Carbon dioxide is naturally present in the atmosphere as part of the Earth's carbon cycle. Human activities are altering the carbon cycle, by adding more CO2 to the atmosphere and by influencing the ability of natural sinks, like forests, to remove CO2 from the atmosphere. While CO2 emissions come from a variety of natural sources, human-related emissions are responsible for the increase that has occurred in the atmosphere since the industrial revolution.
Consider the graph above. Notice the trend in atmospheric carbon dioxide as recorded at recording stations over Antarctica. Hypothesize how the schematic of the carbon cycle might change if urbanization and deforestation continues unchecked.
Responses
A Both the carbon dioxide sinks and the carbon dioxide outputs will increase so the numbers should reach equilibrium.
B The photosynthesis carbon sink will decrease in gigatons; the carbon dioxide output due to combustion will increase.
C All of the carbon dioxide sinks will decrease in gigaton amounts; the carbon dioxide output due to combustion will increase
D Carbon dioxide outputs due to combustion of fossil fuels continues to increase; the rate of photosynthesis will also continue to increase to accommodate this.
C All of the carbon dioxide sinks will decrease in gigaton amounts; the carbon dioxide output due to combustion will increase
Unchecked urbanization and deforestation will lead to a decrease in carbon sinks such as forests, which absorb carbon dioxide through photosynthesis. This will result in a decrease in the amount of carbon dioxide removed from the atmosphere. At the same time, the continued burning of fossil fuels will result in an increase in carbon dioxide emissions, leading to a further increase in the amount of CO2 in the atmosphere. This will disrupt the balance of the carbon cycle and result in a continued increase in atmospheric CO2 levels.