Chapter 25, Problem 1QC

Summary Introduction

To determine:

How human activities have affected ${\text{CO}}_2$ levels in the atmosphere as per graph given in Fig. $25.3$ and to determine another plausible alternative hypothesis for this.

Concept introduction:

Refer to Fig. $25.3$, the graph here shows the measurements of air samples in glacial ice from Law Dome, Antarctica. The curve shows atmospheric ${\text{CO}}_2$ concentration in ppm (parts per million) with respect to year. As glaciers gets covered with new layers of snow, there is a tiny space of air that lies between the molecules of snow. When this snow changes into ice, these spaces become sealed and preserve a minute sample of air at that time of ice formation.

Explanation of Solution

In the graph, it can be seen that there is a remarkable increase in ${\text{CO}}_2$ concentration at the time of industrial revolution. It can be a coincidence too, but it suggests that industrial revolution (human activities) has influenced the ${\text{CO}}_2$ levels in the atmosphere.

An alternative hypothesis is that, there are other possible factors or processes that might have contributed to the increase in the levels of ${\text{CO}}_2$ in the atmosphere. These processes include volcanic eruptions, global warming due to changes in solar radiation facilitating the increase in respiration of soil organic matter at higher latitudes, which in turn produce more ${\text{CO}}_2$.

Conclusion

${\text{CO}}_2$ levels are increasing in the atmosphere over time. Many processes have a role in it. Human activity is also one of the reasons in the increase of ${\text{CO}}_2$ concentration in the atmosphere.