You’ve now learned how shortwave radiation emitted by the sun and longwave radiation emitted by carbon dioxide and water vapor contribute to the heating of the Earth’s surface. Over the past 120 years, scientists have observed that the Earth’s average global surface temperature has increased. At the same time, the atmospheric concentration of carbon dioxide has also increased. Take a closer look at how these changes may have occurred.
Everyday human activities release stored carbon from the solid earth into the atmosphere. You will be able to explain how human activities release stored carbon into the atmosphere.
Carbon is found in all living things and is also found in sediment, rocks, the ocean and the air we breathe.
Carbon is exchanged between the oceans, solid earth, biosphere and atmosphere through various natural processes.
The largest exchanges occur between the biosphere and atmosphere through photosynthesis and decomposition.
Living plants grow by absorbing carbon dioxide during photosynthesis. When plants die, bacteria decompose them and return carbon dioxide into the atmosphere.
For thousands of years, the processes that added and subtracted carbon dioxide from the atmosphere were in balance.
Since the Industrial Revolution, however, human society has become increasingly dependent upon machines that release carbon to the atmosphere.
Fossil fuels such as coal, gasoline, oil and natural gas contain high concentrations of carbon that have been stored in the solid earth for hundreds of millions of years.
When we burn fossil fuels for heat, transportation, and electricity, large quantities of carbon that would otherwise remain stored in the solid earth are released into the atmosphere in the form of carbon dioxide.
In summary, the dependence of human society on fossil fuels leads to a build up of carbon dioxide in the atmosphere.