These costs — along with an expanded bureaucracy, more social support programs, and an expanded criminal justice system to deal with the social stresses of a larger population — must be paid for through increased fees and taxes.
As more people compete for limited resources, environmental damage will increase. As resource scarcity and economic inequity increase, social, ethnic, and political tensions will increase, along with migration and immigration as responses. And as shortages of essential resources such as farmland, water, forests, and fisheries deepen, civil and trans-boundary conflict over those resources will increase.
In short, the combination of rapid population growth and wasteful, unsustainable lifestyles on the part of some industrialized countries is degrading the environment, and diminishing our own quality of life. Left unchecked, this will ultimately threaten not only the well-being, but even the lives of the majority of people on this planet.
That outcome is not inevitable, however. We possess the knowledge, the technology, and the resources to create a just, humane, and sustainable world. The challenge we confront – the greatest ever confronted by the human species - will be to make the commitment and the necessary sacrifices to achieve that outcome.

"You must be the change you want to see in the world"
Gandhi

"If you don't change course, you'll end up where you're headed."
Ancient Chinese proverb.