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2008 Bibliometric Analysis for Papers on Topics Related to Global Change (GC) (papers published 1998 to 2007)
January 8, 2008

This is a bibliometric analysis of the papers prepared by intramural and extramural researchers of the U.S. Environmental Protection Agencys (EPA) Global Change Research Program. For this analysis, 432 journal publications and 12 non-journal publications were reviewed, and they were published from 1998 to 2007 (the programs first papers were published in 1998). The journal publications were cited 5,925 times in the journals covered by Thomson Scientifics Web of Science1 and Elseviers Scopus2 . The non-journal publications were cited 720 times in journals and books. Of the 444 publications global change publications, 397 (89.4%) have been cited at least once in a journal or book.

Searches of Web of Science and Scopus were conducted to obtain times cited data for the Global Change Research Program journal publications and searches of Web of Science and Google Scholar were conducted to obtain times cited data for the non-journal publications. The analysis was completed using Thomsons Essential Science Indicators (ESI) and Journal Citation Reports (JCR) as benchmarks. ESI provides access to a unique and comprehensive compilation of essential science performance statistics and science trends data derived from Thomsons databases. For this analysis, the ESI highly cited papers thresholds as well as the hot papers thresholds were used to assess the influence and impact of the global change papers. JCR is a recognized authority for evaluating journals. It presents quantifiable statistical data that provide a systematic, objective way to evaluate the worlds leading journals and their impact and influence in the global research community. The two key measures used in this analysis to assess the journals in which the EPA global change papers are published are the Impact Factor and Immediacy Index. The Impact Factor is a measure of the frequency with which the average article in a journal has been cited in a particular year. The Impact Factor helps evaluate a journals relative importance, especially when compared to other journals in the same field. The Immediacy Index is a measure of how quickly the average article in a journal is cited. This index indicates how often articles published in a journal are cited within the same year and it is useful in comparing how quickly journals are cited.

This report is divided into four sections. The first section presents an analysis of the 432 global change journal publications analyzed by ESI field (e.g., Geosciences, Environment/Ecology, and Engineering). The second section presents an analysis of the 12 non-journal publications analyzed by ESI field. The third section provides an analysis of the 432 global change journal publications by focus area (e.g., Air Quality, Water Quality/Aquatic Ecosystem). The fourth section of this report includes some additional parameters on global warming publications that are reported by ESI.A summary of the results of the entire bibliometric analysis precedes the four sections.

Summary of Results
  1. Analysis of Global Change Journal Publications
    1. One-fourth of the global change publications are highly cited papers. 108 (25.0%) of the global change papers qualify as highly cited when using the ESI criteria for the top 10% of highly cited publications. This is 2.5 times higher than the 10% of papers expected to be highly cited. 12 (2.8%) of the global change papers qualify as highly cited when using the ESI criteria for the top 1%, which is 2.8 times higher than the number expected. 2 (0.5%) of these papers qualify as very highly cited when using the criteria for the top 0.1%, which is 5 times higher than the number anticipated. 1 (0.2%) of the papers actually meets the 0.01% threshold for the most highly cited papers, which is surprising given that the expected number for this program is 0.04 papers.
    2. The global change papers are more highly cited than the average paper. Using the ESI average citation rates for papers published by field as the benchmark, in 10 of the 14 fields in which the 432 EPA global change papers were published, the ratio of actual to expected cites is greater than 1, indicating that the global change papers are more highly cited than the average papers in those fields. For all 14 fields combined, the ratio of total number of cites to the total number of expected cites (5,925 to 3,332.72) is 1.8, indicating that the global change papers are more highly cited than the average paper.
    3. One-fourth of the global change papers are published in high impact journals. 104 of the 432 papers were published in the top 10% of journals ranked by JCR Impact Factor, representing 24.1% of EPAs global change papers. This number is 2.4 times higher than the expected 43 papers. 123 of the 432 papers appear in the top 10% of journals ranked by JCR Immediacy Index, representing 28.5% of EPAs global change papers. This number is 2.8 times higher than the expected 43 papers.
    4. Eleven of the global change papers qualify as hot papers. Using the hot paper thresholds established by ESI as a benchmark, 11 hot papers, representing 2.6% of the global change papers, were identified in the analysis. Hot papers are papers that were highly cited shortly after they were published. The number of global change hot papers identified is 26 times higher than the expected 0.4 hot papers.
    5. The authors of the global change papers cite themselves less than the average author. 424 of the 5,925 cites are author self-cites. This 7.2% author self-citation rate is below the accepted range of 10-30% author self-citation rate.
    6. Thirty-four of the 1,006 authors of the global change papers are included in ISIHighlyCited.com,which is a database of the worlds most influential researchers who have made key contributions to science and technology during the period from 1981 to 1999.
    7. There were no patents issued to investigators from 1998 to 2007 for research that was conducted under EPAs Global Change Research Program.
  2. Analysis of the Non-Journal Global Change Publications
    1. Nearly one-half of the non-journal publications were cited at least once in a journal or book. 5 (41.7%) of the 12 publications were cited at least once in a journal or book covered by Thomsons Web of Science and Google Scholar.
    2. The 12 non-journal publications were cited 720 times. The 5 books were cited 497 times, the 2 book chapters were cited 172 times, the 4 reports were cited 31 times, and the technical paper was cited 20 times.
    3. Nearly one-half of the non-journal global change publications are highly cited using the top 10% threshold in ESI. 5 (41.7%) of the global change non-journal publications qualify as highly cited when using the ESI criteria for the top 10% of highly cited papers. This is 4.2 times the number of publications expected to be highly cited.
    4. One-fourth of the non-journal publications are highly cited using the top 1% threshold in ESI. 3 (25.0%) of the global change publications qualify as highly cited when using the ESI criteria for the top 1%, which is 25 times the number expected. 2 (16.7%) of these publications qualify as very highly cited when using the criteria for the top 0.1% and 1 (8.3%) of the papers qualify as extremely highly cited when using the criteria for the top 0.01%. These results are extraordinary given that the expected numbers are 0.012 publications and 0.0012 publications, respectively, for these two highest thresholds.
    5. The non-journal global change publications are cited more than the average paper. Using the ESI average citation rates for papers published by field as the benchmark, the ratio of actual to expected cites for every field to which the publications were assigned was greater than 1, indicating that the global change publications are cited more than the average papers in those fields. For all 4 fields combined, the ratio of total number of cites to the total number of expected cites (720 to 90.09) is 8.0, indicating that the global change publications are cited more than the average paper.
  3. Analysis of Global Change Journal Publications by Focus Area
    1. More than one-third of the Human Health and one-fourth of the Air Quality and Water Quality/Aquatic Ecosystem focus area publications are highly cited papers (this is 2.4 to 3.8 times the number expected). The percentage of global change papers that qualify as highly cited when using the ESI criteria for the top 10% of highly cited publications ranges from 4.8% for the Regional- and Place-Based Assessment papers to 38.1% for the Human Health papers. The Human Health and Water Quality/Aquatic Ecosystem focus areas have the highest percentages of highly cited publications when using the ESI criteria for the top 10%, and the number of highly cited papers in these areas is 3.8 to 2.6 times higher than expected. These two focus areas also hold the lead positions when using the ESI criteria for the top 1% of papers, and the number of very highly cited papers in these areas is 4.8 to 3.2 times higher than expected. Two (0.7%) papers in the Water Quality/Aquatic Ecosystem focus area meet the ESI criteria for the top 0.1% of papers, which is 7 times higher than the expected number for this focus area. One (0.4%) of the Water Quality/Aquatic Ecosystem papers meets the ESI criteria for the most highly cited papers (top 0.01%), which is 40 times the number expected for this focus area.
    2. The global papers are more highly cited than the average paper in three of the four focus areas. Using the ESI average citation rates for papers published by field as the benchmark, the ratio of actual to expected cites is greater than 1 for all but the Regional- and Place-Based Assessment focus area. This indicates that for three of the four focus areas, the global change papers are more highly cited than the average paper.
    3. Nearly three-fourths of the Human Health papers, one-fourth of the Water Quality/Aquatic Ecosystem papers, and one-sixth of the Air Quality papers are published in high impact journals as determined by the JCR Impact Factor and Immediacy Index of the journals in which the papers are published. The number of global change papers published in high impact journals (the top 10% of journals) exceeds the expected 10% as determined by the JCR Impact Factor and Immediacy Index of the journals. The percentage of papers in high impact journals (by Impact Factor) for Human Health, Water Quality/Aquatic Ecosystem, and Air Quality ranges from 73.8% to 22.3% to 15.2%, which is 7.4, 2.2, and 1.5 times higher than expected, respectively. None of the Regional- and Place-Based Assessment papers are published in high impact journals determined by Impact Factor. The percentage of papers in high impact journals (by Immediacy Index) for three of the four focus areas is higher than expected, ranging from 73.8% for the Human Health papers to 30.3% for the Air Quality papers to 25.2% for the Water Quality/Aquatic Ecosystem papers. These percentages are 7.4, 3.0, and 2.5 times higher than expected, respectively. Only 1 (2.4%) of the Regional- and Place-Based Assessment papers was published in a high impact journal determined by Immediacy Index.
    4. In all four of the focus areas, the percentage of publications cited one or more times is very high (i.e., 84.8% to 95.2%).
    5. The authors of the global change papers cite themselves less than the average self-citation rate. The author self-citation rates range from 4.0% to 14.3%. The rates for the Human Health, Regional- and Place-Based Assessment, and Water Quality/Aquatic Ecosystem focus areas are well below the accepted range of 10-30% author self-citation rate, and the rate for the Air Quality papers is 14.3%, which is within the accepted range.
    6. There were hot papers published in three of the four focus areas. The highest percentage of hot papers (i.e., 9.5%) is in the Regional- and Place-Based Assessment focus area, followed by the Air Quality focus area at 3.0% and the Water Quality/Aquatic Ecosystem focus area at 1.8%. These percentages are 95, 30, and 18 times higher than expected for these focus areas, respectively. There were no hot papers in the Human Health focus area.
  4. Comparison of EPAs Global Change Publications to ESIs Top Global Warming Publication Parameters
    1. EPAs Global Change Research Program includes 1 (5.0%) of ESIs top 20 global warming papers (published from January 1996 to April 2006).
    2. The United States ranks first among the top 20 countries publishing on global warming.
    3. Nearly one-fourth of the EPA global change papers were published in ESIs top 20 journals in global warming.
    4. Thirteen (65%) of the top 20 institutions publishing on global warming participate in EPAs Global Change Research Program.
    5. The number of cites and cites per paper for global warming papers have begun to decline in recent years and this trend holds true for the EPA global change papers.

