbon dioxide-absorbing mangrove forests to using ocean fertilization to stimulate the growth of phytoplankton that absorb carbon dioxide at building pipelines that pump liquid carbon dioxide into formations below the seabed, where it can eventually solidify as carbonate rock.

There are other forms of carbon dioxide removal – planting trees, for example. But they require large amounts of land that is needed for other essential uses, such as agriculture.

This is why interest in utilizing the vast ocean is growing.

Would these methods store enough carbon?

The first crucial question is whether techniques for removing carbon dioxide from the oceans could significantly reduce atmospheric carbon dioxide and store it long-term, beyond what the ocean already does. Greenhouse gas emissions continue to rise globally, which means that removing carbon dioxide from the oceans should keep carbon dioxide out of the atmosphere for a long time, at least until that greenhouse gas emissions have been reduced.

Early evidence suggests that some forms of carbon dioxide removal from the oceans, such as those that rely on short-lived biomass like kelp forests or phytoplankton, may not store captured carbon for more than a few decades. This is because most plant tissues are quickly recycled through decomposition or by sea creatures grazing on them.

In contrast, mechanisms that form minerals, such as the interaction when carbon dioxide is pumped into basalt formations, or that change the way seawater holds carbon dioxide, such as increasing its alkalinity, prevent carbon from escaping and are much more likely to keep it out. the atmosphere for hundreds or thousands of years.

Ecological risks and benefits

Another key question is what ecological benefits or risks come with different approaches to removing carbon dioxide from the oceans.

Research shows that some options, such as supporting mangrove forests, can promote biodiversity and benefit nearby human communities.

However, other options could introduce new risks. For example, growing and then sinking large amounts of kelp or seaweed could bring in invasive species. The dissolution of certain types of rocks in the ocean could reduce the acidity of the ocean. This would improve the ocean’s ability to store carbon dioxide, but these rocks could also contain trace metals that could harm marine life, and these risks are not well understood.

Each process could also release greenhouse gases, which would reduce its overall efficiency.

Interfering with nature is a social issue

The ocean concerns everyone on the planet, but not everyone will have the same relationship to it or the same opportunities to make their voices heard.

Much of the world’s population lives near the ocean, and some interventions could encroach on places that support jobs and communities. For example, increased algae growth could affect nearby wild fisheries or interfere with recreation. Individuals and communities will assess these risks differently depending on how they are personally affected.

Moreover, people’s trust in decision makers often shapes their view of technologies. Some ways of using the ocean to remove carbon, such as those near the shore, could be regulated locally. It is less clear how decisions about the high seas or the deep ocean would be made, as these areas do not fall under the jurisdiction of any country or global governing body.

People’s perceptions will likely also be shaped by factors such as whether or not they view removing carbon dioxide from the oceans as interfering with or protecting nature. However, views on what is or is not acceptable may change. As the impacts of climate change increase, tolerance for some unconventional interventions appears to be increasing.

It is also a question of ethics

Removing carbon dioxide from the oceans also raises a variety of ethical questions that don’t have simple answers.

For example, it forces people to consider the relationship between humans and non-humans. Is man obliged to intervene to reduce the impact on the climate or should oceanic interventions be avoided? Do people have the right to deliberately intervene in the ocean or not? Are there any specific obligations humans should recognize when considering such options?

Other ethical questions revolve around who makes decisions about the removal of carbon dioxide from the oceans and the consequences. For example, who should be involved in decision-making about the ocean? Could relying on the removal of carbon dioxide from the oceans reduce the commitment of societies to reducing emissions through other means, such as reducing consumption, increasing efficiency and transformation of energy systems?

Who pays?

Finally, removing carbon dioxide from the oceans could be very costly.

For example, extracting and then adding rocks to reduce ocean acidity costs between US$60 and US$200 per ton of carbon dioxide removed. To put this into context, the world produced over 36 billion metric tons of carbon dioxide from energy alone in 2021.

Even macroalgae cultivation could cost tens of billions of dollars if done at the scale likely needed to make an impact.

These methods are more expensive than many actions that reduce emissions right now. For example, using solar panels to avoid carbon emissions can range from saving money to costing $50 per ton of carbon dioxide, while actions such as reducing methane emissions are even less expensive. But the damage caused by continued climate change has been estimated at hundreds of billions of dollars a year in the United States alone.

These costs raise more questions. For example, how much debt is it fair for future generations to bear and how should the costs be distributed globally to solve a global problem?

Removing carbon dioxide from the oceans could become a useful method of controlling global warming, but it should not be seen as a silver bullet, especially since there is no effective global system for taking decisions about the ocean.

Sarah Cooley, former researcher at the Woods Hole Oceanographic Institution and director of climate science at the Ocean Conservancy, contributed to this article.

This article is republished from The Conversation under a Creative Commons license. Read the original article here:

Elna M. Lemons