If you check the numbers USA Website (I just did), it addresses only illegal immigration (not birth control, not abortion).
There are some truths in what he says but he ignores other truths. The streams and lakes of the USA have gotten cleaner since the early 1900's despite the population growth. It's not a trade off scenario though that's how he presents it.
Also ignored are the huge advances in economic prosperity for the desperately poor around the world; particularly in Asia where communism is fading into captalism and the rule of law is at least making some progress.
Here's an earlier thread on the creepy John Tanton:
Father of Anti-Immigration Movement Awaits History's Judgment [Dr. John Tanton]