I. Analysis of Global Change Journal Publications by ESI Field

Highly Cited Global Change Journal Publications

All of the journals covered by ESI are assigned a field, and to compensate for varying citation rates across scientific fields, different thresholds are applied to each field. Thresholds are set to select highly cited papers to be listed in ESI. Different thresholds are set for both field and year of publication. Setting different thresholds for each year allows comparable representation for older and more recent papers for each field.

The 432 global change research papers reviewed for this analysis were published in journals that were assigned to 14 of the 22 ESI fields. The distribution of the papers among these 14 fields and the number of citations by field are presented in Table 1.

Table 1. Global Change Papers by ESI Fields


ESI Field

No. of Citations

No. of Global Change Papers

Average Cites/Paper

Agricultural Sciences

8

1

8.0

Biology & Biochemistry

108

10

10.8

Clinical Medicine

352

16

22.0

Computer Science

7

1

7.0

Economics & Business

25

2

12.5

Engineering

374

47

8.0

Environment/Ecology

2,103

175

12.0

Geosciences

1,372

87

15.8

Immunology

30

2

15.0

Microbiology

113

6

18.8

Multidisciplinary

820

12

68.3

Physics

4

1

4.0

Plant & Animal Science

568

65

8.7

Social Sciences, general

41

7

5.8

Total = 5,925

Total = 432

13.7

There are 108 (25.0% of the papers analyzed) highly cited EPA global change papers in 10 of the 14 fieldsClinical Medicine, Computer Science, Economics & Business, Engineering, Environment/ Ecology, Geosciences, Microbiology, Multidisciplinary, Plant & Animal Science, and Social Scienceswhen using the ESI criteria for the top 10% of papers. Table 2 shows the number of global change papers in those 10 fields that meet the top 10% threshold in ESI. These publications are listed in the Appendix.

Twelve (2.8%) of the papers analyzed qualify as highly cited when using the ESI criteria for the top 1% of papers. These papers cover six fieldsEngineering, Environment/ Ecology, Geosciences, Microbiology, Multidisciplinary, and Plant & Animal Science. Table 3 shows the 12 (2.8% of the papers analyzed) papers by field that meet the top 1% threshold in ESI. The citations for these 12 papers are provided in Tables 4 through 9. The highly cited papers in Tables 4 through 9 are presented in order of year of publication with the oldest papers appearing first. Within the year of publication, the papers are ordered by increasing number of times cited.
Table 10 shows the number of papers by field that meet the top 0.1% threshold in ESI. These 2 (0.5%) very highly cited global change papers in the fields of Multidisciplinary and Plant & Animal Science are listed in Table 11. One (0.2%) of the global change papers meets the top 0.01% threshold in ESI, which is 20 times higher than expected. This is extraordinary because the expected number of papers that should meet this threshold for this analysis is 0.04. The paper that meets the top 0.01% threshold in ESI is presented in Table 12.

