Do you want to help the environment but you don't know how? One way to help the environment is by building a green roof. A green roof is a roof with plants on it. The plants absorb the rain water and decrease storm water runoff. Do you want to know what storm water run off is? Well, storm water runoff is the rainwater that falls into the streets, and collects all of the gas and garbage that you don't want in Rivers or Oceans. That water collects into the gutters. When the gutters overflow, what happens is that water piles up and ends up in places like the Gowanus Canal, which makes those bodies of water really dirty.