January 8, 2008
Bibliometric Analysis
for the U.S. Environmental Protection Agency/Office of
Research and Development's Global Change Research
Program
This is a bibliometric analysis of the papers prepared by intramural and extramural
researchers of the U.S. Environmental Protection Agency's (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 program's
first papers were published in 1998). The journal publications were cited 5,925 times in
the journals covered by Thomson Scientific's Web of Science1 andElsevier's 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 Thomson's 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 Thomson's 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 world's 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 journal's 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,
Thomson Scientific's 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.
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Bibliometric Analysis of Global Change Research Program Journal Articles
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
/. Analysis of Global Change Journal Publications
l. 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
ES/ 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 JCF? Impact Factor,
representing 24.1% of EPA's 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
JCf? Immediacy Index, representing 28.5% of EPA's 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.
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Bibliometric Analysis of Global Change Research Program Journal Articles
SUMMARY OF RESULTS (Continued)
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 world's 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 EPA's Global Change Research Program.
//. Analysis of the Non-Journal Global Change Publications
8. 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
Thomson's Web of Science and Google Scholar.
9. 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.
10. Nearly one-half of the non-journal global change publications are highly cited using the top
10% threshold in ES/. 5 (41.7%) of the global change non-journal publications qualify as highly
cited when using the ES/ criteria for the top 10% of highly cited papers. This is 4.2 times the
number of publications expected to be highly cited.
11. One-fourth of the non-journal publications are highly cited using the top 1 % threshold in
ES/. 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.
12. The non-journal global change publications are cited more than the average paper. Using
the ES/ 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.
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Bibliometric Analysis of Global Change Research Program Journal Articles
SUMMARY OF RESULTS (Continued)
///. Analysis of Global Change Journal Publications by Focus Area
13. 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 ES/ 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 ES/ 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.
14. 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.
15. 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.
16. 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%).
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Bibliometric Analysis of Global Change Research Program Journal Articles
SUMMARY OF RESULTS (Continued)
17. 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.
18. 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.
IV. Comparison ofEPAs Global Change Publications to ESI's Top Global Warming Publication
Parameters
19. EPA's Global Change Research Program includes 1 (5.0%) of ESI's top 20 global
warming papers (published from January 1996 to April 2006).
20. The United States ranks first among the top 20 countries publishing on global warming.
21. Nearly one-fourth of the EPA global change papers were published in ESI's top 20
journals in global warming.
22. Thirteen (65%) of the top 20 institutions publishing on global warming participate in
EPA's Global Change Research Program.
23. 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.
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Bibliometric Analysis of Global Change Research Program Journal Articles
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
Agricultural Sciences
Biology & Biochemistry
Clinical Medicine
Computer Science
Economics & Business
Engineering
Environment/Ecology
Geosciences
Immunology
Microbiology
Multidisciplinary
Physics
Plant & Animal Science
Social Sciences, general
No. of Citations
8
108
352
7
25
374
2,103
1,372
30
113
820
4
568
41
Total = 5,925
No. of Global
Change Papers
1
10
16
1
2
47
175
87
2
6
12
1
65
7
Total = 432
Average Cites/Paper
8.0
10.8
22.0
7.0
12.5
8.0
12.0
15.8
15.0
18.8
68.3
4.0
8.7
5.8
13.7
There are 108 (25.0% of the papers analyzed) highly cited EPA global change papers in 10 of the
14 fields—Clinical Medicine, Computer Science, Economics & Business, Engineering,
Environment/ Ecology, Geosciences, Microbiology, Multidisciplinary, Plant & Animal Science,
and Social Sciences—when 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 fields—Engineering, 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 &
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Bibliometric Analysis of Global Change Research Program Journal Articles
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
Clinical Medicine
Computer Science
Economics & Business
Engineering
Environment/Ecology
Geosciences
Microbiology
Multidisciplinary
Plant & Animal Science
Social Sciences, general
No. of Citations
213
7
23
235
955
1,047
113
820
258
11
Total = 3,682
No. of Papers
3
1
1
9
32
34
4
9
14
1
Total = 108
Average Cites/Paper
71.0
7.0
23.0
26.1
29.8
30.8
28.2
91.1
18.4
11.0
34.1
% of Papers in Field
18.8%
100.0%
50.0%
19.1%
18.3%
39.1%
66.7%
75.0%
21.5%
14.3%
25.0%
Table 3. Number of Highly Cited Global Change Papers by Field (top 1%)
ESI Field
Engineering
Environment/Ecology
Geosciences
Microbiology
Multidisciplinary
Plant & Animal Science
No. of
Citations
75
125
227
41
640
6
Total =
1,114
No. of
Papers
1
1
4
1
4
1
Total =
12
Average
Cites/Paper
75.0
125.0
56.8
41.0
160.0
6.0
92.8
% of Global
Change
Papers in
Field
2.1%
0.6%
4.6%
16.7%
33.3%
1.5%
2.8%
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Bibliometric Analysis of Global Change Research Program Journal Articles
Table 4. Highly Cited Global Change Papers in the Field of Engineering (top 1%)
No. of
Cites
75
ESI
Threshold
46
First Author
Douglas EM
Paper
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
125
ESI
Threshold
82
First
Author
Marsh DM
Paper
Metapopulation dynamics and amphibian conservation. Conservation
fl/o/ogy2001;15(l):40-49.
