Why do many people worry about the rapid rate of global population increase?

Here is an illustration of the problem of runaway growth:


A pond has a single water lily growing on it. The lily doubles in size each day. In thirty days, it covers the entire pond. On which day does it cover half the pond? Describe the implications for population increases.

Why do many people worry about the rapid rate of global population increase?
Some cultures have a habit of destroying their environment and the planet especially Americans with their urban sprawl.





The lily cover half the pond on the 29th day and on the 30th day it doubles to cover all the pond.