This chapter suggests that the United States (US) government's evolving limited acceptance of international equity as an objective of global environmental policy was in part a function of the imperatives of international cooperation in the environmental field. The nature of the environmental issues themselves was partly determining US policy. The well-being of the United States requires that it act in cooperation with other countries to protect the natural environment. National interests—environmental, economic, and security interests—require that the US find means to bring about international environmental cooperation. Environmental changes and resource scarcities can cause social conflicts that are greater threats to the security of many countries than are traditional military threats. Recent climate change reports from the Intergovernmental Panel on Climate Change (IPCC) and the World Health Organization (WHO) have added urgency to the climate change issue. The WHO report describes expected consequences to human health from climate change.