The threat of global environmental change has tended to focus on the possible impacts of a changing environment on agriculture and the implications for global food security. From a policy viewpoint, however, it is also difficult to understand the level to which agriculturally related activities may contribute to global-scale environmental change and the extent to which policies to prevent, mitigate, or adapt to environmental change may affect agriculture and hunger. These issues are likely to become especially important in making decisions not only about how to reduce the magnitude of human perturbations to the environment but also about how to improve both food security and environmental quality in the more crowded world of today and the future. This paper highlights the close linkages between agriculture, environment, and hunger in the past, reviews some of the ways in which the global food system interacts with the global environment in the present, and raises some questions regarding agriculture, environment, and hunger in the future. The primary focus of the paper is on global-scale changes in the environment, including possible changes in the earth's climate to enhance environmental sustainability of agricultural products in our society.