6. Are there other ways to use CO2?

There are a number of uses for CO2. It is used as a supplement to food products (carbonated drinks and popping candies are two examples). CO2 can also be used in greenhouses and other plant growing operations, to increase crop production. Solid CO2 (better known as dry ice) is used to keep food and other items frozen – CO2 becomes asolid at temperatures less than minus 78°C.

However, CO2 used for these purposes must be 100% pure – particularly if it is being put into foods that we eat. The CO2 being used for injection into the Weyburn and Midale oilfields contains small amounts of other compounds that mean it cannot be used for food production.

In the Weyburn oilfield, CO2 is used as a thinner that mixes with the oil to increase production. The CO2 is "miscible," meaning that it can mix and absorb into the oil. This causes the oil to expand out of cracks and pores in the oilfield. When the oil expands, more of it can flow to the production wells. Oil production in the Weyburn oilfield has almost tripled because of the injection of CO2.

Figure 3. In the 350,000 years prior to human industrial activity, CO2 readings in the atmosphere never went above 300 parts per million (ppm). Since the industrial revolution (18th century) and at an increasing rate into the 21st century, CO2 in the atmopshere has surpassed 400 ppm and continues to climb at an increasing rate. Since 1950 CO2 in the atmosphere has gone up by 30%.