Two American economists, Elinor Ostrom and Oliver Williamson, who study the way decisions are made outside the markets on which many other economists focus, were awarded the Nobel Prize in economics Monday. The judges cited "her analysis of economic governance, especially the commons," the way in which natural resources are managed as shared resources. It is an area of research that she said was relevant to questions surrounding global warming, and suggests that decisions by individuals can help solve the problem even as governments work to reach an international agreement. Ms. Ostrom "challenged the conventional wisdom that common property is...