Annual Atmospheric CO2 Concentration (from 1959 to 2014)
Atmospheric carbon dioxide has a fundamental role for life on Earth since atmospheric carbon dioxide is essential for photosynthesis and photosynthesis is essential for life. Carbon dioxide, although present in trace amounts in our atmosphere, also plays an important role in regulation of surface temperature of our planet since it is a greenhouse gas due to interactions it can have by infrared radiation (it can absorb and emit infrared radiation at wavelengths of 4.26 µm due to asymmetric stretching vibrational mode and 14.99 µm due to bending vibrational mode).
From industrial revolution onwards, human activities especially the burning of fossil fuels and deforestation have caused considerable increase in atmospheric CO2 concentration which has contributed to global warming, a serious threat for continuity of life on Earth. In 50 years from 1965 to 2015, mean atmospheric CO2 concentration has increased by 25% from about 320 ppm to about 400 ppm. In this matter, the atmosphere hasn’t been alone; About 30%-40% of CO2 produced by human activities has been absorbed by oceans and resulted in ocean acidification threatening marine life.
Scientists and environmentalists have awoken societies about threats of global warming and ocean acidification. There have been many great efforts to stop or at least reduce the causes of these phenomena. In the case of atmospheric CO2, prohibition of deforestation and substitution of fossil fuels by other means from wind and solar energy to ethanol from plants have already been applied by many countries and there are many plans to make these efforts stronger. However, still there is accelerating increase in atmospheric CO2 concentration.