There is no question that great destruction of parts of the earth has already taken place through excessive deforestation, uncontrolled pollution of the atmosphere, and spoiling of the waterways.
حدود ۲۵ سال پیش باربارا وارْد و رُنه دوبو در کتابشان با عنوان تنها یک زمین (‏ انگل‍ .‏ )‏