FIGURE 63.12 Global change feedback systems. (a) Temperature and CO2 represent a positive feedback system. When the concentration of CO2 increases in the atmosphere, it can cause global temperatures to increase. This in turn can cause more rapid decomposition, thereby releasing even more CO2 into the atmosphere. (b) Carbon dioxide and producers represent a negative feedback system. Increased CO2 in the atmosphere from anthropogenic sources can be partially removed by increased photosynthesis by producers.