Table 2. Number of Highly Cited Global Change Papers by Field (top 10%)


ESI Field

No. of Citations

No. of Papers

Average Cites/Paper

% of Papers in Field

Clinical Medicine

213

3

71.0

18.8%

Computer Science

7

1

7.0

100.0%

Economics & Business

23

1

23.0

50.0%

Engineering

235

9

26.1

19.1%

Environment/Ecology

955

32

29.8

18.3%

Geosciences

1,047

34

30.8

39.1%

Microbiology

113

4

28.2

66.7%

Multidisciplinary

820

9

91.1

75.0%

Plant & Animal Science

258

14

18.4

21.5%

Social Sciences, general

11

1

11.0

14.3%

Total = 3,682

Total = 108

34.1

25.0%

Table 3. Number of Highly Cited Global Change Papers by Field (top 1%)


ESI Field

No. of Citations

No. of Papers

Average Cites/Paper

% of Global Change Papers in Field

Engineering

75

1

75.0

2.1%

Environment/Ecology

125

1

125.0

0.6%

Geosciences

227

4

56.8

4.6%

Microbiology

41

1

41.0

16.7%

Multidisciplinary

640

4

160.0

33.3%

Plant & Animal Science

6

1

6.0

1.5%

Total = 1,114

Total = 12

92.8

2.8%

Table 4. Highly Cited Global Change Papers in the Field of Engineering (top 1%)


No. of Cites

ESI Threshold

First Author

Paper

75

46

Douglas EM

Trends in floods and low flows in the United States: impact of spatial correlation. Journal of Hydrology 2000;240(1-2):90-105.

Table 5. Highly Cited Global Change Papers in the Field of
Environment/Ecology (top 1%)


No. of Cites

ESI Threshold

First Author

Paper

125

82

Marsh DM

Metapopulation dynamics and amphibian conservation. Conservation Biology 2001;15(1):40-49.

Table 6. Highly Cited Global Change Papers in the Field of Geosciences (top 1%)


No. of Cites

ESI Threshold

First Author

Paper

96

89

Chase TN

Simulated impacts of historical land cover changes on global climate in northern winter. Climate Dynamics 2000;16(2-3):93-105.

113

89

Moran MA

Carbon loss and optical property changes during long-term photochemical and biological degradation of estuarine dissolved organic matter. Limnology and Oceanography 2000;45(6):1254-1264.

12

10

Howarth RW

Nitrogen as the limiting nutrient for eutrophication in coastal marine ecosystems: evolving views over three decades. Limnology and Oceanography 2006;51(1):364-376.

6

4

Wu SL

Why are there large differences between models in global budgets of tropospheric ozone? Journal of Geophysical Research-Atmospheres 2007;112(D5):Art. No. D05302.

Table 7. Highly Cited Global Change Papers in the Field of Microbiology (top 1%)


No. of Cites

ESI Threshold

First Author

Paper

41

34

Jiang SC

Genetic diversity of clinical and environmental isolates of Vibrio cholerae determined by amplified fragment length polymorphism fingerprinting. Applied and Environmental Microbiology 2000;66(1):148-153.

 

Table 8. Highly Cited Global Change Papers in the Field of Multidisciplinary (top 1%)


No. of Cites

ESI Threshold

First Author

Paper

57

51

Brutsaert W

Hydrologic cycle explains the evaporation paradox. Nature 1998;396(6706):30-30.

94

57

Pascual M

Cholera dynamics and El Nino-Southern Oscillation. Science 2000;289(5485):1766-1769.

448

82

Root TL

Fingerprints of global warming on wild animals and plants. Nature 2003;421(6918):57-60.

41

27

Worm B

Impacts of biodiversity loss on ocean ecosystem services. Science 2006;314(5800):787-790.

Table 9. Highly Cited Global Change Papers in the Field of
Plant & Animal Science (top 1%)


No. of Cites

ESI Threshold

First Author

Paper

6

3

Bullard SG

The colonial ascidian Didemnum sp A: current distribution, basic biology and potential threat to marine communities of the northeast and west coasts of North America. Journal of Experimental Marine Biology and Ecology 2007;342(1):99-108.

Table 10. Number of Very Highly Cited Papers by Field (top 0.1%)


ESI Field

No. of Citations

No. of Papers

Average Cites/Paper

% of Global Change Papers in Field

Multidisciplinary

448

1

448.0

8.3%

Plant & Animal Science

6

1

6.0

1.5%

Total = 454

Total = 2

227.0

0.5%

Table 11. Very Highly Cited Global Change Papers (top 0.1%)


ESI Field

ESI Threshold

No. of Cites

First Author

Paper

Multidisciplinary

339

448

Root TL

Fingerprints of global warming on wild animals and plants. Nature 2003;421(6918):57-60.

Plant & Animal Science

3

6

Bullard SG

The colonial ascidian Didemnum sp A: current distribution, basic biology and potential threat to marine communities of the northeast and west coasts of North America. Journal of Experimental Marine Biology and Ecology 2007;342(1):99-108.

Table 12. Extremely Highly Cited Global Change Papers (top 0.01%)


ESI Field

ESI Threshold

No. of Cites

First Author

Paper

Multidisciplinary

339

448

Root TL

Fingerprints of global warming on wild animals and plants. Nature 2003;421(6918):57-60.

Ratio of Actual Cites to Expected Citation Rates

The expected citation rate is the average number of cites that a paper published in the same journal in the same year and of the same document type (article, review, editorial, etc.) has received from the year of publication to the present. Using the ESI average citation rates for papers published by field as the benchmark, in 10 of the 14 fields in which the global change papers were published, the ratio of actual to expected cites is greater than 1, indicating that the global change papers are more highly cited than the average papers in those fields (see Table 13). For all 14 fields combined, the ratio of total number of cites to the total number of expected cites (5,925 to 3,332.72) is 1.8, indicating that the global change papers are more highly cited than the average paper.

Table 13. Ratio of Actual Cites to Expected Cites for Global Change Papers by Field


ESI Field

Total Cites

Expected Cite Rate

Ratio

Agricultural Sciences

8

9.13

0.9

Biology & Biochemistry

108

114.85

0.9

Clinical Medicine

352

207.45

1.7

Computer Science

7

1.65

4.2

Economics & Business

25

6.01

4.2

Engineering

374

197.85

1.9

Environment/Ecology

2,103

1,616.28

1.3

Geosciences

1,372

598.58

2.3

Immunology

30

42.60

0.7

Microbiology

113

103.22

1.1

Multidisciplinary

820

41.87

19.6

Physics

4

6.83

0.6

Plant & Animal Science

568

362.94

1.6

Social Sciences, general

41

23.46

1.7

TOTAL

5,925

3,332.72

1.8

JCR Benchmarks

Impact Factor. The JCR Impact Factor is a well known metric in citation analysis. It is a measure of the frequency with which the average article in a journal has been cited in a particular year. The Impact Factor helps evaluate a journals relative importance, especially when compared to others in the same field. The Impact Factor is calculated by dividing the number of citations in the current year to articles published in the 2 previous years by the total number of articles published in the 2 previous years.

Table 14 indicates the number of global change papers published in the top 10% of journals, based on the JCR Impact Factor. One hundred four (104) of 432 papers were published in the top 10% of journals, representing 24.1% of the global change journal publications. This indicates that nearly one-quarter of the global change papers are published in the highest quality journals as determined by the JCR Impact Factor, which is 2.4 times higher than the expected percentage.

