Some processes add carbon dioxide to the atmosphere. There are other processes that absorb carbon dioxide from the atmosphere. The global
carbon cycle is a complicated interaction between processes that take
place on the land and processes that take place in the ocean.
Global Carbon Cycle Data
Process
Result in Atmosphere Change in Amount of Carbon
(billions of tons)
Burning of fossil fuels Adds carbon dioxide
+5.3
Agriculture
Adds carbon dioxide
+2.0
Photosynthesis Removes carbon dioxide
-120.0
Plant respiration Adds carbon dioxide
+50.0
Decomposition Adds carbon dioxide
+60.0
Ocean sink
Removes carbon dioxide
-110.0
Which change in the carbon cycle would have the greatest effect on the
amount of carbon dioxide in the atmosphere?
A. a 10% decrease in the burning of fossil fuels
B.
a 20% decrease in the number of photosynthetic organisms