What type of radiation does Earth emit?

Earth emits mostly Longwave radiation. Solar energy enters our atmosphere as shortwave radiation in the form of ultraviolet UV rays and visible light. Once in the Earth’s atmosphere, clouds and the surface absorb solar energy. The ground heats up and re-emits the energy as longwave radiation in the form of infrared rays. 

Further Reading:

• Heating And Cooling Of The Atmosphere
• Geography Notes