Adding lime to oceans could sequester millions of tons of CO2
July 21, 2008 by Jozef Winter
Since the world’s oceans are by far the largest carbon sink on the planet, they’ve been paid a lot of attention in recent years, not only as a gauge to measure climate change but also as possible repositories for excess CO2 currently floating in the atmosphere. Geo-engineering projects have been underway to increase the amount of carbon absorbed and sequestered by these waters, the most commonly known of which is iron-fertilization, a process where iron filings are dumped into the ocean to promote algal growth which absorbs CO2, dies, and then sinks to the ocean floor. That’s the idea anyway, and one which has not had a lot of success. A new method, however, shows some promise, though we will reserve our final thoughts on the matter once we see some more data.
The process involves using lime, obtained from burning limestone as pictured above, and releasing it into the oceans. Adding the lime, which is chemically calcium hydroxide, increases the alkalinity of the seawater. Since higher ocean acidity impedes the absorption of CO2, bringing it back to a more alkaline state is ideal. Shell, the Dutch oil multinational, is apparently impressed with the idea and has committed funding to determine the economic feasibility of the project, which is being developed under open source.
