biggest threats to the environment

From the 15 topic, i personally think that man made environment is the biggest treat to the earth, example such as burning of forest, it both create land and air pollution, at the same time , it also destroy natural habitat and our health will be affect by the air pollution.next will be industries pollution, the waste are commonly discharge into the sea, i think this will greatly affect the living creature in the sea, at the same time, people eating the food will be affected too.next will be the spraying of pesticide, i believe that the pesticide will affect our health.