The option that is NOT a human impact on the carbon cycle is:
A) Volcanoes have released significant carbon emissions with eruptions.
Here's why:
1. Volcanoes do release carbon dioxide when they erupt, but the amount they release is relatively small compared to the emissions from human activities such as burning fossil fuels.
2. Human activities, like burning fossil fuels and deforestation, have significantly increased the levels of carbon dioxide in the atmosphere, affecting the carbon cycle on a larger scale.
3. While volcanic eruptions can contribute to short-term fluctuations in carbon dioxide levels, the long-term and substantial increase in carbon dioxide concentrations since 1750 is primarily due to human activities.
By understanding the differences between natural processes like volcanic eruptions and human-induced activities in impacting the carbon cycle, we can see why the option about volcanoes is not a human impact on carbon dioxide levels.
