The Carbon Cycle

Virtually all scientists agree now that carbon dioxide gases generated by humans are causing the earth to become warmer. The carbon cycle can help us understand part of how this is happening and perhaps offer some solutions.

When we burn things (for example: fuel to heat our homes, gasoline to run our cars, or coal in power plants to produce electricity) we produce carbon dioxide gas. This enters the atmosphere and forms a sort of blanket around the earth. Sun can pass through the blanket and warm the earth. (This is usually a good thing—space is very cold.) The problem is that we now have extra carbon dioxide gas which is trapping too much heat. As a result, temperatures on earth are slowly rising.

We can use the carbon cycle to predict the influence changes may have on rising levels of carbon dioxide in the atmosphere. What would happen if we:
(Click question to uncover answer.)

• Burn fewer hydrocarbons (gasoline, coal, natural gas, etc.)?
  Answer: This would mean more carbon stays underground and less goes into the atmosphere.
• Burn more hydrocarbons?
  Answer: Right now we are releasing carbon dioxide much faster than plants can use it. Remember that photosynthesis needs light to take place. Overall, the amount of light doesn't change from year to year. Plants may grow faster but there is a limit. The result is more carbon dioxide in the atmosphere.
• Remove forests and grasslands?
  Answer: Fewer plants will mean less photosynthesis taking place. That means more CO₂ will stay in the atmosphere.
• Plant more forests and grasslands?
  Answer: This would remove more CO₂ from the atmosphere and help and create stronger ecosystems. However, there is a limit to how much we can plant. So it is unlikely that it would be able to remove all the CO₂ being produced today but it could remove a considerable amount.
• Add more organisms (fish, cows, humans, etc.)
  Answer: They would need more food and oxygen. This means they would eat the plants (or animals that ate the plants) and change oxygen to carbon dioxide. This would mean more carbon dioxide in the atmosphere.
• Create particles that block sunlight?
  Answer: This has been proposed as one way to stop the rising temperatures resulting from too much CO₂ in the atmosphere. The problem is that if you block the light plants won't be able to photosynthesize as much. That means more CO₂ stays in the atmosphere and there is less food for animals.