In the past 50 years, earth has seen a deepened breathing pattern. This pattern is the inhale and exhale of carbon dioxide by the plants on earth, each year, in a seasonal cycle.
This seasonal breathing pattern for terrestrial plants was captured by NASA. They have released a video for the same this week. It shows the rise and fall of CO2 levels as well as CO2's movement across the hemisphere over the course of 2006.
There are two teams of researchers who are working independently on this research. They have largely suggested that across the northern hemisphere, farming is responsible for 20 to 50% of the long-term increases in the amount of CO2 that is taken up during the growing season and in the amount given back during the dormant season.
UW-Madison's Chris Kucharik, a co-author of one of the study and professor in the College of Agricultural and Life Sciences Department of Agronomy and the Nelson Institute for Environmental Studies said, "This is another piece of evidence suggesting that when we (humans) do things at a large scale, we have the ability to greatly influence the composition of the atmosphere".
Both the teams have noted that farming's influence has come not from large increases in acres planted but from enormous increases in farm productivity. One of these studies suggests that rising levels of CO2 in the atmosphere is because of the use of fertilizers, improved crop breeds and better irrigation that has eventually led to increased farm productivity. This increase has been more influential than the longer growing seasons that have come with global warming.
Similar results were generated by a research team last year. This team was led by scientists from the Scripps Institution of Oceanography in La Jolla, California. The research too reported that there is a general trend in CO2 exchanges between plants and the atmosphere.