Energy > Climate Change
August 2021
The power of carbon dioxide
This article is the sixth in a series focused on the causes and consequences of a warming planet
Carbon dioxide has been a driver of the world’s climate for millions of years. It is a greenhouse gas that absorbs heat radiated upward from the Earth and holds the heat in the lower atmosphere. So, carbon dioxide in the atmosphere helps to warm the Earth to a comfortable temperature.
A problem arises when too much carbon dioxide is in the atmosphere. The Earth gets warmer than we want. We cannot blame this on Mother Nature. Left to nature there would be just the right amount of carbon dioxide in the atmosphere. Through our activities, the amount of carbon dioxide in the atmosphere has expanded, causing the Earth’s temperature to rise which in turn causes the climate to change. For example, each us contributes about 16 tons of carbon dioxide to the atmosphere each year.
Carbon dioxide is the most prevalent long-lived greenhouse gas. Carbon dioxide emissions come from decomposed plants and animals stored deep in the earth. The carbon is brought to the Earth’s surface where it is emitted into the atmosphere through the process of burning. The carbon can be in a solid form (coal), liquid form (crude oil), or gaseous form (natural gas).
While the pre-industrial atmospheric carbon dioxide concentration was about 280 parts per million (ppm), current measurements show the concentration is 416 ppm. The previous high in carbon dioxide during the last 800,000 years was 300 ppm. With strong economic growth and no limits on carbon dioxide emissions, scientists predict atmospheric concentration could reach 600 ppm by 2050. In addition, once carbon dioxide is emitted, it can stay in the atmosphere for centuries.
Carbon dioxide has an important natural cycle that does not add to the atmospheric concentration and is critical for plant life on earth. Crops, trees and other plants use the process of photosynthesis to grow and flourish. Photosynthesis takes carbon dioxide from the air and uses it to build the plant. When the plants die and decompose, the carbon dioxide is released back into the atmosphere.
So, the flowers in your back yard take carbon dioxide out of the air in the spring and summer when they grow and release it back into the atmosphere when they die in the fall. But this annual fluctuation should not be confused with the long-term upward trend in atmospheric carbon dioxide over many years.
See the Ag Decision Maker website for more from this series.
Don Hofstrand, retired extension agricultural business specialist, agdm@iastate.edu
Reviewed by Dr. Eugene Takle, retired professor emeritus Iowa State University
