Each year during the spring season the carbon dioxide levels in the atmosphere reaches to its minimum. The reason is that during this time the plants get new leaves and they grow maximum. The more the leaves sprout, the more the leaves grow, the more photosynthesis will take place which means enhanced intake of atmospheric CO2 to produce food. This reflects as a dip in the atmospheric concentration of CO2.
During the harsh winters and fall the plants shed their leaves. It is this time that the global CO2 level reaches to its annual high.
As per the NASA’s observations based on the Atmospheric Infrared Sounder (AIRS) instrument, the annual minimum CO2 level across the globe at all locations has crossed 400 ppm mark which is considered as the landmark. Through AIRS instrument it is possible to map CO2 levels in the troposphere on a global scale.
This much high level of atmospheric carbon dioxide makes the climate change an irreversible process.
How much increase in the carbon dioxide levels in the atmosphere have been observed during the past 150 years?
It is important to note that prior to industrial revolution, the carbon dioxide levels in the atmosphere was stable at around 280 ppm. By 1961, the CO2 level in the atmosphere started increasing at the rate of 2 ppm per year as per the NASA’s monitoring station at the summit of Hawaii’s Mauna Loa volcano. In 2005, the CO2 concentrations reached as high as 380 ppm. The annual average global CO2 level crossed 400 ppm mark in May 2013, and now the annual minimum is also above this mark.