Consider the following activities:
1. Spreading finely ground basalt rock on farmlands extensively
2. Increasing the alkalinity of oceans by adding lime
3. Capturing carbon dioxide released by various industries and pumping into abandoned subterranean mines in the form of carbonated waters
How many of the above activities are often considered and discussed for carbon capture and sequestration?
Explanation
Statement 1 — Correct: Spreading finely ground silicate minerals (such as basalt rock) over agricultural farmlands—known as Enhanced Rock Weathering (ERW)—accelerates natural chemical weathering reactions that convert atmospheric CO_2 into stable aqueous bicarbonate ions.
Statement 2 — Correct: Adding alkaline substances such as lime (CaO or Ca(OH)_2) to ocean surfaces—known as Ocean Alkalinity Enhancement (OAE)—increases seawater pH and alkalinity, enhancing the ocean’s chemical capacity to draw down and sequester dissolved inorganic carbon.
Statement 3 — Correct: Capturing industrial CO_2 emissions, dissolving them in water under high pressure to create carbonated fluid, and injecting the solution into abandoned subterranean mines or basalts leads to in situ mineral carbonation, trapping carbon as stable solid carbonate rock.
Therefore, all three are recognized methods for carbon dioxide removal and sequestration.