What would be the effect on global food webs if the sun's energy could no longer reach Earth?

All plant life on earth would die, a result of the sun passing energy in the form of light energy. Plants consume light energy and grow, through photosynthesis.

If the suns energy no longer reached earth, the plants would not be able to photosynthesize any longer. So they would likely die. Also, it would be really cold.

They would more than likely die out