Table 6. Highly Cited Global Change Papers in the Field of Geosciences (top 1%)
No. of
Cites
96
113
12
6
ESI
Threshold
89
89
10
4
First Author
Chase TN
Moran MA
Howarth RW
WuSL
Paper
Simulated impacts of historical land cover changes on global climate in
northern winter. Climate Dynamics 2000;16(2-3):93-105.
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.
Nitrogen as the limiting nutrient for eutrophication in coastal marine
ecosystems: evolving views over three decades. Limnology and
Oceanography 2006;51(l):364-376.
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.
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Bibliometric Analysis of Global Change Research Program Journal Articles
Table 8. Highly Cited Global Change Papers in the Field of Multidisciplinary (top 1%)
No. of
Cites
57
94
448
41
ESI
Threshold
51
57
82
27
First Author
Brutsaert W
Pascual M
Root TL
WormB
Paper
Hydrologic cycle explains the evaporation paradox. Nature
1998;396(6706):30-30.
Cholera dynamics and El Nino-Southern Oscillation. Science
2000;289(5485): 1766-1769.
Fingerprints of global warming on wild animals and plants. Nature
2003;421(6918):57-60.
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
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
Multidisciplinary
Plant & Animal Science
No. of
Citations
448
6
Total =
454
No. of
Papers
1
1
Total =
2
Average
Cites/Paper
448.0
6.0
227.0
% of Global
Change
Papers in
Field
8.3%
1.5%
0.5%
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Bibliometric Analysis of Global Change Research Program Journal Articles
Table 11. Very Highly Cited Global Change Papers (top 0.1%)
ESI Field
Multidisciplinary
Plant & Animal
Science
ESI
Threshold
339
3
No of
Cites
448
6
First Author
Root TL
Bullard SG
Paper
Fingerprints of global warming on wild animals and plants.
Nature 2003;421(6918):57-60.
