The researchers based their study on the Thomson Reuters Web of Science® database to analyze not only the number of top-cited articles published by an institution, but also to assess scientific publications resulting from collaborations and to follow the lifespan and history of a particular article, all of which are indicators of significance of a research report in the scientific community. The database contains citation data for more than 11,000 research journals, from the fields of science, social sciences as well as arts and humanities.

To obtain a measure of scientific significance and productivity in the area of environmental sciences, the authors studied the impact of published scientific papers with regard to their country of origin and institution. Specifically, they selected the articles from top environmental science journals that were cited more than 500 times in subsequent publications. The more often an article is cited by other researchers, the more important it is deemed in the scientific community.

Most of the top-cited articles were published in the U.S., with the UA ranking No. 4 in the overall ratings, behind the U.S. Geological Survey, Brunel University in the U.K., and U.S. Environmental Protection Agency, making the UA the nation’s top most-productive university in environmental sciences.

"The best article can be classified as an article that may be read by most of the people and also cited in peer-reviewed journals," the authors wrote in their report, adding that "analysis of the top-cited articles in a field provides a historical perspective in the scientific advancement of research, evolution and areas of intensive research activities."

"I'm impressed that this study placed our close federal partner, the U.S. Geological Survey, as the top-ranked environmental governmental institution in the world," said Overpeck. "This all means we are having impact in helping real people deal with environmental challenges, but also that we're giving the state, federal and other funders a high return on their investment."

Diana Liverman, Regents Professor of Geography and Development and co-director of the UA Institute of the Environment, said: "Some might say it’s a limited analysis, but it is the main environmental science citation index, and it shows how good we are especially in regard to water-related research, remote sensing, climate and research on land-use change and ecology."

"Environmental scientists at the UA are publishing many important multi-authored articles, which is characteristic of major collaborations," she added. "It's something that really makes us stand out. We’re very good at working with each other and as part of multi-disciplinary, national and international teams."

"The journals that were evaluated for this study are some of the specialist environmental publication outlets," she said. "In addition to those, it is exciting to note the frequency with which our research gets published in the top-tier science journals like Nature and Science, where I would guess a UA-affiliated environmental researcher publishes a paper every month or so."

Environmental science and policy at the UA spans a wide range of disciplines, institutes, departments and colleges, with many researchers affiliated with the Institute of the Environment.

Liverman pointed out that several publications identified as seminal papers were authored by UA longtime researchers who are reaching retirement, but UA expertise has been maintained through new hires and collaborations. More than 30 new faculty members – with about half being women and with diverse backgrounds – have joined the UA in environmental science and policy across the university over the last three years.

"We are reinvesting in our excellence in the environment," Liverman said. "As some of our leading, often still productive faculty are moving into retirement, we have brought in a new generation of rising environmental stars, and we also were able to attract high-profile, faculty at the peak of their careers. They would all tell you that a major reason they came here is the University’s interdisciplinary environment, where the barriers to collaboration are very low."

Liverman pointed to the UA Biosphere 2 as an example of such a highly collaborative endeavor in environmental science spearheaded by the UA.

"The way that our environmental scientists have turned that into a serious research facility is impressive and well recognized in the scientific community. The recently completed Landscape Evolution Observatory is the sort of facility that should produce the type of publications and articles that are seminal."

The UA’s standing in the environmental field is also reflected by a host of interdisciplinary centers of excellence, which conduct research in topics such as water resources, solar energy, mining impactsand use-inspired climate science.

Liverman, who has served on several national committees focusing on climate, said: "We have a reputation in Washington, D.C. for the science we do here and the ways we make it useful to society, and one of the reasons we continue to get those large grants is that we encourage research on highly relevant areas, particularly in areas like the security of our water supply, energy, food and environmental health."

Among the authors of the recently released draft national climate assessment, more are at the UA than from any other university.

Liverman pointed out that the advances made at the UA don’t stay in the scientific community alone. "Our environmental scientists have an strong commitment of sharing their results with stakeholders, in line with our mission as a land-grant university."