Bibliometric Analysis of Climate Change Articles on SCI Journal

This research used Bibliometric and spatial distribution to describe science research productivities of climate change articles on SCI during 2007-2018. Of 25278 articles on climate change field, total research publication and Article form is increasing from 2007 to 2018; gains 3325 articles of total scientific production; 2800 articles of Article form in 2018 year. Moreover, the Article form is the highest research production as well with 19917 articles (1 st ranking). The USA has the highest publication in all the article types and total research productivity (23286 articles with 1 st ranking) including 5369 independent articles (23.06%) and 17917 collaborative articles (76.94%). CLIMATIC CHANGE journal has the most research output with 1105 articles (4.37%) and 1 st ranking. Vietnam is ranked 45 th with 159 articles (0.63%) including 33 independent articles (50 th ranking, 20.8%) and 126 collaborative articles (44 th ranking, 79.2%). Further, research productivity is also revealed all the countries with different research productivity quantities on the world map as USA, Canada, Europe community, and some Asia countries has high publication. Particular, Independent publication is showed from small red round dot to big one, and cooperative publication is performed in different colors, in which USA has the most publication in dark blue and big red dot. Therefore, this paper revealed science growth, research publishing trend, and spatial distribution of countries on climate change articles, and it also provides knowledge as well as more understanding about climate change field.


Introduction
The past decade has demonstrated that the global environment has been altered by human activities (CGCR, 1999).Climate change refers to a change in the state of the climate that can be identified by changes in the mean and/or the variability of its properties and that persists for an extended period, typically decades or longer (IPCC, 2007).It is attributed directly or indirectly to human activity that alters the composition of the global atmosphere such as the burning of fossil fuels (CGCR, 1999), land use change and agriculture that are increasing the atmospheric concentrations of greenhouse gases, and aerosols (IPCC, 1995).This change is precisely temperature change, precipitation, humidity, wind patterns (IPCC, 2001) and they make alteration of the energy balance of the climate system led to increase risk of vector born diseases, widespread damage of natural ecosystem, loss of biodiversity, increase the frequency of extreme events like droughts, floods (AASA, 2011), typhoon, heat wave, wildfire (Ken Ogilvie et al., 2004;Susanne C. Moser et al., 2007).According to the recent Intergovernmental Panel on Climate Change reported, the average global surface temperature has increased by 0.74 C over the last 100 years   (IPCC, 2007), it is caused by the build-up of greenhouse gases in the atmosphere accumulated from continual combustion of fossil fuels (Hatzigeorgiou et al., 2008) and warmer temperatures will lead to a more vigorous hydrological cycle; this translates into prospects for more severe droughts and/or floods in some places and less severe droughts and/or floods in other places (IPCC, 1995) concurrently increasing in global average air and ocean temperatures, widespread melting of snow and ice and rising global average sea level (IPCC 2007).Consequently, global sea level has risen by between 10 and 25 cm over the past 100 years (IPCC, 1995), leads to affect freshwater flows with dramatic adverse effects on biodiversity, people and livelihoods (Jinghai Li et al., 2011).Therefore, climate change has become a major scientific, political, economic, and environmental issue during the last decade (Li et al, 2011) and scientific articles on climate change have demonstrated a rapid increase in quantity over the past several decades, a number of papers presenting the latest research achievements have been published in authoritative scientific journals such as Nature and Science (Jinfeng Li et al, 2011).And bibliometric is a research tool, regarded as cannot be absent in the investigation of the information science field because of its strength in quantitative (Almind and Ingwersen, 1997) and qualitative analysis (Zhang et al, 2010) to improve efficiency rates of information handling process (Ashwini tiwari, 2006) and increase understanding of the information science research (Gayatri mahapatra, 2009).Therefore, in this research based on 25278 articles, which were published on SCI from 2007 to 2028 year to find out a new method as calculation of research publications and spatial distribution of countries on the world map.Particular, the research aims to 1) describe and analyze total research productivity in 2007-2018, research productivity of article types, journals of climate change articles.2) Analyze research publication of countries and perform its distribution on the world map.This can be helped authorizes to be easily in envision about climate change scientific productivity on the world.

