“Seawater naturally absorbs about a third of the CO2 emitted into the atmosphere, making the water more acidic and causing it to dissolve calcium carbonate, which is abundant in the ocean. ‘Calcium carbonate is what coral skeletons, shells and all the things that make up most of the sediments at the bottom of the ocean are made of,’ said Adkins.

The dissolved calcium carbonate then reacts with the CO2 in the water to form bicarbonate salts, locking the CO2 away. ‘There are already 38,000 gigatons (38 trillion tons) of bicarbonate in the ocean right now,’ Adkins added.

Calcarea wants to mimic this natural process by funneling the ship’s exhaust fumes to a reactor in the ship’s hull, where the fumes are vigorously mixed with seawater and limestone — a type of rock mostly made of calcium carbonate, and a common ingredient in concrete. The CO2 in the exhaust fumes reacts with the mixture, creating salty water that locks the CO2 away in the form of bicarbonate salts. Adkins says that with a full-scale reactor, he aims to capture and store about half of a ship’s CO2 emissions.

In the natural world, the reaction takes over 10,000 years, according to Adkins, but in Calcarea’s reactors it takes about a minute, he said. This is achieved by bringing the CO2 and the limestone into intimate contact with each other.

The salty water that’s created is simply released into the ocean, where it poses no threat to marine life or to the seawater’s chemical balance, according to Adkins. He added that the company is also looking into adding a pre-filter to the system to get rid of other pollutants from the exhaust that might get mixed into the water, such as particulates and unburnt fuel, as well as other contaminants.”

From CNN.