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
Multidisciplinary
ESI
Threshold
339
No. of
Cites
448
First Author
Root TL
Paper
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
Agricultural Sciences
Biology & Biochemistry
Clinical Medicine
Computer Science
Economics & Business
Engineering
Environment/Ecology
Total
Cites
8
108
352
7
25
374
2,103
Expected Cite
Rate
9.13
114.85
207.45
1.65
6.01
197.85
1,616.28
Ratio
0.9
0.9
1.7
4.2
4.2
1.9
1.3
10
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Bibliometric Analysis of Global Change Research Program Journal Articles
ESI Field
Geosciences
Immunology
Microbiology
Multidisciplinary
Physics
Plant & Animal Science
Social Sciences, general
TOTAL
Total
Cites
1,372
30
113
820
4
568
41
5,925
Expected Cite
Rate
598.58
42.60
103.22
41.87
6.83
362.94
23.46
3,332.72
Ratio
2.3
0.7
1.1
19.6
0.6
1.6
1.7
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 journal's 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
4
3
4
1
4
1
Journal
Science
Nature
Lancet
JAMA-Journal of the American Medical Association
Proceedings of the National Academy of Sciences of the
United States of America
British Medical Journal
Impact
Factor
(IF)
30.028
26.681
25.800
23.175
9.643
9.245
JCR IF
Rank
9
15
18
23
116
128
11
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Bibliometric Analysis of Global Change Research Program Journal Articles
Global
Change
Papers in
that Journal
1
10
2
1
1
1
1
1
2
1
2
6
2
2
6
2
8
1
2
3
1
9
9
1
1
1
8
1
Journal
Reviews of Geophysics
Environmental Health Perspectives
Bioscience
Journal of Infectious Diseases
American Journal of Epidemiology
Emerging Infectious Diseases
Trends in Parasitology
Frontiers in Ecology and the Environment
Ecology
Atmospheric Chemistry and Physics
Epidemiology
Global Change Biology
New Phytologist
Plant Cell and Environment
Environmental Science & Technology
Global Biogeochemical Cycles
Conservation Biology
Bulletin of the American Meteorological Society
American Journal of Public Health
Applied and Environmental Microbiology
Journal of Power Sources
Ecological Applications
Journal of Climate
Climate Dynamics
Oecologia
Global Ecology and Biogeography
Limnology and Oceanography
Microbes and Infection
Impact
Factor
(IF)
8.375
5.861
5.424
5.363
5.241
5.094
4.907
4.842
4.782
4.362
4.339
4.339
4.245
4.135
4.040
3.796
3.762
3.728
3.698
3.532
3.521
3.470
3.419
3.344
3.333
3.314
3.287
3.127
JCR IF
Rank
144
255
291
298
308
332
356
371
381
449
452
452
474
495
518
587
601
614
626
682
686
708
728
747
753
764
774
833
12
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Bibliometric Analysis of Global Change Research Program Journal Articles
Global
Change
Papers in
that Journal
1
Total = 104
Journal
Remote Sensing of Environment
Impact
Factor
(IF)
3.064
JCR IF
Rank
855
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
1
4
3
4
1
4
2
2
2
9
1
1
1
Journal
JAMA- Journal of the American Medical Association
Lancet
Nature
Science
British Medical Journal
Proceedings of the National Academy of Sciences of the
United States of America
Ambio
Journal of the North American Benthological Society
Epidemiology
Journal of Climate
Journal of Infectious Diseases
Emerging Infectious Diseases
Reviews of Geophysics
Immediacy
Index
(II)
7.781
7.419
6.789
5.555
4.412
1.758
1.695
1.568
1.437
1.343
1.300
1.222
1.100
JCR II
Rank
4
6
9
16
25
126
136
158
187
206
221
243
300
13
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Bibliometric Analysis of Global Change Research Program Journal Articles
Global
Change
Papers in that
Journal
1
1
10
2
3
2
1
1
8
8
2
1
2
2
2
18
1
6
2
2
6
1
3
1
2
Total = 123
Journal
American Journal of Epidemiology
Atmospheric Chemistry and Physics
Environmental Health Perspectives
New Phytologist
Journal of Biogeography
Marine Chemistry
Trends in Parasitology
Global Ecology and Biogeography
Limnology and Oceanography
Conservation Biology
Plant Cell and Environment
Climate Dynamics
American Journal of Public Health
Ecology
Global and Planetary Change
Journal of Geophysical Research-Atmospheres
Agricultural and Forest Meteorology
Global Change Biology
Monthly Weather Review
Global Biogeochemical Cycles
Environmental Science & Technology
Bulletin of the American Meteorological Society
Applied and Environmental Microbiology
Environmental Research
Bioscience
Immediacy
Index
(II)
1.091
1.015
0.994
0.970
0.958
0.958
0.906
0.793
0.784
0.778
0.777
0.760
0.740
0.724
0.709
0.684
0.669
0.660
0.654
0.652
0.646
0.646
0.634
0.583
0.582
JCRll
Rank
306
350
373
381
391
391
417
529
537
543
547
569
588
610
635
673
690
705
716
720
729
729
751
844
848
14
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Bibliometric Analysis of Global Change Research Program Journal Articles
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 shorter—papers 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 fields—Engineering, 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
Engineering
Environment/
Ecology
Environment/
Ecology
Geosciences
Multidisciplinary
ESI Hot
Papers
Threshold
4
5
5
5
3
3
3
10
No. of Cites
in 2-Month
Period
6 cites in July-
August 2002
5 cites in May
2000
5 cites in May
2000
8 cites in May
2000
3 cites in
January-
February 2003
4 cites in
November-
December
2004
3 cites in May
2007
19 cites in
September-
October 2004
Paper
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.
