This woman seems to believe that she’s helping to save the planet by not having any kids. Her math is pretty simple: a few more human beings means less resources, more burden on the environment, and so on. She likes the environment the way it is it seems, and fair enough.
But I think she’s got it totally backwards. Economist Julian Simon had it right, I think: the lesson of human progress is that more people means more minds to solve problems, and we can ultimately solve problems faster than we make them. What matters is not the number of people, but whether they have the education and the political and economic liberty to act and adapt. That doesn’t mean we can’t improve and preserve the natural environment if that’s what we value. It’s just that the only plausible way we’ll be able to do so is via political and technological solutions.
Less kids doesn’t do anything to bring those solutions about, and it just as well might mean less scientists, thinkers, and workers willing to innovate those solutions and then bring them into being. Worse, if she presumably would have raised her kids to care about the environment, it will also just mean a lower percentage of people on the planet that share that value!
Less total people does not necessarily mean more resources consumed in any case. If the supply of human beings is lower, then this means the price of the world’s resources overall will be less (since the supply is the same, but demand has reduced): everyone left could and probably would just ultimately consume more. Less people just means bigger shares of the earth for everyone else, not less consumption period.
So this woman’s decision to sterilize herself is probably pointless, at least insofar as reaching her goal of a cleaner earth. Luckily, someone has already thought of a solution to such poor judgment: tubal ligations can now be surgically reversed!