Since about 1750, human activity has increased the concentration of carbon dioxide and other greenhouse gases. Measured atmospheric concentrations of carbon dioxide are currently 100 ppm higher than pre-industrial levels. Which of these is NOT a human impact on the carbon cycle?
Responses
A Volcanoes have released significant carbon emissions with eruptions.Volcanoes have released significant carbon emissions with eruptions.
B Burning fossil fuels transfers carbon from the geosphere into the atmosphere.Burning fossil fuels transfers carbon from the geosphere into the atmosphere.
C Increased CO2 emissions from fossil fuel usage has increased ocean CO2 levels and led to ocean acidification.Increased CO 2 emissions from fossil fuel usage has increased ocean CO 2 levels and led to ocean acidification.
D Deforestation and land use changes have increased atmospheric CO2 by decreasing carbon stored in and used by plants in the process of photosynthesis.
1 answer
A. Volcanoes have released significant carbon emissions with eruptions.