Carbon dioxide (CO2) re-emitting infrared light, animation. Sunlight comes from top left and strikes the ground, which then emits infrared light. The infrared light is absorbed by the CO2 molecule (top right) and then re-emitted in random directions. This scatters the energy that would otherwise travel out into space and adds to the heating of the atmosphere. This is the basis of the greenhouse effect. roughly half of the emitted photons will travel back towards the surface, thereby slowing the loss of energy into space.