The 2009 United Nations Summit on Climate Change, which attracted more than 100 world leaders, including the heads of state of both the United States and China, is only one recent manifestation of the growing international concern over human impact on climate. The political and economic implications of the topic, of course, are vast. Here, Science Watch® confines itself to assessing the body of research.

To examine highly cited research on climate change over the last decade, Science Watch turned to a special extraction of Thomson Reuters-indexed literature, based on such keywords as "global warming," "climate change," "human impact," and other pertinent terms, in journal articles published and cited between 1999 and the spring of 2009. This search produced upwards of 28,000 papers. From this set, Science Watch identified the most-cited institutions, authors, and journals.

Table 1a and table 1b below rank institutions according to two separate measures: first, by total citations, second, by average citations per paper (among those institutions that published at least 100 papers in the climate-change database). Highly cited authors (table 2) and journals (table 3) are also listed.

The most-cited paper in the survey is a 2002 Nature report, "Ecological responses to recent climate change," (G.R. Walther, et al., 416: 389-95, 2002), now cited approximately 1,100 times. The nine co-authors include three names from the list of highly cited scientists: Annette Menzel of the Technical University of Munich, Ove Hoegh-Guldberg of the University of Queensland, and Camille Parmesan of the University of Texas, Austin. Parmesan, in fact, also contributed to another high-visibility Nature report, now approaching 1,000 citations (C. Parmesan, G. Yohe, "A globally coherent fingerprint of climate change impact across natural systems," 421: 37-42, 2003).

Nature also accounts for the survey’s #2 most-cited paper, which tops 1,050 citations: "The genetic legacy of the Quaternary ice ages" ( G. Hewitt, 405: 907-13, 2000). Science, meanwhile, chips in with the third-most-cited paper, which examines broader aspects of assessing how species and ecosystems adapt to human disruption (J.B.C. Jackson, et al., "Historical overfishing and the recent collapse of coastal ecosystems," 293: 629-38, 2001; with just over 1,000 citations). Contributors to this report include featured authors Jeremy B.C. Jackson of UC San Diego, Terry P. Hughes of James Cook University, and John M. Pandolfi of the University of Queensland.

The survey’s most-cited author (and also the contributor to the highest number of papers in this climate-change dataset, with 57) is F. Stuart (Terry) Chapin of the University of Alaska. His top paper, with more than 800 citations, is from Science: "Biodiversity: Global biodiversity scenarios for the year 2100," (O.E. Sala, et al., 287: 1770-4, 2000).

Among institutions, the National Center for Atmospheric Research, based in Boulder, Colorado, registers the highest citation total: more than 11,000 collective cites to 360-plus papers, the most cited of which is a Science paper on climate change and its impact on coral reefs. This paper, now cited more than 450 times, also includes previously mentioned authors Hughes, Jackson, Hoegh-Guldberg, and Pandolfi. (T.P. Hughes, et al., 301: 929-33, 2003).

Among the organizations whose authors contributed to the coral-reef report is the Smithsonian Institution, which emerges at #1 by the measure of impact, or cites per paper, with 136 papers and a per-paper average exceeding 40 (with the above-mentioned blockbuster on historical overfishing providing a healthy boost).

As for journals: the multidisciplinary heavyweights Nature and Science post comparable citation tallies for their climate-themed papers, while Global Change Biology earns top citation honors among specialty journals devoted to climate change and related topics.

For more information and interviews on highly cited research on this subject, ScienceWatch.com looks at the literature on Climate Change (including four Research Front Maps) over the past decade and over the past two years.

Table 1a

Climate Change Research: Institutions, Ranked by Citations

Table 1b

Climate Change Research: Institutions, Ranked by Citation Impact

Table 2

Highly Cited Authors in Climate Change Research, 1999-2009, Ranked by Total Citations

Table 3

Most-Cited Journals in Climate Change Research, 1999-2009, Ranked by citations to papers published and cited

Christopher King is the Editor of the Science Watch® Newsletter, Thomson Reuters.