Table 14. Global Change Papers in Top 10% of Journals by JCR Impact Factor


Global Change Papers in that Journal

Journal

Impact Factor
(IF)

JCR IF Rank

4

Science

30.028

9

3

Nature

26.681

15

4

Lancet

25.800

18

1

JAMA-Journal of the American Medical Association

23.175

23

4

Proceedings of the National Academy of Sciences of the United States of America

9.643

116

1

British Medical Journal

9.245

128

1

Reviews of Geophysics

8.375

144

10

Environmental Health Perspectives

5.861

255

2

Bioscience

5.424

291

1

Journal of Infectious Diseases

5.363

298

1

American Journal of Epidemiology

5.241

308

1

Emerging Infectious Diseases

5.094

332

1

Trends in Parasitology

4.907

356

1

Frontiers in Ecology and the Environment

4.842

371

2

Ecology

4.782

381

1

Atmospheric Chemistry and Physics

4.362

449

2

Epidemiology

4.339

452

6

Global Change Biology

4.339

452

2

New Phytologist

4.245

474

2

Plant Cell and Environment

4.135

495

6

Environmental Science & Technology

4.040

518

2

Global Biogeochemical Cycles

3.796

587

8

Conservation Biology

3.762

601

1

Bulletin of the American Meteorological Society

3.728

614

2

American Journal of Public Health

3.698

626

3

Applied and Environmental Microbiology

3.532

682

1

Journal of Power Sources

3.521

686

9

Ecological Applications

3.470

708

9

Journal of Climate

3.419

728

1

Climate Dynamics

3.344

747

1

Oecologia

3.333

753

1

Global Ecology and Biogeography

3.314

764

8

Limnology and Oceanography

3.287

774

1

Microbes and Infection

3.127

833

1

Remote Sensing of Environment

3.064

855

Total = 104

 

 

Immediacy Index. The JCR Immediacy Index is a measure of how quickly the average article in a journal is cited. It indicates how often articles published in a journal are cited within the year they are published. The Immediacy Index is calculated by dividing the number of citations to articles published in a given year by the number of articles published in that year.

Table 15 indicates the number of global change papers published in the top 10% of journals, based on the JCR Immediacy Index. One hundred twenty-three (123) of the 432 papers appear in the top 10% of journals, representing 28.5% of the global change papers. This indicates that more than one-quarter of the global change papers are published in the highest quality journals as determined by the JCR Immediacy Index, which is 2.8 times higher than the expected percentage.

Table 15. Global Change Papers in Top 10% of Journals by JCR Immediacy Index


Global Change Papers in that Journal

Journal

Immediacy Index
(II)

JCR II Rank

1

JAMA-Journal of the American Medical Association

7.781

4

4

Lancet

7.419

6

3

Nature

6.789

9

4

Science

5.555

16

1

British Medical Journal

4.412

25

4

Proceedings of the National Academy of Sciences of the United States of America

1.758

126

2

Ambio

1.695

136

2

Journal of the North American Benthological Society

1.568

158

2

Epidemiology

1.437

187

9

Journal of Climate

1.343

206

1

Journal of Infectious Diseases

1.300

221

1

Emerging Infectious Diseases

1.222

243

1

Reviews of Geophysics

1.100

300

1

American Journal of Epidemiology

1.091

306

1

Atmospheric Chemistry and Physics

1.015

350

10

Environmental Health Perspectives

0.994

373

2

New Phytologist

0.970

381

3

Journal of Biogeography

0.958

391

2

Marine Chemistry

0.958

391

1

Trends in Parasitology

0.906

417

1

Global Ecology and Biogeography

0.793

529

8

Limnology and Oceanography

0.784

537

8

Conservation Biology

0.778

543

2

Plant Cell and Environment

0.777

547

1

Climate Dynamics

0.760

569

2

American Journal of Public Health

0.740

588

2

Ecology

0.724

610

2

Global and Planetary Change

0.709

635

18

Journal of Geophysical Research-Atmospheres

0.684

673

1

Agricultural and Forest Meteorology

0.669

690

6

Global Change Biology

0.660

705

2

Monthly Weather Review

0.654

716

2

Global Biogeochemical Cycles

0.652

720

6

Environmental Science & Technology

0.646

729

1

Bulletin of the American Meteorological Society

0.646

729

3

Applied and Environmental Microbiology

0.634

751

1

Environmental Research

0.583

844

2

Bioscience

0.582

848

Total = 123

 

 

Hot Papers

ESI establishes citation thresholds for hot papers, which are selected from the highly cited papers in different fields, but the time frame for citing and cited papers is much shorterpapers must be cited within 2 years of publication and the citations must occur in a 2-month time period. Papers are assigned to 2-month periods and thresholds are set for each period and field to select 0.1% of papers.

Using the hot paper thresholds established by ESI as a benchmark, 11 hot papers, representing 2.6% of the global change papers, were identified in five fieldsEngineering, Environment/ Ecology, Geosciences, Multidisciplinary, and Plant & Animal Science. The number of global change hot papers is 26 times higher than expected. The hot papers are listed in Table 16.

Table 16. Hot Papers Identified Using ESI Thresholds


Field

ESI Hot Papers Threshold

No. of Cites in 2-Month Period

Paper

Engineering

4

6 cites in July-August 2002

Douglas EM, et al. Trends in flood and low flows in the United States: impact of spatial correlation. Journal of Hydrology 2000;240(1-2):90-105.

Environment/ Ecology

5

5 cites in May 2000

Rose A, et al. Simulating the economic impacts of climate change in the Mid-Atlantic Region. Climate Research 2000;14(3):175-183.

5

5 cites in May 2000

Fisher A, et al. The Mid-Atlantic Regional Assessment: motivation and approach. Climate Research 2000;14(3):153-159.

5

8 cites in May 2000

Polsky C, et al. The Mid-Atlantic Region and its climate: past, present, and future. Climate Research 2000;14(3):161-173.

Environment/ Ecology

3

3 cites in January-February 2003

Ankley GT, et al. Assessment of the risk of solar ultraviolet radiation to amphibians. I. Dose-dependent induction of hindlimb malformations in the Northern leopard frog (Rana pipiens). Environmental Science & Technology 2002;36(13):2853-2858.

Geosciences

3

4 cites in November-December 2004

Hogrefe C, et al. Simulating regional-scale ozone climatology over the eastern United States: model evaluation results. Atmospheric Environment 2004;38(17):2627-2638.

3

3 cites in May 2007

Wu SL, et al. Why are there large differences between models in global budgets of tropospheric ozone? Journal of Geophysical Research-Atmospheres 2007;112(D5):Art No. D05302.

Multidisciplinary

10

19 cites in September-October 2004

Root TL, et al. Fingerprints of global warming on wild animals and plants. Nature 2003;421(6918):57-60.

Multidisciplinary

6

15 cites in June-July 2007

Worm B, et al. Impacts of biodiversity loss on ocean ecosystem services. Science 2006;314(5800):787-790.

Plant & Animal Science

4

5 cites in December 2002

Sousounis PJ, Grover EK. Potential future weather patterns over the Great Lakes region. Journal of Great Lakes Research 2002;28(4):496-520.

4

6 cites in March 2007

Bullard SG, et al. The colonial ascidian Didemnum sp A: Current distribution, basic biology and potential threat to marine communities of the northeast and west coasts of North America. Journal of Experimental Marine Biology and Ecology 2007;342(1):99-108.

