Carbon Dioxide has Shown a Continual Increase Since Measurements Began

Multiple Choice

Carbon dioxide has shown a continual increase since measurements began about 1960.Why are scientists concerned about this rise?

A) CO₂ concentrations could become toxic if they increase even a small amount more.
B) An increase in atmospheric CO₂ means less in the oceans, where CO₂ is more needed.
C) An increase in CO₂ is positively correlated with rising temperatures, one aspect of climate change.
D) An increase in CO₂ is inversely correlated with fossil-fuel burning, which causes pollution.
E) An increase in atmospheric CO₂ is correlated with declining levels of photosynthesis.