For over three decades Dunlap has studied the nature and sources of "environmental concern," trends in public opinion toward environmental issues, and the linkage between public opinion and environmental policy-making.  As a result of this work Dunlap was appointed Gallup Fellow in Environment at the George H. Gallup International Institute, where he served as Project Director for a 24-nation environmental opinion survey in 1992.  In 1999 he was appointed Gallup Scholar for Environment with the Gallup Organization, serving as advisor for the Gallup Poll’s environmental surveys.  

Dunlap's early research examined the link between traditional American beliefs and values (e.g., individualism, laissez faire, and progress) and environmental attitudes and behavior.  He was the first researcher to examine empirically the relationship between acceptance of the basic beliefs and values constituting our society's "Dominant Social Paradigm" (or “DSP”) and concern for environmental quality.  He also developed a measure of the core elements of the "environmental paradigm" or "worldview" that has begun to challenge the DSP in most industrialized nations.  The "New Environmental Paradigm Scale" (revised at the New Ecological Paradigm Scale in 2000) has become the most widely used measure of environmental concern, employed in hundreds of studies in numerous nations around the world.  

His current research focuses primarily on climate change, including analyses of public opinion toward climate change, the growing political polarization over climate science and policy, and the sources and nature of climate change denial. Dunlap serves as Chair of the American Sociological Association’s Task Force on Sociology and Global Climate Change (2010-2012), charged with developing and synthesizing sociological analyses of the social, cultural, political and economic dimensions of climate change. 

Dunlap has been very active in the development of "environmental sociology," serving as Chair of the American Sociological Association's Section on Environmental Sociology, the Rural Sociological Society's Natural Resources Research Group and the Society for the Study of Social Problems' Environmental Problems Division.   Most recently he served as President (1994-98) of the International Sociological Association's Research Committee on Environment and Society (RC 24).

With William Catton, Dunlap co-authored a series of articles that defined and codified the field of environmental sociology, and earned them a "Distinguished Contribution Award" from the ASA Section and an "Award of Merit" from the RSS Research Group.  Their contributions were acknowledged in an article, "The Emergence of Environmental Sociology:  Contributions of Riley E. Dunlap and William R. Catton, Jr.," in a special issue of Sociological Inquiry (November, 1989) devoted to profiles of "individuals whose contributions ... prompted the exploration of new frontiers of sociological study."  More recently Catton’s and Dunlap’s work was the subject of a five-article symposium for the “Citation Classics and Foundational Works” section of Organization and Environment (December, 2008), a leading environmental social science journal.

Dunlap's work has been published in sociology journals such as the Annual Review of Sociology, American Sociological Review, and Rural Sociology; in social science journals such as Public Opinion Quarterly, Social Science Quarterly, and the Policy Studies Journal; and in multidisciplinary environmental journals such as Environment and Behavior, Environment, and Environmental Politics.  He is senior editor of American Environmentalism (Taylor and Francis, 1992), Public Reactions to Nuclear Waste (Duke University Press, 1993), the Handbook of Environmental Sociology (Greenwood, 2002) and Sociological Theory and the Environment (Rowman-Littlefield, 2002) and co-author of Viewing the World Ecologically (Westview, 1992). 

In 2000 Dunlap was elected a Fellow of the American Association for the Advancement of Science, and that year he also received the Faculty Distinguished Achievement Award from WSU’s College of Liberal Arts.  In 2002 he was awarded the Excellence in Research Award from the Rural Sociological Society in recognition of his contributions to the field of environmental sociology, and in 2010 was elected a Fellow of the American Psychological Association, Division on Population and Environmental Psychology.