Author Self-Citation

Self-citations are journal article references to articles from that same author (i.e., the first author). Because higher author self-citation rates can inflate the number of citations, the author self-citation rate was calculated for the global change papers. Of the 5,925 total cites, 424 are author self-citesa 7.2% author self-citation rate. Garfield and Sher3 found that authors working in research-based disciplines tend to cite themselves on the average of 20% of the time. MacRoberts and MacRoberts4 claim that approximately 10% to 30% of all the citations listed fall into the category of author self-citation. Kovacic and Misak5 recently reported a 20% author self-citation rate for medical literature. Therefore, the 7.2% self-cite rate for the global change papers is below the range for author self-citation.

Highly Cited Researchers

A search of Thomsons ISIHighlyCited.com revealed that 34 (3.4%) of the 1,006 authors of the global change papers are highly cited researchers. ISIHighlyCited.com is a database of the worlds most influential researchers who have made key contributions to science and technology during the period from 1981 to 1999. The highly cited researchers identified during this analysis of the global change publications are presented in Table 17.

Table 17. Highly Cited Researchers Authoring Global Change Publications


Highly Cited Researcher

Affiliation

ESI Field

Ankley, Gerald T

U.S. EPA

Environment/Ecology

Brown, Sandra L

Winrock International

Environment/Ecology

Caldwell, Martyn M

Utah State University

Environment/Ecology

Callaghan, Terry V

University of Sheffield

Environment/Ecology

Chase, Thomas N

NINDS

Neuroscience

Colwell, Rita R

Canon U.S. Life Sciences

Microbiology

Ehleringer, James

University of Utah

Environment/Ecology

Elliott, Edward T

University of Nebraska

Environment/Ecology

Galloway, James Neville

University of Virginia

Environment/Ecology
Geosciences
Engineering

Giorgi, Filippo

Abdus Salam International Centre for Theoretical Physics

Geosciences

Goldberg, Richard

Columbia University

Plant & Animal Science

Howarth, Robert W

Cornell University

Environment/Ecology

Jacob, Daniel J

Harvard University

Geosciences

Lauenroth, William K

Colorado State University

Environment/Ecology

Levin Simon A

Princeton University

Environment/Ecology

Logan Jennifer A

Harvard University

Geosciences

Lugo, Ariel E

USDA

Environment/Ecology

McKenzie Dan

University of Cambridge

Geosciences

Ojima, Dennis S

Colorado State University

Environment/Ecology

Palmer, T.N.

European Center for Medium Range Weather Forecasts

Geosciences

Parton, William J

Colorado State University

Environment/Ecology

Pielke, Roger A

Colorado State University

Geosciences

Rind, David H

NASA Goddard

Geosciences

Running, Steven W

University of Montana

Environment/Ecology

Sala, Osvaldo E

Brown University

Environment/Ecology

Schimel, David S

National Center for Atmospheric Research

Environment/Ecology

Schindler David W

University of Alberta

Environment/Ecology

Schwartz, Joel D

Harvard University

Environment/Ecology

Seinfeld John H

California Institute of Technology

Engineering
Geosciences

Shugart, Herman H

University of Virginia

Environment/Ecology

Teramura, Alan H

University of Hawaii

Plant & Animal Science

Wang J

U.S. National Weather Service, National Centers for Environmental Prediction

Geosciences

Zeger, Scott L

Johns Hopkins University

Mathematics

Zepp, Richard G

U.S. EPA

Environment/Ecology

Total = 34

Patents

There were no patents issued to investigators from 1998 to 2007 for research that was conducted under EPAs Global Change Research Program.

II. Analysis of Global Change Non-Journal Publications by ESI Field

This section contains a bibliometric analysis of the non-journal publications prepared by intramural and extramural researchers of EPAs Global Change Research Program. For this analysis, 12 non-journal publications4 reports, 5 books, 2 book chapters, and 1 technical paperwere reviewed. These publications were published from 2000 to 2007, and they were cited 720 times in the journals and books covered by Thomson Scientifics Web of Science and Google Scholar. All 12 (100%) of these publications have been cited at least once in a journal or book. The 4 reports were cited 31 times, the 5 books were cited 497 times, the 2 book chapters were cited 172 times, and the technical paper was cited 20 times.

Searches of Web of Science and Google Scholar were conducted to obtain times cited data for the Global Change Research Program non-journal publications. The analysis was completed using Thomsons Essential Science Indicators (ESI) as benchmarks. ESI provides access to a unique and comprehensive compilation of essential science performance statistics and science trends data derived from Thomsons databases. For this analysis, the ESI highly cited papers thresholds were used to assess the influence and impact of the global change non-journal publications.

Distribution of Non-Journal Publications Among ESI Fields

For this analysis, each publication was assigned to one of the 22 ESI fields so that the ESI thresholds for highly cited journal papers could be used to determine how many of the non-journal publications were highly cited. The 12 non-journal publications reviewed for this analysis were assigned to 4 of the 22 ESI fields. The distribution of the publications among these four fields and the number of citations by field are provided in Table 18.

Table 18. Non-Journal Global Change Publications by ESI Fields


ESI Field

No. of Citations

No. of EPA Publications

Average Cites/ Publication

Clinical Medicine

36

2

18.0

Environment/Ecology

523

7

74.7

Geosciences

151

2

75.5

Plant & Animal Science

10

1

10.0

Total = 720

Total = 12

60.0

Highly Cited Non-Journal Publications

There are 5 (41.7% of the publications analyzed) highly cited non-journal global change publications in three of the four ESI fieldsClinical Medicine, Environment/Ecology, and Geoscienceswhen using the ESI criteria for the top 10% of papers. Table 19 shows the number of global change publications in those three fields that meet the top 10% threshold in ESI. The citations of the publications that met the criteria for the top 10% of papers are presented in Table 20.

Three (25.0%) of the publications analyzed qualify as highly cited when using the ESI criteria for the top 1% of papers. These publications cover two fieldsEnvironment/Ecology and Geosciencesand these publications are listed in Table 21. Two (16.7%) of the non-journal publications met the top 0.1% threshold in ESI, and one (8.3%) actually met the criteria for the top 0.01% of papers, which is impressive given that the expected numbers of very highly cited non-journal publications for this program are 0.12 and 0.012, respectively, for these thresholds. The citations of the publications that met the criteria for the top 0.1% and 0.01% of papers are presented in Tables 22 and 23.

Table 19. Number of Highly Cited Non-Journal Global Change Publications
by Field (top 10%)


ESI Field

No. of Citations

No. of Publications

Average Cites/Publication

% of Publications in Field

Clinical Medicine

13

1

13.0

50.0%

Environment/Ecology

487

3

162.3

42.9%

Geosciences

150

1

150.0

50.0%

Total = 650

Total = 5

130.0

41.7%

Table 20. Highly Cited Non-Journal Global Change Publications (top 10%)


ESI Field

No. of Cites

Author(s)

Publication

Clinical Medicine

13

Corvalan C, Hales S, McMichael A, Butler C, Campbell-Lendrum D, Confalonieri U, Letiner K, Lewis N, Patz J, Polson K, Scheraga JD, Woodward A, Younes M

Ecosystems and human well-being: health synthesis. Report of the World Health Organization, 2005.

