The American way of life is the biggest threat to the American way of life.
We act as if we believe that we own and run the world. Careless, wasteful, more than a little bit cocky and self-centered — these traits have defined Americans and our way of life for several generations. It is time for us to become more thoughtful, careful stewards of our natural resources, and more respectful of those other nations with whom we share the earth. If we fail to adjust our attitude, it will become literally impossible for future Americans to enjoy anything like the lifestyle the baby boomers, their parents, and subsequent generations have enjoyed.
if they aren't able to grow it anymore, they will lose a lot of money that they need
The Great Wall is a fortificated East-to-West line which historically has delimited the Chinese Northern border. Its primary purpouse was to defend the Chinese territory against the invasions and quick raids organized by the nomadic people from the Eurasian Steppe lands, located more to the North.
But rather than as a fixed border, it should be regarded as a transition zone which establishes a distinction between two different lifestyles, even nowadays: the farmer regions in the South with sedentary ways of life and the pasture lands in the North, where its inhabitants have nomadic lifestyles and work mainly in animal husbandry activities.