Simplify the following text for a Grade 9 native English-speaking person.
Original: The recent rapid increase in human population over the past two centuries has raised concerns that humans are beginning to overpopulate the Earth , and that the planet may not be able to sustain present or larger numbers of inhabitants .
Simplified: The recent rapid increase in human population over the past two centuries has raised concerns that humans are beginning to overpopulate the Earth . The planet may not be able to sustain larger numbers of people .