After reading the paragraph below, answer the questions that follow.
The graph below shows records of temperature (light gray line) and CO₂ (dark gray line) over the past 1,000 years. CO₂ is recorded in parts per million (ppm).

-Currently, atmospheric CO₂ levels are approximately 400 ppm. The annual mean growth rate in CO₂ is about 2 ppm/year. Assuming this trend continues, what would you predict the CO₂ level to be in 100 years?
A)100 ppm
B)200 ppm
C)600 ppm
D)1,000 ppm

Question

After reading the paragraph below, answer the questions that follow.
The graph below shows records of temperature (light gray line) and CO₂ (dark gray line) over the past 1,000 years. CO₂ is recorded in parts per million (ppm).
 
-Currently, atmospheric CO₂ levels are approximately 400 ppm. The annual mean growth rate in CO₂ is about 2 ppm/year. Assuming this trend continues, what would you predict the CO₂ level to be in 100 years?
A)100 ppm 
B)200 ppm 
C)600 ppm 
D)1,000 ppm

Quizplus · Accepted Answer

The graph shows that CO₂ levels have been steadily increasing over the past 1,000 years, with a more rapid increase in recent decades. The annual growth rate of 2 ppm/year indicates that in 100 years, CO₂ levels would increase by 200 ppm (2 ppm/year x 100 years). Therefore, the predicted CO₂ level in 100 years would be 400 ppm (current level) + 200 ppm (increase in 100 years) = 600 ppm. Choice C is the only option that matches this prediction.

After Reading the Paragraph Below, Answer the Questions That Follow