Sunday, July 29, 2018

Carbon Capture: Ocean Acidification Remediation

The ocean has absorbed approximately a third of the extra carbon released since the industrial age. When carbon dioxide is absorbed by seawater it becomes carbonic acid, leading to the gradual acidification of the oceans.

There are several methods proposed by which the carbon stored in the ocean can be more rapidly sequestered, reducing carbonic acid levels (though the ocean would promptly take up more carbon from the atmosphere):

  • alkalinization: to counteract the carbonic acid by adding huge quantities of alkalines to the ocean, such as bicarbonate. Quite usefully, bicarbonate is one of the bi-products of large scale enhanced weathering, which also appears to be quite promising as a mechanism to remove carbon from air.
  • fertilization: the carbonization of the oceans could be addressed by encouraging phytoplankton to grow, which would take up carbon from the water. Different parts of the ocean contain phosphorous, nitrogen, and iron in differing amounts. There are large dead zones in the ocean where plankton and algae grow is stalled due to lack of the needed minerals, not lack of food energy to support them. By adding these three minerals in the correct ratio, phytoplankton will be enabled to consume more carbon.
  • circulation: encourage movement of acidic water from near the surface to the deeper ocean where mineralization processes can absorb it. Ocean-based Climate Solutions, Inc has a description of the mechanism to do this.

The main issue with these ideas is that they are not self-funding, they do not produce an output which can be used to generate revenue to continue the effort. These kinds of projects would depend on massive external support, as by governments or the (very) wealthy.