The ailing planet the green movements' role- the required question is How are earths' principal biological systems being depleted?

ACCORDIND TO NAVNEET'S VIEW POINT IT SHOULD BE !

the four biological systems are fisheries,forests, grasslands, cropland. It is depleted because of over fishing, forest disappear for firewood, grassland and converted into barren wasteland and cropland deteriorate. Their productivity is badly affected as they are reaching now an unsustainable level. so the life support in earth os being depleted fast.