Can Marine Geoengineering Really Stop Climate Change? Or is it Just Dystopian Science Fiction?

Ocean alkalinity enhancement, zero-point energy accumulators, cortical stacks, artificial ocean upwelling... if you can believe it, not all of these are from the science fiction world.

The ones that are not from movies, books, and comics are geoengineering ideas promoted by billionaires who claim they want to save the planet. Geoengineering is a broad category of activities that deliberately manipulate the Earth’s atmosphere, oceans, and soils to cool the Earth. And somehow, these ideas are just as dystopian as a grape-sized machine we embed into our skulls so we can “back up” our consciousness and take on new bodies (aka a cortical stack).

Geoengineering intervenes in Earth’s complex systems; not only can we not control these processes, but we also can’t accurately predict the outcomes of changes to those systems. Tech companies and entrepreneurs are behind most of these projects. They claim to be saving the planet, but are really just helping fossil fuel companies cover themselves while they continue polluting.

What is marine geoengineering?

Marine geoengineering specifically refers to attempts to manipulate the Earth’s oceans to address climate change. Most marine geoengineering proposals aim to take carbon dioxide (CO2) from the atmosphere and store it in the ocean.

Take ocean iron fertilization – an idea that calls for dumping mass quantities of iron into the ocean to encourage phytoplankton to grow. These microorganisms consume CO2 through photosynthesis and, when they die, sink to the ocean floor, contributing to long-term CO2 storage. All it would take for this to work is a measly 5,500 chemical tankers doing this across over 20% of the world’s oceans, around 15x per year! Please note the sarcasm here.

Another proposition is ocean alkalinity enhancement, which involves dumping alkaline substances such as limestone into the ocean. The limestone would cause a reaction that makes it pull more CO2 from the atmosphere, which is then stored in the ocean. But to get the limestone, we would first need to mine it, process it, and ship it around the world. Even with our current infrastructure, every large cargo ship in the world would need to dedicate its entire cargo capacity to limestone to do this. This process would likely emit more CO2 than it would capture.

If these approaches aren’t wild enough, dig into artificial ocean upwelling. In the ocean, deeper water is colder and more nutrient-rich due to the accumulation of decaying sea life. Naturally, this water is pulled upwards by currents and wind, cooling surface waters and providing critical nutrients. Marine geoengineers want to mimic this process by installing over 180 million giant pumps and tubes that reach 3,000 feet (about twice the height of the Empire State Building) deep into polar waters to pump cold, nutrient-rich water to the surface. This would, in theory, cool surface temperatures globally, which would cause land plants to draw down more CO2.

Marine geoengineering is unsafe and unproven

There are several gaps in these ambitious plans, including a lack of evidence that these would work or be safe. Because these technologies would be deployed at a large scale, we aren’t able to test or accurately predict the outcomes of each. And once we’ve deployed something, it’s nearly impossible to accurately measure the carbon captured because of the ocean’s large and dynamic functions. Further, deploying any of these at a large scale would require massive, coordinated global efforts, significant investments, and ongoing maintenance.

Models are already showing these efforts may not be as fruitful as promised. Even when conducted continuously and at large scales, research shows that marine carbon dioxide removal approaches would have limited effectiveness (less than 8% of warming) or severe environmental impacts.

Benjamin Day, Senior Campaigner at Friends of the Earth US, said:

“To have a meaningful impact on the climate, marine geoengineering techniques would have to manipulate 10 percent, 20 percent, or even more of the Earth’s oceans. Many of these approaches would use global ecological disruption as the very mechanism for changing the climate, or manipulate ocean chemistry on an unprecedented scale, with cascading impacts for marine ecosystems and the coastal communities who rely on them. Given the stakes, we must hit the brakes on the rush to develop and deploy marine geoengineering technologies.”

Huge risks and catastrophic consequences

The risks of investing in marine geoengineering are huge. Experiments at this scale could harm ocean and marine life by creating oxygen-depleted zones, harm fish and crustacean stocks by affecting the base of the marine food chain, or by making the ocean’s surface too alkaline for most marine life. Drastic changes in ocean alkalinity or temperature could disrupt ocean ecosystems and undermine the ocean’s existing ability to take up CO2. All of these would have catastrophic consequences for the over 3 billion people who rely on the ocean for their livelihoods.

Renewable energy: the real climate solution

These geoengineering projects give fossil fuel corporations a cover, so they can continue pushing fossil fuels while the public believes they are working to save the planet. The false sense of time and security this creates placates the public and undermines ongoing mitigation efforts. And this is where the carbon offset credits come in. With the immediate pressure off, corporations can invest in geoengineering technologies by buying “carbon offset credits.” This allows them to claim “net zero emissions,” freeing them from the responsibility of actually reducing emissions while allowing them to appear they are doing so, as they happily continue to pollute our planet.

At Friends of the Earth, we are proud to be part of the growing, global movement to stop geoengineering, alongside other researchers, academics, and Indigenous Peoples around the world. This technology is unjust, unproven, and not worth the risk.

Right now, our efforts are better directed at a real, proven solution to the climate crisis – renewable energy. And for the near future, anything else is pure science fiction.

You can learn more about geoengineering and our work on this and more at https://foe.org/projects/geoengineering/