The simple fact that environmental resources are endowments is found to have profound effects on their patterns of allocation with changes in income, population, and income inequality. For broad classes of theoretical models, and in Pareto efficient as well as decentralized economies, environmental quality is found to follow a U-shaped pattern with rising income. We examine population changes and variations in income inequality, and also find U-shaped patterns of behavior. Importantly, the marginal rate of substitution between consumption and environmental quality can generally be expected to rise monotonically with rising income. These results are found to have important policy implications.