The increasingly evident effects of the ongoing changes include acid de position by rain and other processes, corrosion of materials, urban smog and a thinning of the stratospheric ozone ( ) shield that protects the earth from harmful ultraviolet radiation. Atmospheric scientists expect also that the planet will soon warm rapidly. (Causing potentially dramatic climatic shifts) through enhancement of greenhouse heating the gases that absorb red radiation from the sun-warmed surface of the planet and then return the radiation to the earth.