Efficient Spiritual Environmentalism

Some time ago, I asked my friend if the environment has inherent value (value independent from human good; this was a loaded question), and in response he said that he didn't think it had any inherent value, but that the environment is valuable because humans have an inherent spiritual attachment to the earth. I had not considered this before, but I have to admit it is possible that a lot of people feel this way. I doubt that spiritual attachment to the earth is inherent, but it is certainly possible that many people do have such an attachment. I have to hope that this is not the case because I can't imagine any sort of public good more difficult to measure and legislate for than a spiritual good. Coupled with the difficulties in measuring environmental effects and estimating their costs, the problem of achieving relatively efficient behavior becomes almost intractable. Think about the problems we have in measuring global warming and the costs of its effects and then imagine how impossible the problem would be if we also had to measure how much people valued the environment itself.