Final answer:
The increase in atmospheric carbon dioxide from 1960 to 2008 is largely due to human activities, including burning of fossil fuels and deforestation. These activities release more carbon dioxide into the atmosphere, increasing its concentration.
Step-by-step explanation:
The increase in the percentage of carbon dioxide in the atmosphere from 1960 to 2008 can be primarily attributed to human activities. Since the industrial revolution, humans have been burning fossil fuels (such as coal, oil, and natural gas) at an increasing rate, which releases large amounts of carbon dioxide into the atmosphere. The process of deforestation, where trees that absorb carbon dioxide are cut down and often burned releasing more of this gas, also contributes significantly to the problem. The increase from 0.032% to 0.038% may seem small but given the vast size of our atmosphere, it represents a large quantity of additional carbon dioxide.
Learn more about Greenhouse Gases