The concentration of atmospheric carbon dioxide is currently decreasing due to human activities

No, the concentration is actually rising. We are burning too much fossil fuels (coal, oil and natural gas), and we are cutting down too many forests.

The concentration of atmospheric carbon dioxide is not currently decreasing due to human activities. It is increasing day by day.

Explanation:

   As human activities increase, the level of carbon dioxide is increasing steadily. This is due to the increase in human activity, as well as technological and industrial revolutions, which generally lead to increased emissions of this gas. With the advent of the industrial revolution came the increase in the emission of gases from the increase of industries, factories and the manufacture of motor vehicles.

  Even with the sophistication of the technology, to try to reduce this emission and create more sustainable cars, automotive, industries and factories, the emission continued, as the population continued to be born, grow, and thus increasing the numbers of people. With this increase, more and more manufacturing needed to be increased, thereby increasing the number of CO2 emissions.