The raised fields of the Tiwanalcu may be a good example of a complex society already responding to the challenges of a marginal environment,and therefore vulnerable to sudden climate change.

• 提瓦那库的高地农业可以做为一个绝好的例子来说明一个复杂的社会对于边缘环境的挑战已作出反应，但也因此易于受到气候突变的伤害。