In a Nutshell
From The World We Wish to See: Revolutionary Objectives in the Twenty-First Century, by Samir Amin (translation by James Membrez):
Capitalism has reached a stage in its development where its victim (its opponent) is no longer formed exclusively by the proletariat, whose labor it exploits, but by humanity as whole, whose survival it threatens. [...] In two areas, liberal capitalism (and doubtless capitalism, period) is already an obsolete system: in its relations with the peasantry (half of humanity) and in the waste of the planet's natural resources that its continual deployment entails.
The continuing accumulation of capital henceforth requires the destruction of peasant societies, which make up half of humanity, through the spread of a policy of "enclosures" on a world scale, without the system being able to employ the peasants, who have been chased from the countryside for industrial activities and profitable services. The size of the challenge posed by the increasingly rapid construction of a planet of shantytowns should not be underestimated.
It also leads to the rapid exhaustion of nonrenewable resources, the accelerated destruction of biodiversity and the exacerbation of the threats that strongly affect the ecological balances that are essential for the reproduction of life on Earth. Incontestable quantified data exist which demonstrate that capitalist civilization cannot continue its destructive expansion for long. Preserving the way of life of the United States alone would lead to pillaging all of the resources of the planet for its sole benefit. The energy crisis has already produced military aggression in the Middle East. "The American way of life is non negotiable," the president of this country reminds us. In other words, the extermination of the "redskins," who hinder U.S. expansion, will be continued.