Scientists understand how global ecological degradation is occurring but not why it seems to be so difficult to reverse. We used national-level data and a mathematical model to provide an empirical test of the hypothesis that national economies display two distinct economic regimes that are maintained by self-reinforcing feedbacks between natural resources and society. Our results not only support previous findings that two distinct groups exist, but also show that countries move toward one of these two different equilibrium points because of their different patterns of natural resource use and responses to population growth. At the less economically developed equilibrium point maintained by “green-loop” feedbacks, human populations depend more directly on ecosystems for income. At the more economically developed equilibrium point maintained by “red-loop” feedbacks, nonecosystem services (e.g., technology, manufacturing, services) generate the majority of national gross domestic product (GDP), but increasing consumption of natural resources means that environmental impacts are higher and are often exported (via cross-scale feedbacks) to other countries. Feedbacks between income and population growth are pushing countries farther from sustainability. Our analysis shows that economic growth alone cannot lead to environmental sustainability and that current trajectories of resource use cannot be sustained without breaking feedback loops in national and international economies.

科学家们了解全球生态退化是如何发生的，但不知道为什么它似乎如此难以逆转。我们使用国家级数据和数学模型对以下假设进行实证检验：国民经济表现出两种不同的经济体制，这两种经济体制是通过自然资源和社会之间的自我强化反馈来维持的。我们的结果不仅支持了先前的发现，即存在两个不同的群体，而且还表明，由于自然资源使用模式和对人口增长的反应不同，各国正在向这两个不同的平衡点之一迈进。在由“绿色环路”反馈维持的经济欠发达的平衡点，人类更直接地依赖生态系统获取收入。在由“红环”反馈维持的经济更加发达的平衡点，非生态系统服务（例如技术、制造、服务）产生了大部分国民国内生产总值（GDP），但自然资源消耗的增加意味着环境影响更高，并且经常出口（通过跨尺度反馈）到其他国家。收入和人口增长之间的反馈正在推动各国远离可持续发展。我们的分析表明，仅靠经济增长无法实现环境可持续性，如果不打破国内和国际经济的反馈循环，当前的资源利用轨迹就无法维持。