This article was about the intense farming practices that are powerful enough to increasingly alter Earths atmosphere. They have boosted the seasonal amplitude in carbon dioxide in the atmosphere to about 15 percent over the past five decades. Researchers from the University of Maryland have created a terrestrial carbon cycle model called VEGAS that has measured the carbon dioxide and found that it is increasing at a rate of 0.3 percent every year. The Vegas model has been able to do something that no other models have been able to do and that is measure the effect of changes in the intensity of farming methods. Other models have measured changes in land use from vegetation to cropland but none like the VEGAS.
Ocean Science Professor Ning Zeng, the lead developer of of VEGAS says that, “Changes in the way we manage the land can literally alter the breathing of the biosphere.” Since the 1950’s scientists have known that carbon dioxide levels in the atmosphere are at an annual low during the late summer and early fall in the northern hemisphere. During the spring and summer carbon dioxide levels fall as the hemispheres plants reach their maximum growth breathing in as much carbon dioxide as possible and releasing oxygen. In the fall, when the plants are dying out and decomposing and releasing stored carbon, carbon dioxide levels in the atmosphere rapidly increase.
Although reasons behind the drastic changes of the seasonal carbon dioxide cycle are hard to pin down, two factors are considered. 1. Because plants breathe in carbon dixoide, higher atmosphereic levels of the gas stimulate plant growth and therefore we have a sort of carbon dioxide fertilization effect. 2. Warming in the northern hemisphere makes plants grow better in cold regions.
Zeng says, “between 1961 and 2010, the amount of land planted with major crops grew by 20 percent, but crop production tripled. The combination of factors known as the Green Revolution–improved irrigation, increased use of manufactured fertilizer, and higher-yield strains of corn, wheat, rice and other crops–must have led not only to increased crop productivity, but also to increases in plants’ seasonal growth and decay and the amount of carbon dioxide they release to the atmosphere, he reasoned.”
Their goal was to simply represent the intensification of agriculture in a model of the carbon cycle, and thats what they did.