They achieved unification in the 19th century!
There are many differences and similarities between the two routes. The type of goods is just one example. The benefactors of the Silk Road, whereas the Indian Ocean route benefited the Chinese, Indian and Middle East alike.
Human activities that contribute to desertification include the expansion and intensive use of agricultural lands, poor irrigation practices, deforestation, and overgrazing. These unsustainable land uses place enormous pressure on the land by altering its soil chemistry and hydrology.