Brad DeLong's Semi-Daily Journal: Taking the Long View: "He elaborated a bit on his book's account of the Easter Island collapse, where a society that could build 80-ton statues 33 feet high and drag them 12 miles, and who could navigate the Pacific Ocean to and from the most remote islands in the world, could also cut down their rich rain forest and doom themselves utterly. With no trees left for fishing canoes, the Easter Islanders turned to devouring each other. The appropriate insult to madden a member of a rival clan was, 'The flesh of your mother sticks between my teeth!' The population fell by 90% in a few years, and neither the society nor the island ecology have recovered in the 300 years since.
"Diamond reported that his students at UCLA tried to imagine how the guy who cut down the LAST tree in 1680 justified his actions. What did he say? Their candidate quotes: 'Fear not. Our advancing technology will solve this problem.' 'This is MY tree, MY property! I can do what I want with it.' 'Your environmentalist concerns are exaggerated. We need more research.' 'Just have faith. God will provide.'
"The question everyone asks, Diamond said, is, How can people be so dumb? It's a crucial question, with a complex answer. He said that sometimes it's a failure to perceive a problem, especially if it comes on very slowly, like climate change. Often it's a matter of conflicting interests with no resolution at a higher level than the interests-- warring clans, greedy industries. Or there may be a failure to examine and understand the past.
Overall, it's a failure to think long term. That itself has many causes. One common one is that elites become insulated from the consequences of their actions. "