translation.en: Our global system is evolving from the vertically integrated empires of the 19th century, through the horizontally interdependent nations of the 20th century, into a global network civilization in the 21st century.
translation.zh: 我们的地球系统正在进化， 从19世纪垂直一体化的帝国， 变成20世纪横向相互依存的国家， 直到21世纪的国际网络化文明。