Land ethic

What's changed in the last 60 years?

In 1949, the American forester and writer, Aldo Leopold wrote in his Sand County Almanac and Sketches Here and There, that what we lack is a system of ethics.

There is as yet no ethic dealing with man's relation to land and to the animals and plants which grow upon it. Land, like Odysseus' slave girls, is still property. The land-relation is still strickly economic, entailing privileges but not obligations...

And, later on in the same work:

We have no land ethic yet, but we have at least drawn nearer to the point of admitting that birds should continue as a matter of biotic right, regardless of the presence or absence of economic advantage to us.

Sixty years on, have we got the ethics we needed? Or is our relationship to the land limited to economic terms?