Environment/ Ecology

400

McCarthy JJ, Canziani OF, Leary NA, Dokken DJ, White KS, eds.

Climate Change 2001: Impacts, Adaptation, and Vulnerability. Report of the Intergovernmental Panel on Climate Change, World Meteorological Organization and United Nations Environment Programme. Cambridge, United Kingdom: Cambridge University Press, 2001, 1032 pp.

22

Zepp RG

Solar ultraviolet radiation and aquatic carbon, nitrogen, sulfur and metals cycles (Chapter 5). In: Helbling EW, Zagarese H, eds. Ultraviolet Effects in Aquatic Organisms and Ecosystems. United Kingdom: Royal Society of Chemistry, 2003, pp. 137-184.

65

Marshall P, Schuttenberg H, eds.

A Reef Managers Guide to Coral Bleaching. Townsville, Australia: Great Barrier Reef Marine Park Authority, 2006, 163 pp.

Geosciences

150

Giorgi F, Hewitson B, Christensen J, Hulme M

Regional climate information evaluation and projections (Chapter 10). In: Houghton JT, Ding Y, Griggs DJ, Noguer M, van der Linden PJ, Dai X, Maskell K, Johnson CA, eds. Climate Change 2001: The Scientific Basis. Contribution of Working Group I to the Third Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge, United Kingdom: Cambridge University Press, 2001, pp. 583-638.

Table 21. Highly Cited Non-Journal Global Change Publications (top 1%)


ESI Field

No. of Cites

Author(s)

Publication

Environment/ Ecology

400

McCarthy JJ, Canziani OF, Leary NA, Dokken DJ, White KS, eds.

Climate Change 2001: Impacts, Adaptation, and Vulnerability. Report of the Intergovernmental Panel on Climate Change, World Meteorological Organization and United Nations Environment Programme. Cambridge, United Kingdom: Cambridge University Press, 2001, 1032 pp.

Environment/ Ecology

65

Marshall P, Schuttenberg H, eds.

A Reef Managers Guide to Coral Bleaching. Townsville, Australia: Great Barrier Reef Marine Park Authority, 2006, 163 pp.

Geosciences

150

Giorgi F, Hewitson B, Christensen J, Hulme M

Regional climate information evaluation and projections (Chapter 10). In: Houghton JT, Ding Y, Griggs DJ, Noguer M, van der Linden PJ, Dai X, Maskell K, Johnson CA, eds. Climate Change 2001: The Scientific Basis. Contribution of Working Group I to the Third Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge, United Kingdom: Cambridge University Press, 2001, pp. 583-638.

Table 22. Very Highly Cited Non-Journal Global Change Publications (top 0.1%)


ESI Field

No. of Cites

Author(s)

Publication

Environment/ Ecology

400

McCarthy JJ, Canziani OF, Leary NA, Dokken DJ, White KS, eds.

Climate Change 2001: Impacts, Adaptation, and Vulnerability. Report of the Intergovernmental Panel on Climate Change, World Meteorological Organization and United Nations Environment Programme. Cambridge, United Kingdom: Cambridge University Press, 2001, 1032 pp.

65

Marshall P, Schuttenberg H, eds.

A Reef Managers Guide to Coral Bleaching. Townsville, Australia: Great Barrier Reef Marine Park Authority, 2006, 163 pp.

Table 23. Extremely Highly Cited Non-Journal Global Change Publication (top 0.01%)


ESI Field

No. of Cites

Author(s)

Publication

Environment/ Ecology

65

Marshall P, Schuttenberg H, eds.

A Reef Managers Guide to Coral Bleaching. Townsville, Australia: Great Barrier Reef Marine Park Authority, 2006, 163 pp.

Ratio of Actual Cites to Expected Citation Rates

The expected citation rate is the average number of cites that a paper published in the same journal in the same year and of the same document type (article, review, editorial, etc.) has received from the year of publication to the present. Using the ESI average citation rates for papers published by field as the benchmark, the non-journal global change publications were cited more than the average paper in all 4 fields to which the non-journal global change publications were assigned, i.e., the ratio of actual to expected cites is greater than 1 (see Table 24). For all 4 fields combined, the ratio of total number of cites to the total number of expected cites (720 to 90.09) is 8.0, indicating that the non-journal global change publications are cited more than the average journal paper.

Table 24. Ratio of Actual Cites to Expected Cites for Non-Journal Global Change Publications by Field


ESI Field

Total Cites

Expected Cite Rate

Ratio

Clinical Medicine

36

14.72

2.4

Environment/Ecology

523

48.53

10.8

Geosciences

151

17.30

8.7

Plant & Animal Science

10

9.54

1.0

TOTAL

720

90.09

8.0

III. Analysis of Global Change Publications by Focus Area

This section of the report presents an analysis of the global change papers by focus area (i.e., Air Quality, Human Health, Regional- and Place-Based Assessment, and Water Quality/Aquatic Ecosystem). The data are presented by focus area in Table 25, which includes eight key bibliometric parameters.

The results of the analysis are presented below and the numbers link the findings with the corresponding data in Table 25.

1. No. of Global Change Papers AnalyzedThere were 66 Air Quality, 42 Human Health, 42 Regional- and Place-Based Assessment, and 282 Water Quality/Aquatic Ecosystem publications analyzed. Sixty-five percent of the global change publications fall under the Water Quality/Aquatic Ecosystem focus area.

2. Total No. of Highly Cited PublicationsThis analysis used four of the ESI thresholds for highly cited papersthose in the top 10%, top 1%, top 0.1%, and top 0.01%. It is extraordinary for a publication to meet the threshold for the top 0.01%; these publications are rare and should not be expected in every program. Using the ESI thresholds, about 25% of the global change publications are highly cited papers (this is 2.5 times the number expected). The percentage of global change papers that qualify as highly cited when using the ESI criteria for the top 10% of highly cited publications ranges from 4.8% for the Regional- and Place-Based Assessment papers to 38.1% for the Human Health papers. The Human Health and Water Quality/Aquatic Ecosystem focus areas have the highest percentages of highly cited publications when using the ESI criteria for the top 10%, and the number of highly cited papers in these areas is 3.8 and 2.6 times higher than expected. The Human Health and Water Quality/Aquatic Ecosystem focus areas also hold the lead positions when using the ESI criteria for the top 1% of papers, and the number of very highly cited papers in these areas is 4.8 and 3.2 times higher than expected. Two (0.7%) papers in the Water Quality/Aquatic Ecosystem focus area meet the ESI criteria for the top 0.1% of papers, which is 7 times higher than the expected number. One (0.4%) of the Water Quality/Aquatic Ecosystem papers meets the ESI criteria for the most highly cited papers (top 0.01%), which is extraordinary because the expected number of papers in this top category for a typical program of this size would be 0.03 papers.

3. Ratio of Actual to Expected CitesThe global papers are more highly cited than the average paper. Using the ESI average citation rates for papers published by field as the benchmark, the ratio of actual to expected cites is greater than 1 for all but one of the focus areas (i.e., Regional- and Place-Based Assessment). This indicates that the global change papers are more highly cited than the average papers published in these fields.

