Students learn that carbon dioxide is a greenhouse gas that contributes to climate change. They want to identify the sources of carbon dioxide emissions in order to make a plan to reduce their town's impact on climate change.

Question

Which two processes contributed most to the changes in carbon dioxide concentrations since 1985?

A. respiration of a growing population

B. transportation of goods and people

C. manufacturing of materials like cement

D. development of renewable energy sources

E. expansion of public transportation services

Answer 1

The two processes that contributed most to the changes in carbon dioxide concentrations since 1985 are:

B. transportation of goods and people

C. manufacturing of materials like cement

Transportation and manufacturing, particularly of materials like cement, are significant sources of carbon dioxide emissions due to the reliance on fossil fuels and industrial processes involved. In contrast, options D and E involve efforts to reduce emissions, and A (respiration) generally does not lead to a significant increase in atmospheric CO2 equivalent to the other processes listed.