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.