Methodology
The whole data source was download from Science Citation Index (SCI) database from 2007 to 2018 with term "climate* change*" including "climate changes", "climatic change", "climate change", and "climatic changes".It was used to locate publication containing these words in parts of titles, abstracts or keywords.After that, these 25278 articles were recorded and calculated into spreadsheet Excel with different types as article types, country, journal, and so on.
As common as other bibliometric method, before calculating total research productivities needs to implement some steps as group all the articles originated from England, Scotland, North Ireland, Wales were United Kingdom (UK) heading; the articles are from different States of America are reclassified as United State America (USA).Peoples R China, Taiwan, Hong Kong are belonged to be China.Collaborative categories are determined when independent categories are assigned.Independent categories include one or many common authors which are designed researcher.Collaborative categories conclude many different authors from one or multiple countries.

Results and discussion
Total 25278 articles were derived from Science Citation Index database to calculate and analyze research publication in period 2007-2018.The results are presented as follow: year 64 articles -this vision seems contrast with growth rule of research publication on SCI.From the figure 1 presents three growth lines of scientific productivity on total research productivity, article, and review type, in which next year is almost more published than last year, especially the scientific production increases sharp from 2007 to 2011 (905 articles to 2035 articles) and from 2017 to 2018 (2711 articles to 3325 articles) on climate change articles in article and total research productivity.However, in review type, scientific publication increases from 2007 to 2018, but that increasing is only slowly, approximately 400 articles in 2018.

Article types
Article types are one in many science information categories which can be counted by bibliometric.They include many forms and table 1 is   Besides, the table 2 can be seen that division of research production in each year in 2007-2018.It indicates some journals grow in publication output and increase sharply in the last years (2017 and 2018 year), such as CLIMATIC CHANGE journal (1 st ranking), ENVIRONMENTAL RESEARCH LETTERS journal (10 th ranking); and SCIENCE OF THE TOTAL ENVIRONMENT journal (5 th ranking).Contrast, there are three journals, which have diminished in the last year as REGIONAL ENVIRONMENTAL CHANGE journal (4 th ranking), PLOS ONE journal (3 rd ranking), and GLOBAL ENVIRONMENTAL CHANGE journal (7 th ranking).Moreover, there are not or very less publication output (0-6 articles in 2007-2010 year) in some journals of climate change articles as REGIONAL ENVIRONMENTAL CHANGE journal, SCIENCE OF THE TOTAL ENVIRONMENT journal, and NATURE CLIMATE CHANGE journal.But they reveal high publication output in many next years.This means climate change field has an important signification on the world and be paid attention by scientists.3 includes top 20 countries have the highest publication output and Vietnam is a country, which is 45 th ranking.It indicates that USA is 1 st ranking with research output as 23286 articles (24.29%) concluding 5369 independent articles (23.06%) and 17917 collaborative articles (76.94%).The 2 nd ranking is China with 8782 articles (9.16%), whereas has 2241 independent articles (25.52%) and 6541 collaborative article (74.48%).United Kingdom is ranked the third with 8051 articles (8.4%), in which 2023 independent articles (25.13%) and 6028 collaborative articles (74.87%).The ranking list is followed by Australia 6153 articles (4 th ranking with 6.42%); Germany 5079 articles (5 th ranking, 5.3%); Canada (6 th ranking with 5.07%); France 3365 articles (7 th ranking, 3.51%); Spain 2701 articles (8 th ranking, 2.82%); Italy 2473 articles (9 th ranking, 2.58%); Netherlands 2164 articles (10 th ranking, 2.26%); India; Switzerland; Japan; Sweden; Brazil; Norway; South Korea; Denmark; South Africa; and Finland have research productivity from 974 articles (1.02%) to 2105 articles (2.2%) at the 11 th -20 th ranking.Finally, in the below ranking table is Vietnam with 159 articles (45 th ranking, 0.63%) including 33 independent articles (50 th ranking, 20.8%) and 126 collaborative articles (44 th ranking, 79.2%).
Besides, in the table 3 can be seen clearly that 8 countries are always top ranking in total research production, independent article and collaborative article as USA, China, UK, Australia, Germany, Canada, France, and Spain.Next is Italy (9 th ranking), it has independent article number (10 th ranking) less than India.Although India is the 9 th ranking in independent articles, but it is ranked the 11 th in collaborative article and total publication output categories.Moreover, Japan and Sweden often exchange ranking with each other (13 th and 14 th ranking) in all three kinds of research output.This exchange ranking also happens in research productivity of Norway, South Korea, and Denmark (16 th , 17 th , 18 th ranking).Some countries have not any ranked changing about research outputs as Switzerland, Brazil, South Africa, and Finland (12 th , 15 th , 19 th , and 20 th ranking).Thus, distribution of research productivity by countries demonstrated that USA where had the highest research publication and ranking in all three kinds of research output; Vietnam ranks the 45 th with 159 articles.
And below figure 2 presents spatial distribution of independent and collaborative articles via countries on the world shows that research productivity is almost published on all the countries.Which country has big red round dot, it means the scientific productivity in that country is a lot, where as USA has the most research publication.Contrast, which country has small red round dot, it means that country has a few research publications, even there are some countries have very few research output.On the world map shows the countries, which have a lot of research publication almost belongs to USA and Europe country community; a few ones are in Asia countries.Left ones are low research publication.Moreover, the figure 2 also shows the independent article number and cooperative article number belong to USA in big red round dot and dark blue color.The countries have few research output is revealed by small red round dot and light blue color (0-309 articles in cooperated output and 0-119 article in independent output).The countries are second ranked after USA belongs to China, Australia, Canada, etc. India has 1439 cooperative articles, is performed by light pink color on the world map.Thus, spatial distribution of research publication is divided by 5 classes.In independent publication, 0-119 articles is 1 st class, 120-377 articles is 2 nd class, 378-702 articles is 3 rd class, 703-2241 articles is 4 th class, and the last class includes 2242-5369 articles, the class has the most research publication.In cooperative publication has 5 classes as well and is distributed by 5 color kinds, from light blue, yellow, light pink, green, and dark blue, in which the dark blue has the most research publication on climate change articles from 2007 to 2018 year.