Rose A, et al. Simulating the economic impacts of climate
change in the Mid-Atlantic Region. Climate Research
2000;14(3):175-183.
Fisher A, et al. The Mid-Atlantic Regional Assessment:
motivation and approach. Climate Research
2000;14(3):153-159.
Polsky C, et al. The Mid-Atlantic Region and its climate:
past, present, and future. Climate Research 2000;14(3): 161-
173.
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.
Hogrefe C, et al. Simulating regional-scale ozone
climatology over the eastern United States: model
evaluation results. Atmospheric Environment
2004;38(17):2627-2638.
Wu SL, et al. Why are there large differences between
models in global budgets of tropospheric ozone? Journal of
Geophysical Research-Atmospheres 2007; 1 12(D5): Art No.
D05302.
Root TL, et al. Fingerprints of global warming on wild
animals and plants. Nature 2003 ;42 1(69 18): 5 7-60.
15
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Bibliometric Analysis of Global Change Research Program Journal Articles
Field
Multidisciplinary
Plant & Animal
Science
ESI Hot
Papers
Threshold
6
4
4
No. of Cites
in 2-Month
Period
15 cites in
June-July
2007
5 cites in
December
2002
6 cites in
March 2007
Paper
Worm B, et al. Impacts of biodiversity loss on ocean
ecosystem services. Science 2006;314(5800):787-790.
Sousounis PJ, Grover EK. Potential future weather patterns
over the Great Lakes region. Journal of Great Lakes
Research 2002;28(4):496-520.
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-cites—a 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 Thomson's 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
world's 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.
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.
16
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Bibliometric Analysis of Global Change Research Program Journal Articles
Table 17. Highly Cited Researchers Authoring Global Change Publications
Highly Cited
Researcher
Ankley, Gerald T
Brown, Sandra L
Caldwell, Martyn M
Callaghan, Terry V
Chase, Thomas N
Colwell, Rita R
Ehleringer, James
Elliott, Edward T
Galloway, James Neville
Giorgi, Filippo
Goldberg, Richard
Howarth, Robert W
Jacob, Daniel J
Lauenroth, William K
Levin Simon A
Logan Jennifer A
Lugo, Ariel E
McKenzie Dan
Ojima, Dennis S
Palmer, T.N.
Parton, William J
Pielke, Roger A
Rind, David H
Running, Steven W
Sala, Osvaldo E
Schimel, David S
Schindler David W
Schwartz, Joel D
Seinfeld John H
Shugart, Herman H
Teramura, Alan H
Affiliation
U.S. EPA
Winrock International
Utah State University
University of Sheffield
NINDS
Canon U.S. Life Sciences
University of Utah
University of Nebraska
University of Virginia
Abdus Salam International
Centre for Theoretical Physics
Columbia University
Cornell University
Harvard University
Colorado State University
Princeton University
Harvard University
USDA
University of Cambridge
Colorado State University
European Center for Medium
Range Weather Forecasts
Colorado State University
Colorado State University
NASA Goddard
University of Montana
Brown University
National Center for Atmospheric
Research
University of Alberta
Harvard University
California Institute of Technology
University of Virginia
University of Hawaii
ESI Field
Environment/Ecology
Environment/Ecology
Environment/Ecology
Environment/Ecology
Neuroscience
Microbiology
Environment/Ecology
Environment/Ecology
Environment/Ecology
Geosciences
Engineering
Geosciences
Plant & Animal Science
Environment/Ecology
Geosciences
Environment/Ecology
Environment/Ecology
Geosciences
Environment/Ecology
Geosciences
Environment/Ecology
Geosciences
Environment/Ecology
Geosciences
Geosciences
Environment/Ecology
Environment/Ecology
Environment/Ecology
Environment/Ecology
Environment/Ecology
Engineering
Geosciences
Environment/Ecology
Plant & Animal Science
17
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Bibliometric Analysis of Global Change Research Program Journal Articles
Highly Cited
Researcher
WangJ
Zeger, Scott L
Zepp, Richard G
Total = 34
Affiliation
U.S. National Weather Service,
National Centers for
Environmental Prediction
Johns Hopkins University
U.S. EPA
ESI Field
Geosciences
Mathematics
Environment/Ecology
Patents
There were no patents issued to investigators from 1998 to 2007 for research that was conducted
under EPA's 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 EPA's Global Change Research Program. For this
analysis, 12 non-journal publications—4 reports, 5 books, 2 book chapters, and 1 technical
paper—were reviewed. These publications were published from 2000 to 2007, and they were
cited 720 times in the journals and books covered by Thomson Scientific's 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
Thomson's 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 Thomson's 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.
