Why are atmospheric levels increasing?
Levels of several important greenhouse gases have increased by about 25 percent since large-scale industrialization began around 150 years ago. During the past 20 years, about three-quarters of human-made carbon dioxide emissions were from burning fossil fuels. Concentrations of carbon dioxide in the atmosphere are naturally regulated The movement of carbon between the atmosphere and the land and oceans is dominated by natural processes, such as plant photosynthesis. While these natural processes can absorb some of the net 6.1 billion metric tons of carbon dioxide emissions produced each year, an estimated 3.2 billion metric tons is added to the atmosphere annually. The Earths positive imbalance between emissions and absorption results in the continuing growth in greenhouse gases in the atmosphere.
