Which human activity primarily contributes to increased levels of carbon dioxide?

The primary human activity that contributes to increased levels of carbon dioxide is burning fossil fuels. When fossil fuels such as coal, oil, and natural gas are combusted for energy, they release significant amounts of carbon dioxide into the atmosphere as a byproduct. This occurs in various sectors, including transportation, electricity generation, and industrial processes, making it the largest single source of anthropogenic (human-caused) CO2 emissions.

In contrast, activities like planting trees, using solar panels, and recycling generally contribute to reducing carbon emissions or capturing carbon. For example, trees absorb CO2 as they grow, while solar panels generate energy without emitting greenhouse gases. Recycling helps to save energy and materials, which can also lead to reduced emissions associated with producing new products from raw materials. Thus, these alternatives highlight the contrast between activities that increase carbon emissions and those that mitigate them.