18
-------
Bibliometric Analysis of Global Change Research Program Journal Articles
Table 18. Non-Journal Global Change Publications by £37 Fields
ESI Field
Clinical Medicine
Environment/Ecology
Geosciences
Plant & Animal Science
No. of
Citations
36
523
151
10
Total = 720
No. of EPA
Publications
2
7
2
1
Total = 12
Average Cites/
Publication
18.0
74.7
75.5
10.0
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 fields—Clinical Medicine, Environment/Ecology, and
Geosciences—when 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 fields—Environment/Ecology and
Geosciences—and 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
Clinical Medicine
Environment/Ecology
Geosciences
No. of Citations
13
487
150
Total = 650
No. of
Publications
1
3
1
Total = 5
Average
Cites/Publication
13.0
162.3
150.0
130.0
% of Publications
in Field
50.0%
42.9%
50.0%
41.7%
19
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Bibliometric Analysis of Global Change Research Program Journal Articles
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, Poison 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 Manager's 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,
1032pp.
20
-------
Bibliometric Analysis of Global Change Research Program Journal Articles
ESI Field
No. of
Cites
Author(s)
Publication
Environment/
Ecology
65
Marshall P, Schuttenberg
H, eds.
A Reef Manager's 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
Environment/
Ecology
No. of
Cites
400
65
Author(s)
McCarthy JJ, Canziani
OF, Leary NA, Dokken
DJ, White KS, eds.
Marshall P, Schuttenberg
H, eds.
Publication
Climate Change 200 1 : 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,
1032pp.
A Reef Manager's 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
Environment/
Ecology
No. of
Cites
65
Author(s)
Marshall P, Schuttenberg
H, eds.
Publication
A Reef Manager's 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
21
-------
Bibliometric Analysis of Global Change Research Program Journal Articles
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
Clinical Medicine
Environment/Ecology
Geosciences
Plant & Animal Science
TOTAL
Total
Cites
36
523
151
10
720
Expected Cite
Rate
14.72
48.53
17.30
9.54
90.09
Ratio
2.4
10.8
8.7
1.0
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 Analyzed—There 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 Publications—This analysis used four of the ESI thresholds for
highly cited papers—those 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
22
-------
Bibliometric Analysis of Global Change Research Program Journal Articles
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 Cites—The 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 Factor—Nearly 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 Index—Nearly 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 Times—In 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 Cites—For 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 Papers—Using 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
23
-------
Bibliometric Analysis of Global Change Research Program Journal Articles
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
1. No. of Global Change Papers
Analyzed
2. No. of Highly Cited
Publications That Met the Top
10% Threshold (Percentage)
No. of Highly Cited
Publications That Met the Top
1% Threshold (Percentage)
No. of Highly Cited
Publications That Met the Top
0.1% Threshold (Percentage)
No. of Highly Cited
Publications That Met the Top
0.01% Threshold (Percentage)
