AP BIOLOGY

Detailed explanation-1: -Burning fossil fuels, in combination with destruction of carbon sinks due to deforestation and other activities, has contributed to more and more carbon dioxide building up in the atmosphere – more than can be absorbed from existing carbon sinks such as forests.

Detailed explanation-2: -When fossil fuels are burned, they release large amounts of carbon dioxide, a greenhouse gas, into the air. Greenhouse gases trap heat in our atmosphere, causing global warming.

Detailed explanation-3: -Deforestation contributes up to 10% of the carbon dioxide emissions caused by human activity, according to 2013 figures from the Intergovernmental Panel on Climate Change.

Detailed explanation-4: -Carbon dioxide is added to the atmosphere by human activities. When hydrocarbon fuels (i.e. wood, coal, natural gas, gasoline, and oil) are burned, carbon dioxide is released. During combustion or burning, carbon from fossil fuels combine with oxygen in the air to form carbon dioxide and water vapor.

Detailed explanation-5: -Burning fossil fuels releases carbon dioxide gas to the atmosphere, and the ever-increasing global use of fossil fuels has caused the amount of carbon dioxide in the atmosphere to increase to a concentration that is higher than any time in the past 800, 000 years.