The question of overpopulation is a valid one. If you have studied modern biology at a post secondary level, you may be familiar with the concept of "Caring Capacity". This is a conept related to the maximum capacity of humans that our planet is capable of supporting ecologically (based on factors of: amount of finite and renewable natural resources, pollution absorbtion, human consumption rate, etc.
For example: You are grazing cattle on a field of grass. A moderate amount of cattle on this field would consume the grass at a moderate rate, excrete at a moderate rate and the ecolocgy of the field in particular would recover at a moderate rate. Thus, an equal balance between user(cattle) and provider (field).
If one increases the amount of usership, the ecological medium cannot cope with the overload.
The same thing applies to the earth as a whole, and human usership.
To give some rounded numbers, the earth's caring capacity for humans is about 3 billion people. As of now, there are roughly 5 billion and in ten years, an estimated 11 billion.
Numbers aren't the only concern, but the nature of the predominant species should be taken into account. Humans don't just eat grass and excrete, but we have created tools which pollute more than we could from a biological standpoint, and we are tampering with highly destructive substances (nuclear, fossil fuels, toxic waste, etc.) and this opens up a the possibility for more contamination of our environment.
The results of the earth's inability to cope with human demands could result in either, the destruction of our planet (it would become inhospitable), or humankind - specifically the underdeveloped countries who don't promote environmentally friendly means for functioning - would be self0irradicated, leaving only the people living in near-pristine environments to survive (this would be a rapid decline in the population of the third world.
This is the opinion of science on the topic of overpopulation.
As far as science is concerned, you can pray all you want, but unless things change soon, there may be less humans, or no earth left.
Take heed.
None.
