evidence: A vital component of the atmosphere, carbon dioxide (CO2) is released through natural processes (like volcanic eruptions) and through human activities, such as burning fossil fuels and deforestation. [...] Over the last century, burning of fossil fuels like coal and oil has increased the concentration of atmospheric carbon dioxide (CO2). This increase happens because the coal or oil burning process combines carbon with oxygen in the air to make CO2. To a lesser extent, clearing of land for agriculture, industry, and other human activities has increased concentrations of greenhouse gases. The industrial activities that our modern civilization depends upon have raised atmospheric carbon dioxide levels by nearly 50% since 17502. This increase is due to human activities, because scientists can see a distinctive isotopic fingerprint in the atmosphere.