3. Expected No. of Citations
Calculated Using the Average
Citation Rate
Total No. of Times Cited for
All Publications
Ratio of Actual Cites to
Expected Cites
4. No. of Papers in High Impact
Journals by Impact Factor
(Percentage)
5. No. of Papers in High Impact
Journals by Immediacy Index
(Percentage)
6. No. of Publications Cited One
or More Times (Percentage)
7. Total No. of Author Self Cites
(Percentage)
8. No. of Hot Papers
(Percentage)
Focus Areas
Air Quality
66
16 (24.2%)
1 (1.5%)
0 (0%)
0 (0%)
201.68
273
1.4
10(15.2%)
20 (30.3%)
56 (84.8%)
39(14.3%)
2(3.0%)
Human Health
42
16(38.1%)
2 (4.8%)
0 (0%)
0 (0%)
501.04
980
2.0
31(73.8%)
31 (73.8%)
40 (95.2%)
39 (4.0%)
0 (0%)
Regional- and
Place-Based
Assessment
42
2 (4.8%)
0 (0%)
0 (0%)
0 (0%)
390.68
288
0.7
0 (0%)
1 (2.4%)
39 (92.9%)
13 (4.5%)
4 (9.5%)
Water Quality/
Aquatic
Ecosystem
282
74 (26.2%)
9 (3.2%)
2 (0.7%)
1 (0.4%)
2,239.32
4,384
2.0
63 (22.3%)
71 (25.2%)
250 (88.6%)
214 (4.9%)
5 (1.8%)
24
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Bibliometric Analysis of Global Change Research Program Journal Articles
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 Warming—A review ofESFs 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 EPA's Global Change Research Program. This paper is listed in Table
26.
Top 20 Authors in Global Warming—None of ESP s top 20 authors in global warming (ranked
by total cites from 1996-2006) authored papers for EPA's Global Change Research Program.
Table 26. EPA Global Change Paper in ESPs Top 20 Global Warming Papers Overall
(Published from January 1,1996 to April 30, 2006)
ESI Rank
5
EPA Global Change Program Publication
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 Warming—The 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 Warming—100 (23.2%) of the EPA Global Change Research
Program papers were published inESFs 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. ESPs Top 20 Journals in Global Warming (Ranked by Total Cites, 1996-2006)
ESI
Rank
1
2
3
4
Journal
Nature
Science
Geophysical Research Letters
Journal of Climate
Total
Cites
3,409
2,047
1,210
1,099
Number
of
Papers
49
33
116
70
Cites Per
Paper
69.57
62.03
10.43
15.70
Number of
EPA Global
Change
Papers in
Journal
3
4
6
9
25
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Bibliometric Analysis of Global Change Research Program Journal Articles
ESI
Rank
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
Total
Journal
Climatic Change
Journal of Geophysical Research-
Atmospheres
Proceedings of the National Academy
of Sciences of the United States of
America
Climate Dynamics
Global Change Biology
Forest Ecology and Management
Global Biogeochemical Cycles
Trends in Ecology & Evolution
Tellus Series B-Chemical and
Physical Meteorology
Ambio
Ecology
Environmental Health Perspectives
Quaternary Science Reviews
Geology
Global Change Biology
Bulletin of the American
Meteorological Society
Total
Cites
1,050
886
735
600
440
380
356
344
342
328
328
320
318
282
280
259
Number
of
Papers
90
70
28
35
58
20
27
5
16
29
21
13
8
15
10
12
Cites Per
Paper
11.67
12.66
26.25
17.14
7.59
19.00
13.19
68.80
21.38
11.31
15.62
24.62
39.75
18.80
28.00
21.58
Number of
EPA Global
Change
Papers in
Journal
20
18
4
1
6
5
2
0
1
2
2
10
0
0
6
1
100
Top 20 Institutions Publishing on Global Warming—The National Aeronautics and Space
Administration (NASA) ranks number one onESFs 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
EPA's Global Change Research Program. The top 20 institutions are listed in Table 28.
