Carbon dioxide


Carbon dioxide is a compound in which two oxygen atoms are connected to a carbon atom. At normal temperatures it is a colourless gas that exists naturally in the Earth’s atmosphere. The air that we breathe has about 0.03% of carbon dioxide in it.

Carbon dioxide is an important part of the carbon cycle and essential for life on Earth.  Without it temperatures on our planet would be very low.

Plants use the sunlight and take up the CO2 in the atmosphere to produce energy and oxygen. This process is called photosynthesis.

The gas is also produced when fossil fuels are burned. Carbon dioxide that has been stored for millions of years in coal, oil and natural gas is set free. Living creatures produce carbon dioxide when they breathe out. It is emitted from volcanoes and hot springs. Deforestation sets carbon that is stored in trees free.

Carbon dioxide is an important greenhouse gas. Light that enters the atmosphere it is converted to heat. Higher amounts of CO2 make the atmosphere denser and keep it from getting out. CO2 is a gas that is highly responsible for global warming. Since the Industrial Revolution of the 1800s the amount of CO2 in our atmosphere has risen by 40%.

Throughout the centuries carbon dioxide has been in balance. Now more carbon dioxide is being produced than can be absorbed by nature.



Uses of Carbon Dioxide

Carbon dioxide is used in various industries to produce food, chemicals and oil products. It is especially common as a food additive and is added to beverages to give fizz to sparkling wine and water. It is also responsible for a beer’s foam.

As a pressurized gas carbon dioxide is used in fire extinguishers because it does not burn. Put in cartridges it can be used to inflate bike tires. In its solid form CO2 is called dry ice. It is used for cooling fresh food or ice cream. Liquid carbon dioxide is needed to remove caffeine from coffee


Carbon dioxide in oceans

Oceans are carbon sinks. They absorb more than 25% of all the carbon dioxide that people emit into the atmosphere. As a result, the ocean’s water is becoming more acidic. This change affects the food chain and all sea organisms.


Carbon dioxide poisoning

Although carbon dioxide is not poisonous in normal amounts it can kill you if there is more than 10% in the air. High concentrations can lead to dizziness, bad sight, breathing problems as well as a high blood pressure and an increased heart beat. High levels of CO2 occur when there is not enough fresh air in a room.



Related Topics



  • absorb = take in
  • acidic = with a lot of acid in it
  • although = while
  • amount = level
  • beat = strike
  • beverage = drink
  • breathe = take air into our lungs
  • carbon = chemical that exists in pure form as diamonds; it is also in coal and graphite
  • cartridge = a small container that you put inside a machine to make it work
  • century = a period of a hundred years
  • common = widespread
  • compound = substance that has atoms from two or more elements
  • connect = link, bind together
  • convert = change
  • creature = living things
  • cycle = events that happen over and over again, in the same order
  • deforestation = cutting or burning down trees
  • dense = thick
  • dizziness = feeling unable to stand steadily
  • emit = send out
  • essential = needed to survive
  • fire extinguisher = metal container with water or chemicals in it ; used to stop small fires
  • fizz = bubbles that appear in drinks
  • foam = mass of white bubbles on the top of a liquid
  • food additive = substance that is put into food to make it better or last longer
  • food chain = all the animals and plants that live together; a smaller plant or animal is eaten up by a larger one  etc..
  • fossil fuel = energy in the form of coal, oil , wood and natural gas; it was produced by dead animals and plants millions of years ago
  • greenhouse gas = gas that traps heat in the atmosphere and is the cause of global warming
  • highly responsible = the biggest cause of
  • hot spring = place where hot water comes up naturally to the surface
  • in balance = exactly the right amount; not too much and not too little
  • increase = to go up
  • inflate = pump air into
  • liquid = fluid, watery
  • occur = happen
  • poisonous = deadly
  • pressurized = to put under pressure
  • process = action
  • remove = take away
  • sink = here: container that is used for storing things
  • solid = hard, not a gas or a liquid
  • store = keep for later use
  • take up = absorb, take in
  • throughout = in all of
  • various = different kinds of