“Overpopulation” is one of them. “Gay” is another. You can insist on calling yourself gay out of a stubborn refusal to let language evolve, but unless you are gay, you will be giving a lot of people the wrong impression.

The word “overpopulation” (which remains vague and poorly defined) has fallen out of favor and is rarely used in polite company. We can thank, at least in part, those who called for an increase in death rates and draconian restrictions on childbirth for that. They provided the fuel needed by hatemongers like Ann Coulter to make comments like, “We believe in populating the earth until there’s standing room only, and then colonizing Mars.”

It has also been interesting to watch, over the last 30 years, organizations like ZPG change their names (Population Connection) and evolve into, basically, women’s reproductive-rights organizations, joining ranks with NARAL, NOW, and Planned Parenthood. Having won the struggle for lower fertility rates, these organizations now fight a running battle to protect past gains. Read this article from the Associated Press to see how well that battle is going:

Abortion access in many states is being curtailed, activists are uncertain about the stance of the U.S. Supreme Court, and South Dakotans vote Nov. 7 on a measure that would ban virtually all abortions in their state, even in cases of rape and incest.

Correction: The original post said that NPG [not ZPG] had changed their name.

I just received Population Connection’s 2006 Congressional Report in the mail. What I found inside was shocking. Almost without exception, Republicans voted against reproductive-rights bills, Democrats for them. There were a few Democrats from the Bible Belt states with less than perfect records but even they put all other Republicans to shame. Now, to be honest, most politicians disgust me. They disgusted Mark Twain also. I’m no Mark Twain, but at least I share that with him. In the end, you often just have to pick the least of two evils and the least of those evils is pretty obvious to me.

You might be asking what women’s reproductive rights have to do with environmentalism. Well, the answer to that is: pretty much everything. The root causes of our environmental ills are the wants, needs, and desires of unimaginably huge numbers of people. Family planning is also one of the keys in helping to relieve poverty, which in turn helps to further reduce fertility rates as people climb the economic ladder. Poverty reduction and family planning go hand in hand, one begetting the other in a closed loop.

It isn’t just the magnitude that matters, but more importantly, the rate of growth matters. If population growth inside a given boundary is too great, technology, economic growth, and infrastructure can’t keep up with it. The result being the poverty and ecological destruction seen in many parts of the developing world today (Indonesia, India, Africa).

Now, everyone deserves to be here, so our solutions must fit within this framework of billions of people. However, reducing the rate of births by helping women dodge unplanned pregnancies is critically important. If our low fertility rates of today had been in place half a century ago, there might be only 200 million people in India today instead of 1.3 billion, their rivers might not be open sewers, and the wild Bengal tiger might not be on its last legs.

Let me put this into perspective with some more numbers. Half of all pregnancies in the richest country in the world are unplanned. There are about 40 million pregnancy-termination procedures performed annually worldwide. There were about 70 million people added to the world population last year. I made a spreadsheet to estimate what our world population would be today if all of those procedures had been eliminated over the last 30 years as the Pope and Bush would like to see. Any guesses what that number is? And there is no way we could have gotten there today at that rate of growth.

I suspect that we can save much of what remains of our biodiversity and reduce world poverty even with 9 billion people. I would feel much more confident of that if we were already at our peak population. Also, according to the world’s leading population experts, there is no guarantee that we will stop at 9 billion. Population trends are very sensitive to slight changes in fertility rates.