On Wednesday, the federally funded National Academy of Sciences in the USA stated that they will be altering oceans to get C02 from the atmosphere and store it for the future.
The concept is explained in a 300-page, peer-reviewed report. The approaches proposed include using electrical currents on seawater and dumping iron in the ocean to encourage massive plankton blooms.
The main objective is carbon dioxide removal, also known as a form of geoengineering. It is very rare and expensive at the moment. They want to do it for $100 per ton of carbon stashed away.
Oceans play a significant role in absorbing carbon emissions but at the rate at which they are increasing, oceans will need to do more to keep global warming below the 1.5-degree-Celsius (2.7-degree-Fahrenheit) threshold outlined in international agreements.
The most common form of ocean geoengineering is iron fertilization, which would encourage plankton blooms to suck up carbon. Other techniques include seaweed cultivation and ecosystem restoration.
There are more as well. For example, inducing artificial upwelling and downwelling, so that the ocean water on the surface takes up more carbon, then siphons it down to the deep sea. Another approach is putting lime or other alkaline agents in the ocean. This would reduce ocean acidification, itself the result of a reaction when seawater comes in contact with carbon dioxide and allow oceans to take up more carbon pollution. The third is electrochemical carbon removal, pumping seawater through machinery that would draw carbon dioxide out of it and then safely store it away.
However, all these techniques have feasibility and regulatory issues. Disposing of tons of iron in the ocean can affect the marine ecosystem. Also, it is not sure if these approaches will be permanent. If the absorbed CO2 stays in the first 3,280 feet (1,000 meters) of the ocean, it will likely be put back in the atmosphere at some point, negating the benefits of sucking it up in the first place.
The report suggests that the Paris Agreement gives implicit support to carbon dioxide removal with several mentions of carbon sinks. But other treaties, like the Convention on Biological Diversity, have put a “de facto moratorium” on geoengineering the seas.
“None of these regulations, treaties, or laws were written with CDR in mind,” Scott Doney, an ocean researcher at the University of Virginia who led the report, said at a launch event for the report. “Moving forward, we’ll need to do a deeper dive” on research and regulations in tandem, he added.
However, these approaches are a necessity. The Intergovernmental Panel on Climate Change has estimated that the world will collectively need to remove about 10 gigatons of carbon dioxide from the atmosphere per year by midcentury to not overshoot the 1.5-degree-Celsius range of heating.
The report needs $125 million in investments over the next decade, with the biggest chunk at $50 million going to public outreach and engagement. A rigorous research program would cost an estimated $2.4 billion, or 0.3% of the just-passed annual Pentagon budget. The report calls for private funding with strict regulations.