The atmosphere is almost transparent to solar radiation and almost opaque to terrestrial radiation. This implies that in the mean the atmosphere cools while the earth's surface is heated. Convection in the lower atmosphere must therefore occur. The upward flux of energy associated with it is large in the equatorial regions and very small at high latitudes. Balance requirements then demand an energy flux from the equator to the poles, which is accomplished by large-scale atmospheric motions and ocean currents. This review concentrates on the nature of radiative transfer in the atmosphere, atmospheric motions that redistribute energy over the globe, and energy transfer in the convective boundary layer.