May 29, 2015

Carbon Dioxide Facts

Carbon Dioxide gets a bad rap from the press, but it is natural and essential to life. CO2 is a colorless, odorless, non-toxic gas and it is not a pollutant. Trying to control CO2 by regulation is trying to regulate and control nature. Without CO2, plants die off and without plant life the earth's biological food chain would be terminally broken.

Plants require carbon dioxide to conduct photosynthesis. Greenhouses enrich their atmospheres with additional CO2 to sustain and increase plant growth. Plants can grow as much as 50 percent faster in concentrations of 1,000 ppm CO2 when compared with ambient conditions. If carbon dioxide is increasing so much around the globe, it would be logical that plants and trees would be growing faster than they previously did, but they are not.

CO2 is reduced by photosynthesis of plants. A photosynthesis-related drop (by a factor less than two) in carbon dioxide concentration in a greenhouse compartment would kill green plants, or completely stop their growth. Increased atmospheric CO2 concentrations result in fewer stomata developing on plants, which leads to reduced water usage and increased water-use efficiency.

Deforestation for agriculture is just replacing one type of vegetation with another. Both trees and plants reduce CO2.

Photosynthesis by phytoplankton consumes dissolved CO2 in the upper ocean and promotes the absorption of CO2 from the atmosphere. Photosynthesis uses carbon dioxide and water to produce sugars from which other organic compounds can be constructed, and oxygen is produced as a by-product. Sea urchins convert carbon dioxide into raw material for their shells.

Carbon dioxide dissolves in the ocean to form carbonic acid (H2CO3), bicarbonate (HCO3) and carbonate (CO32). There is about fifty times as much carbon dissolved in the sea water of the oceans as exists in the atmosphere. The oceans act as an enormous carbon sink, and take up about 30% of the total released into the atmosphere.

In medicine, up to 5% carbon dioxide (130 times atmospheric concentration) is added to oxygen for stimulation of breathing after apnea and to stabilize the O2/CO2 balance in blood.

Liquid and solid carbon dioxide are important refrigerants, especially in the food industry, where they are employed during the transportation and storage of frozen foods. Solid carbon dioxide, dry ice is used for small shipments where refrigeration equipment is not practical.

Carbon dioxide is used in enhanced oil recovery where it is injected into or adjacent to producing oil wells, when it becomes miscible (mixed) with the oil. It acts as both a pressurizing agent and, when dissolved into the underground crude oil, significantly reduces its viscosity, and changes surface chemistry enabling the oil to flow faster.

Carbon dioxide is used to keep the pH level from rising in swimming pools.

Atmospheric concentrations of carbon dioxide fluctuate slightly with the change of the seasons. Concentrations of carbon dioxide fall during the Northern Hemisphere spring and summer as plants consume it, and rise during the northern autumn and winter as plants go dormant or die.

Up to 40% of the gas emitted by some volcanoes during eruptions is carbon dioxide.

Various proxies and modeling suggests larger variations in past times. 500 million years ago CO2 levels were likely 10 times higher than now.

Take a deep breath, exhale and out comes carbon dioxide. All the carbon in our body comes either directly or indirectly from plants, which recently took it out of the air. When we breathe out, all the carbon dioxide we exhale has already been accounted for. We are simply returning to the air the same carbon that was there to begin with, so humans are carbon neutral.

Incidentally, during 2009, energy-related CO2 emissions in the US had their largest absolute and percentage decline, seven percent (which followed a three percent drop in 2008), since the start of US Energy Information Administration comprehensive record of annual energy data that began in 1949.