Why are atmospheric levels of greenhouse gases increasing?
Concentrations of carbon dioxide in the atmosphere are naturally regulated by numerous processes collectively know as the “carbon cycle.” The movement (“flux”) 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 anthropogenic [made or generated by a human or caused by human activity] carbon dioxide emissions produced each year, an estimated 3.2 billion metric tons is added to the atmosphere annually. The Earth’s positive imbalance between emissions and absorption results in the continuing growth in greenhouse gases in the atmosphere. With the beginning of large-scale industrialization around 150 years ago, human activities have been dramatically adding to the carbon dioxide levels in the atmosphere. The burning of fossil fuels, such as coal and oil to power our cars, factories, businesses and homes, is increasing carbon dioxide beyond
