Pulling CO2 From The Sea

This clever idea starts with the knowledge that the ocean naturally holds about 150 times more carbon dioxide than the air.

Aerial view of ocean waves crashing on the shore

All around the world, researchers and scientists are looking for effective and economical ways to pull CO2 out of the air to mitigate the effects of climate change. There are many promising 'carbon capture' solutions out there but the amount of CO2 that needs to be withdrawn is substantial and the process of pulling it out of the air is energy intensive.

A UCLA research team has proposed that the solution might be in the ocean.

The oceans and the atmosphere work in a constant state of equilibrium, and the earth’s seas have countless plant-like organisms called phytoplankton that absorb carbon dioxide through photosynthesis. The team from UCLA proposes that instead of drawing carbon dioxide out of the air, we pull it from the sea, thus giving it room to absorb even more.

The proposed system would involve a flow reactor that takes in seawater, runs it through a mesh that has an electric charge running through it at a specific frequency. This creates a chemical reaction with the naturally occurring magnesium and calcium in the seawater that combines them with the carbon to form, essentially, limestone and CO2-free water that is returned to the ocean. The only other byproduct of this system would be hydrogen which is a clean fuel. The ocean would then do what it does and absorb more carbon dioxide out of the atmosphere.

The team emphasized the “single-step” process of this system, as other technological solutions require multiple concentration processes to turn carbon dioxide into stone. The UCLA system does it all in one step while pulling CO2 out of the ocean.

The system would need to be developed and expanded to a very large scale in order to remove carbon dioxide in an effective way. “Managing and mitigating carbon dioxide is foremost an economic challenge,” said Gaurav Sant, director of the UCLA Institute for Carbon Management. The team still believes that their system, even at smaller scales, is a new step in the carbon capturing journey and will be an invaluable tool for this endeavour.