Greenhouse flux occurs due to the accumulation of greenhouse gases. Gases like carbon dioxide, methane, nitrous oxide trap radiations and absorb the light. The energy gets trapped in the earth and this causes a rise in temperature of the earth causing it to become warmer. This is called the greenhouse effect. Carbon dioxide has a maximum contribution in the greenhouse effect. It also maintains optimum earth temperature as less concentration of carbon dioxide will lead to loss of heat from earth causing a decrease in temperature. However, excess concentration of carbon dioxide can lead to an increase in earth's temperature causing global warming.
Hence, the statement given in the question is correct.
So, the correct answer is 'True'.