The activities by humans are both positive and negative.
Building dams,harvesting water,planning irrigation,supplying piped water to far off places,developing forest land for agricultural purpose,maintaing land as green lungs, and so on. The list is endless
De-forestation, making way for concrete jungles.
Spilling oil in deep waters thereby killing marine life and subjecting lives to disaster
Neglecting forest land and burning them for woods and other liveihood.
Pumping in toxic waste in sea from industries,which ruin agriculture