Khan Quest said:
The book may be convincing, but there is not enough data to conclude the Easter Islanders, Maya, orAnasazi failed for ecological reasons. The Norse Greenland colonies, Yes. And modern-day Rwanda, perhaps.
That the Easter Islanders chopped down all their trees was already mentioned.
The Maya, once their population reached a certain level, began cultivating the previously forest-covered hill sides - but only for a relatively short time, since they were less fertile, and what's worse, they now eroded and the sediments began to cover the previously fertile valleys, thus further reducing agricultural output. Archaeological evidence is pretty firm on this.
The Anasazi also chopped down the trees on their mountains, which was revealed through, I kid you not, age analysis of pack rat middens (the dried nests of pack rats that contains both rat excrements and remains of plants and animals - these middens can survive for several
tens of thousands of years in the dry air of the area). To make a long story short, middens from before human habitation have an abundance of evidence for the existence of trees and other wild plants, which decrease and eventually vanish once humans arrive. There is also some archaeological evidence in how use of logs in house construction decreases.
They also had a unstable water management system, where they were dependent on rains in remote valleys that might or might not come each year. And at some point, their population increased to a point where it could be supported through some wet decades, but during a period of droughts it collapsed, leading to starvation, civil war (further decreasing agricultural output), and even cannibalism (again, there is archaeological evidence for this).
Again, I want to stress that all this is only a very short summary of what you can read in the book...
In general, technology allows a civilization adapt to the degradation of the environment, making collapse a rare exception.
It is very hard to replace wood once you have lost it, for instance. The Easter Islanders lost the ability to build ocean-going ships and were confined to crats that were little more than rafts, and their population shrank to about 10% of their former numbers. And the Anasazi and the Maya vanished entirely.
And sure, many civilizations survive for a long time - but most of these have had the fortune of being in exceptionally stable environments. In other regions, ecological collapses have happened more often than most people think...