26
-------
Bibliometric Analysis of Global Change Research Program Journal Articles
Table 28. ESPs Top 20 Institutions Publishing on Global Warming
(Ranked by Total Cites, 1996-2006)
ESI
Rank
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
Institution
NASA
NOAA
Stanford University
National Center for
Atmospheric Research
Pennsylvania State University
Columbia University
Meteorology Office, Hadley
Centre for Climate Change
Rutgers State University
MIT
University of California-
Berkeley
Princeton University
University of California-San
Diego
University of Queensland
University of Maryland
U.S. Forest Service
Michigan State University
University of Illinois
University of East Anglia
Harvard University
University of Victoria
Total
Cites
1,559
1,471
1,014
927
884
870
742
732
710
685
674
650
633
565
563
556
524
504
488
487
Number
of
Papers
48
49
40
32
39
40
19
25
51
50
41
25
14
24
20
16
26
34
22
27
Cites Per
Paper
32.48
30.02
25.35
28.97
22.67
21.75
39.05
29.28
13.92
13.70
16.44
26.00
45.21
23.54
28.15
34.75
20.15
14.82
22.18
18.04
Participant in
EPA's Global
Change Research
Program
Yes
No
Yes
Yes
Yes
Yes
No
Yes
Yes
Yes
Yes
No
No
Yes
Yes
No
Yes
No
Yes
No
Global Warming Publication Trends—According 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.
27
-------
Bibliometric Analysis of Global Change Research Program Journal Articles
Figure 1. Comparison of ESI Global Warming Publication Trends with EPA Global
Change Research Program Publication Trends
600-t
200-
100-
0-
i
1
[
•
. . _
!
;;i
n ESI Papers
• EPA Papers
5000-j
ACf\f\
4500-
4000-
3000-
2500-
2000-
1000-
Cf\f\
500-
0-
1
m
n
1
Ln.^
D ESI Cites
• EPA Cites
N^
^
25-
A e
TO'
10-
•
0.
^0
.
? ^
r
f
if if
Jl
DESI Cites/Paper
• EPA Cites/Paper
28
-------
Bibliometric Analysis of Global Change Research Program Journal Articles
ESI Field Distribution of Global Warming Papers—The majority of global wanning 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
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
Total
ESI Field
Geosciences
Environment/ Ecology
Engineering
Multidisciplinary
Social Sciences
Chemistry
Plant & Animal Science
NO CATEGORY
Economics & Business
Agricultural Sciences
Clinical Medicine
Materials Science
Biology & Biochemistry
Physics
Microbiology
Space Science
Computer Science
Psychiatry/Psychology
Immunology
Molecular Biology &
Genetics
Pharmacology &
Toxicology
Neuroscience & Behavior
Global Warming Papers Overall
Total
Cites
6,047
3,881
649
3,371
891
399
1,834
0
730
295
159
84
318
229
62
16
25
20
0
14
2
0
19,026
Number
of
Papers
516
485
302
274
259
199
180
169
139
66
58
49
44
42
10
10
7
6
3
2
2
1
2,823
Cites
Per
Paper
11.72
8.00
2.15
12.30
3.44
2.01
10.19
0
5.25
4.47
2.74
1.71
7.23
5.45
6.20
1.60
3.57
3.33
0
7.00
1.00
0
6.74
%of
Papers
18.3%
17.2%
10.7%
9.7%
9.2%
7.0%
6.4%
6.0%
4.9%
2.3%
2.0%
1.7%
1.6%
1.5%
0.4%
0.4%
0.2%
0.2%
0.1%
0.1%
0.1%
0.0%
100%
EPA Global Change Papers
Total
Cites
1,372
2,103
374
820
41
—
568
—
25
8
352
—
108
4
113
—
7
—
30
—
—
—
5,925
Number
of
Papers
87
175
47
12
7
—
65
—
2
1
16
—
10
1
6
—
1
—
2
—
—
—
432
Cites
Per
Paper
15.8
12.0
8.0
68.3
5.8
—
8.7
—
12.5
8.0
22.0
—
10.8
4.0
18.8
—
7.0
—
15.0
—
—
—
13.7
%of
Papers
20.1%
40.5%
10.9%
2.8%
1.6%
—
15.0%
—
0.5%
0.2%
3.7%
—
2.3%
0.2%
1.4%
—
0.2%
—
0.5%
—
—
—
100%
This bibliometric analysis was prepared by
Beverly Campbell, The Scientific Consulting Group, Inc.
under EPA Contract No. EP-C-05-015
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