Question

800,000 bce to 2015 ce (graph: carbon dioxide concentration (ppm) vs year (negative values = bce)); 1950 to 2015 ce (graph: carbon dioxide concentration (ppm) vs year); students wonder about the causes and effects of this change. which two questions best clarify the cause and effects of the change in carbon dioxide levels? a. did light intensity at earth’s surface increase after 1950? b. did global temperature increase in 2015 compared to 1950? c. did the wind speed at the equator consistently increase after 1950? d. did fossil fuel use increase in 1950 compared to the previous century? e. did the oxygen concentration in earth’s atmosphere begin to decrease in 1950?

Explanation:

To clarify the cause and effects of CO₂ level change:

• Option B: Global temperature and CO₂ are linked (greenhouse effect), so checking temperature change (effect) is relevant.
• Option D: Fossil fuel use releases CO₂, so checking its increase (cause) is relevant.
• Options A (light intensity), C (wind speed), and E (oxygen concentration) are not directly tied to CO₂’s cause/effect.

Answer:

B. Did global temperature increase in 2015 compared to 1950?
D. Did fossil fuel use increase in 1950 compared to the previous century?