4. No. of Papers in High Impact Journals by Impact FactorNearly three-fourths of the Human Health, one-fourth of the Water Quality/Aquatic Ecosystem, and one-sixth of the Air Quality papers are published in high impact journals as determined by the Impact Factor of the journals in which the papers are published. The percentage of papers in high impact journals for the Air Quality, Human Health, and Water Quality/Aquatic Ecosystem focus areas ranges from 15.2% to 73.8% to 22.3%, which is 1.5, 7.4, and 2.2 times higher than expected for these three focus areas, respectively. None of the Regional- and Place-Based Assessment papers are published in high impact journals.

5. No. of Papers in High Impact Journals by Immediacy IndexNearly three-fourths of the Human Health, one-third of the Air Quality, and one-fourth of the Water Quality/Aquatic Ecosystem papers are published in high impact journals as determined by the Immediacy Index of the journals in which the papers are published. The percentage of papers published in high impact journals ranges from 73.8% for Human Health, 30.3% for Air Quality, and 25.2% for Water Quality/Aquatic Ecosystem, which is 7.4, 3.0, and 2.5 times higher than expected for these three focus areas, respectively. Only 2.4% of the Regional- and Place-Based Assessment papers are published in high impact journals as determined by Immediacy Index, which is less than the expected 10%.

6. Total No. of Publications Cited One or More TimesIn all four focus areas, the percentage of publications cited one or more times is very high (i.e., 84.8% to 95.2%).

7. Total No. of Author Self CitesFor three of the four focus areas, the authors of the global change papers cite themselves less than the average self-citation rate. The author self-citation rates for these three focus areas range from 4.0% for Human Health, 4.5% for Regional- and Place-Based Assessment and 4.9% for Water Quality/Aquatic Ecosystem. The rates for these three focus areas are well below the accepted range of 10-30% author self-citation rate, and the rate for the Air Quality papers is 14.3%, which is within the average range.

8. No. of Hot PapersUsing the hot paper thresholds established by ESI as a benchmark, there were hot papers published in three of the four focus areas. The highest percentage of hot papers (i.e., 9.5%) is in the Regional- and Place-Based Assessment focus area, followed by the Air Quality focus area at 3.0% and the Water Quality/Aquatic Ecosystem focus area at 1.8%. These percentages are 95, 30, and 18 times higher than expected for these three focus areas, respectively. None of the Human Health papers qualified as hot papers.

Table 25. Key Bibliometric Parameters for Global Change Papers by Focus Area


ANALYSIS PARAMETERS

Focus Areas

Air Quality

Human Health

Regional- and Place-Based Assessment

Water Quality/ Aquatic Ecosystem

1. No. of Global Change Papers Analyzed

66

42

42

282

2. No. of Highly Cited Publications That Met the Top 10% Threshold (Percentage)

16 (24.2%)

16 (38.1%)

2 (4.8%)

74 (26.2%)

No. of Highly Cited Publications That Met the Top 1% Threshold (Percentage)

1 (1.5%)

2 (4.8%)

0 (0%)

9 (3.2%)

No. of Highly Cited Publications That Met the Top 0.1% Threshold (Percentage)

0 (0%)

0 (0%)

0 (0%)

2 (0.7%)

No. of Highly Cited Publications That Met the Top 0.01% Threshold (Percentage)

0 (0%)

0 (0%)

0 (0%)

1 (0.4%)

3. Expected No. of Citations Calculated Using the Average Citation Rate

201.68

501.04

390.68

2,239.32

Total No. of Times Cited for All Publications

273

980

288

4,384

Ratio of Actual Cites to Expected Cites

1.4

2.0

0.7

2.0

4. No. of Papers in High Impact Journals by Impact Factor
(Percentage)

10 (15.2%)

31(73.8%)

0 (0%)

63 (22.3%)

5. No. of Papers in High Impact Journals by Immediacy Index (Percentage)

20 (30.3%)

31 (73.8%)

1 (2.4%)

71 (25.2%)

6. No. of Publications Cited One or More Times (Percentage)

56 (84.8%)

40 (95.2%)

39 (92.9%)

250 (88.6%)

7. Total No. of Author Self Cites (Percentage)

39 (14.3%)

39 (4.0%)

13 (4.5%)

214 (4.9%)

8. No. of Hot Papers
(Percentage)

2 (3.0%)

0 (0%)

4 (9.5%)

5 (1.8%)

 IV. Additional ESI Parameters for Global Warming Publications

Since the last bibliometric analysis for the Global Change Research Program, which was conducted in 2006, ESI has begun analyzing special topics and reporting information such as the top 20 papers, top 20 authors, top 20 institutions, and top 20 countries for these special topics. One of the of ESI special topics is global warming. The parameters reported by ESI for the special topic of global warming are compared with the results of the analysis of the EPA Global Change Research Program publications below.

Top 20 Papers in Global WarmingA review of ESIs top 20 papers on the topic of global warming (published from January 1, 1996 to April 30, 2006), indicates that 1 (5.0% of the top 20 papers) are papers from EPAs Global Change Research Program. This paper is listed in Table 26.

Top 20 Authors in Global WarmingNone of ESIs top 20 authors in global warming (ranked by total cites from 1996-2006) authored papers for EPAs Global Change Research Program.

Table 26. EPA Global Change Paper in ESIs Top 20 Global Warming Papers Overall
(Published from January 1, 1996 to April 30, 2006)


ESI Rank

EPA Global Change Program Publication

5

Root TL, et al. Fingerprints of global warming on wild animals and plants. Nature 2003;421(6918):57-60.

Top 20 Countries Publishing in Global WarmingThe United States ranks number one among the top 20 countries publishing on global warming. From 1996-2006, the United States published 1,362 papers that were cited 16,682 times. The second ranking country, England, published 447 papers that were cited 6,259 times.

Top 20 Journals in Global Warming100 (23.2%) of the EPA Global Change Research Program papers were published in ESIs top 20 journals in global warming (ranked by total cites from 1996-2006). The top 20 journals and the number of EPA global change published in these journals are provided in Table 27.

Table 27. ESIs Top 20 Journals in Global Warming (Ranked by Total Cites, 1996-2006)


ESI Rank

Journal

Total Cites

Number of Papers

Cites Per Paper

Number of EPA Global Change Papers in Journal

1

Nature

3,409

49

69.57

3

2

Science

2,047

33

62.03

4

3

Geophysical Research Letters

1,210

116

10.43

6

4

Journal of Climate

1,099

70

15.70

9

5

Climatic Change

1,050

90

11.67

20

6

Journal of Geophysical Research-Atmospheres

886

70

12.66

18

7

Proceedings of the National Academy of Sciences of the United States of America

735

28

26.25

4

8

Climate Dynamics

600

35

17.14

1

9

Global Change Biology

440

58

7.59

6

10

Forest Ecology and Management

380

20

19.00

5

11

Global Biogeochemical Cycles

356

27

13.19

2

12

Trends in Ecology & Evolution

344

5

68.80

0

13

Tellus Series B-Chemical and Physical Meteorology

342

16

21.38

1

14

Ambio

328

29

11.31

2

15

Ecology

328

21

15.62

2

16

Environmental Health Perspectives

320

13

24.62

10

17

Quaternary Science Reviews

318

8

39.75

0

18

Geology

282

15

18.80

0

19

Global Change Biology

280

10

28.00

6

20

Bulletin of the American Meteorological Society

259

12

21.58

1

Total

 

 

 

100

Top 20 Institutions Publishing on Global WarmingThe National Aeronautics and Space Administration (NASA) ranks number one on ESIs top 20 overall institutions publishing on global warming with 48 papers (published from 1996-2006) that were cited 1,559 times. NASA is one of the partners on EPA grants that publish under the Global Change Research Program. Thirteen (65.0%) of the top 20 institutions publishing global warming papers are participants in EPAs Global Change Research Program. The top 20 institutions are listed in Table 28.

