The next most significant greenhouse gas is carbon dioxide. Higher concentrations of carbon dioxide and other greenhouse gases in the atmosphere will lead to increased trapping of infrared radiation. The lower atmosphere is likely to warm, changing weather and climate. The global carbon cycle remained fairly unchanged for the 800 years before the Industrial Revolution. The cycle has changed rapidly during the past 200 years.
Human activity is responsible for the rapid increase in atmospheric carbon dioxide concentrations.
The biggest global sources of carbon dioxide are regions of peak fossil fuel use. Atmospheric oxygen concentrations are declining slightly as carbon in fossil fuels and plants combines with oxygen during combustion to form carbon dioxide. Measurements of carbon isotopes, different forms of carbon, reveal extensive release of carbon from fossil fuels. Carbon sinks As plants grow, they photosynthesise, removing carbon dioxide from the atmosphere and converting it into organic compounds. Because of so-called carbon dioxide fertilisation, carbon uptake by most terrestrial plants will increase with increasing atmospheric carbon dioxide concentration.