Genesis 13:6-7 And the land was not able to bear them, that they might dwell together: for their substance was great, so that they could not dwell together. And there was a strife between the herdmen of Abram's cattle and the herdmen of Lot's cattle: and the Canaanite and the Perizzite dwelled then in the land.
The Hebrew word for bear or sustain there is nasa: A primitive root; to
lift, in a great variety of applications, literally and figuratively, absolutely and relatively.
Some might take this to mean there was "unsustainable development" and that they were taking too much from the land. The context seems to imply less about ecology and more about their stuff. They had too many things, and the fact of the land is, two things cannot occupy the same space at the same time.
How often do we acquire so many things that we can no longer even live together?