But if CO2 is so harmful, why is it deliberately injected into so many of our drinks?

'Carbon Trees' Would Suck CO2 Out of Air and Into Your Soda | OnEarth Magazine

New devices could capture greenhouse gas and provide CO2 for commercial uses, all in one pop

Carbon dioxide is one of the most plentiful gases in the atmosphere, but when soda makers want to inject the fizz into their sweet-tasting drinks, they often have to pay through the nose for it. Many bottlers buy CO2 that was created as a byproduct of industrial processes, paying up to $300 per ton for the gas.

Atmosphere of Earth - Wikipedia, the free encyclopedia

Dry air contains roughly (by volume) 78.09% nitrogen, 20.95% oxygen, 0.93% argon, 0.039% carbon dioxide, and small amounts of other gases. Air also contains a variable amount of water vapor, on average around 1%.

The Obama Team's Drink of Choice? Coke, Not Pepsi - TIME

Several senior Administration officials are committed cola drinkers, and without fail they spend their days sipping from a can of Diet Coke, a product of Pepsi's chief competitor, Coca-Cola. On Monday, as members of Congress and key lobbyists filed into a briefing room for the final event of a daylong fiscal summit, they were greeted with an ice chest full of complimentary Diet Coke, not Diet Pepsi. (Montana Democratic Senator Max Baucus was one of many to grab a can.) Hours earlier, at a breakout session with members of Congress in the Indian Treaty Room, Office of Management and Budget Director Peter Orszag handled not one, but two cans of Diet Coke during the nearly two-hour session. Larry Summers, Obama's top economic adviser, rarely walks anywhere in the White House complex without a can of Diet Coke in his hand.