2 things: one, so maybe the bible and Christians are actually right about the earth not being millions of years old. Because it is clear and logical that human growth rate is exponential. If man or animals have actually been around for a million years, there would be no space left on the planet. Now don't give me nonsense about death rates being higher in the past, it is simply not true. The highest death rate ever measured was probably during the holocaust.
2ndly, what is wrong with having more people? Have you seen how much of the planet still isn't inhabited? Have you been to Texas lately? Planet earth still has a lot of space and resources to support a few more billion. All that needs to go is greed, greedy and wasteful humans. If we can get rid of them, this planet will have no issues and will actually be a peaceful place for even 15 billion people.