From environmental viewpoint, the most important advantages of CFLs over incandescent lamps are reduction of green house gas emissions (especially CO2), decreasing calamite change rate and also decreasing mercury entry into the environment due to great reduction in energy use (A power plant will emit 10 mg of mercury to produce the electricity to run an incandescent bulb compared to
only 2.4 mg of mercury to run a CFL for the same time).