Final answer:
Burning fossil fuels is the human activity that has caused the greatest increase in atmospheric CO2 concentrations.
Step-by-step explanation:
The human activity that has caused the greatest increase in concentrations of atmospheric CO2 is burning fossil fuels. When fossil fuels such as coal, oil, and natural gas are burned for energy, carbon dioxide (CO2) is released into the atmosphere. This is due to the carbon content in these fuels, which combines with oxygen during the combustion process. The continuous burning of fossil fuels for transportation, electricity generation, and industrial processes has contributed significantly to the rising levels of CO2 in the atmosphere.
For example, the combustion of gasoline in cars releases CO2 as a byproduct, contributing to increased atmospheric CO2 levels. The burning of coal for power generation also emits large amounts of CO2. These activities have led to the phenomenon known as the greenhouse effect, where the increased concentration of CO2 in the atmosphere traps heat and causes a rise in global temperatures.
While other human activities like planting trees and recycling aluminum can help mitigate the effects of CO2 emissions, they do not contribute as significantly to the increase in atmospheric CO2 concentrations as burning fossil fuels does.
Learn more about The impact of human activities on atmospheric CO2 concentrations