Table 28. ESIs Top 20 Institutions Publishing on Global Warming
(Ranked by Total Cites, 1996-2006)


ESI Rank

Institution

Total Cites

Number of Papers

Cites Per Paper

Participant in EPAs Global Change Research Program

1

NASA

1,559

48

32.48

Yes

2

NOAA

1,471

49

30.02

No

3

Stanford University

1,014

40

25.35

Yes

4

National Center for Atmospheric Research

927

32

28.97

Yes

5

Pennsylvania State University

884

39

22.67

Yes

6

Columbia University

870

40

21.75

Yes

7

Meteorology Office, Hadley Centre for Climate Change

742

19

39.05

No

8

Rutgers State University

732

25

29.28

Yes

9

MIT

710

51

13.92

Yes

10

University of California-Berkeley

685

50

13.70

Yes

11

Princeton University

674

41

16.44

Yes

12

University of California-San Diego

650

25

26.00

No

13

University of Queensland

633

14

45.21

No

14

University of Maryland

565

24

23.54

Yes

15

U.S. Forest Service

563

20

28.15

Yes

16

Michigan State University

556

16

34.75

No

17

University of Illinois

524

26

20.15

Yes

18

University of East Anglia

504

34

14.82

No

19

Harvard University

488

22

22.18

Yes

20

University of Victoria

487

27

18.04

No

Global Warming Publication TrendsAccording to ESI, the number of global warming papers generally rose from 1996 to 2003; the number of papers declined slightly in 2004 and then increased in 2005 (because the data for 2006 are incomplete, no conclusion can be drawn concerning the trend in 2006). The number of cites of global warming papers published from 1996 to 2000 increased steadily, but has declined for papers published from 2001 to 2005. The trends are depicted in Figure 1. The number of EPA Global Change Research Program publications, however, increased from 1998 to 2000, declined in 2001, peaked in 2002, and leveled off from 2003 to 2006 at an average of 41 publications per year. Like the overall global warming paper trends identified by ESI, the number of cites and the cites per paper for the EPA Global Change Research Program publications have declined significantly in recent years.

Figure 1. Comparison of ESI Global Warming Publication Trends with EPA Global Change Research Program Publication Trends

Comparison of <em>ESI</em> Global Warming Publication Trends  with EPA Global Change Research Program Publication Trends

Comparison of <em>ESI</em> Global Warming Publication Trends  with EPA Global Change Research Program Publication Trends

Comparison of <em>ESI</em> Global Warming Publication Trends  with EPA Global Change Research Program Publication Trends

ESI Field Distribution of Global Warming PapersThe majority of global warming papers from 1996 to 2006 were published in journals that fall within the ESI field of Geosciences, followed by the fields of Environment/Ecology, Engineering, Multidisciplinary, and Social Sciences. For the EPA global change papers included in this analysis, the majority of the papers were published in the ESI field of Environment/Ecology, followed by Geosciences, Multidisciplinary, Plant & Animal Science, and Engineering. The distribution of global warming papers among the 22 ESI fields and the distribution of the EPA global change papers for comparison are presented in Table 29.

Table 29. Comparison of Field Distribution of Global Warming Papers (Ranked by Number of Papers, 1991-2001) to Field Distribution of EPA Global Change Research Program Papers (Published from 1998-2007)


ESI Rank

ESI Field

Global Warming Papers Overall

EPA Global Change Papers

Total Cites

Number of Papers

Cites Per Paper

% of Papers

Total Cites

Number of Papers

Cites Per Paper

% of Papers

1

Geosciences

6,047

516

11.72

18.3%

1,372

87

15.8

20.1%

2

Environment/ Ecology

3,881

485

8.00

17.2%

2,103

175

12.0

40.5%

3

Engineering

649

302

2.15

10.7%

374

47

8.0

10.9%

4

Multidisciplinary

3,371

274

12.30

9.7%

820

12

68.3

2.8%

5

Social Sciences

891

259

3.44

9.2%

41

7

5.8

1.6%

6

Chemistry

399

199

2.01

7.0%

7

Plant & Animal Science

1,834

180

10.19

6.4%

568

65

8.7

15.0%

8

NO CATEGORY

0

169

0

6.0%

9

Economics & Business

730

139

5.25

4.9%

25

2

12.5

0.5%

10

Agricultural Sciences

295

66

4.47

2.3%

8

1

8.0

0.2%

11

Clinical Medicine

159

58

2.74

2.0%

352

16

22.0

3.7%

12

Materials Science

84

49

1.71

1.7%

13

Biology & Biochemistry

318

44

7.23

1.6%

108

10

10.8

2.3%

14

Physics

229

42

5.45

1.5%

4

1

4.0

0.2%

15

Microbiology

62

10

6.20

0.4%

113

6

18.8

1.4%

16

Space Science

16

10

1.60

0.4%

17

Computer Science

25

7

3.57

0.2%

7

1

7.0

0.2%

18

Psychiatry/Psychology

20

6

3.33

0.2%

19

Immunology

0

3

0

0.1%

30

2

15.0

0.5%

20

Molecular Biology & Genetics

14

2

7.00

0.1%

21

Pharmacology & Toxicology

2

2

1.00

0.1%

22

Neuroscience & Behavior

0

1

0

0.0%

Total

 

19,026

2,823

6.74

100%

5,925

432

13.7

100%

1 Thomson Scientifics Web of Science provides access to current and retrospective multidisciplinary information from approximately 8,830 of the most prestigious, high impact research journals in the world. Web of Science also provides cited reference searching.

2 Scopus is a large abstract and citation database of research literature and quality Web sources designed to support the literature research process. Scopus offers access to 15,000 titles from 4,000 different publishers, more than 12,850 academic journals (including coverage of 535 Open Access journals, 750 conference proceedings, and 600 trade publications), 27 million abstracts, 245 million references, 200 million scientific Web pages, and 13 million patent records.

3 Garfield E, Sher IH. New factors in the evaluation of scientific literature through citation indexing. American Documentation 1963;18(July):195-210.

4 MacRoberts MH, MacRoberts BR. Problems of citation analysis: a critical review. Journal of the American Society of Information Science 1989;40(5):342-349.

5 Kavaci N, Misak A. Author self-citation in medical literature. Canadian Medical Association Journal 2004;170(13):1929-1930.

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