Conclusion
From 25278 articles published on SCI during 2007-2018, analysis of research productivity provided to be more understanding about climate change field, knowledge deeply of calculation in publication output in many years, some significant points in this research are drawn following as: Total research productivity increases in yearly and increases sharply in 2018 year, gains to 3325 articles, in which Article form also grows continuously to 2018 year and achieves about 2800 articles in 2018.Moreover, Article form is the highest research production as well with 19917 articles (1 st ranking).USA is a country, where has the highest publication output in all the article types and in total research productivity (23286 articles with 1 st ranking).It includes 5369 independent articles (23.06%) and 17917 collaborative articles (76.94%).CLIMATIC CHANGE journal has the most research output with 1105 articles (4.37%), 1 st ranking, and it increases sharply in the last years.NATURE CLIMATE CHANGE journal has not any research output in first years of publication period, but its publication grows highly in next year.Besides, there are 163 countries are found in climate change article publication and spatial distribution of research productivity is performed on the world map.The research productivity is almost revealed on all the countries with different scientific productivity quantities; they are classed 5 kinds from low to high publication.Particular, Independent publication is showed from small red round dot to big one, and cooperative publication is performed in different colors, in which USA has the most publication in dark blue and big red dot.Moreover, the countries have high publication most belong to USA, Canada, Europe country community, and some Asia countries as China, India.Vietnam is performed by light blue color with 159 articles in total research publication (45 th ranking, 0.63%), concluding 33 independent articles (50 th ranking, 20.8%) and 126 collaborative articles (44 th ranking, 79.2%).

3. 4
Distribution of country In calculation of climate change articles on SCI, country category gives us to be known which countries have independent articles or collaborative articles and its research productivity.Via 25278 articles, this research found out 163 countries published climate change articles in 2007-2018 years.Table

Figure 2 :
Figure 2: Distribution of independent and cooperative article on the world

Table 1
6 forms with their research productivity attaching by ten countries as United State (USA), United Kingdom (UK), Canada, Germany, China, Australia, France, Spain, Italy, and Netherland.It indicates that Article form has the most publishing output with 19917 articles with the first ranking, following distantly as Editorial Material 1724 articles (2 nd ), Review 1631 articles (3 rd ), Proceedings Paper 572 articles (4 th ), Letter 416 articles (5 th ), and Correction 258 articles (6 th ) with the last ranking.Besides, the Article form is popular research production in total countries and it normally occupies the highest publishing output number in total research types.Particular, USA has 4370 articles and occupies 21.94% of total Article form, following as 2079 articles (China, 10.44%); 1493 articles (UK, 7.5%); 1202 articles (Australia, 10.44%); 1110 articles (Germany, 5.57%); 1089 articles (Canada, 5.47%); 608 articles (France, 3.05%); 589 articles (Spain, 2.96%); 507 articles (Italy, 2.55%); and 441 article belongs to Netherland with 2.21%.Furthermore, research publication of Article form is higher than other forms in big gap.It has 19917 articles in 2007-2018 while other forms only have some hundreds to thousands of research publication.On the table 1 is also seen that USA is a country, which is always has the highest research output about all the Article forms in top ten countries, next is UK (2 nd country) in Editorial Material form (202 articles, 11.72%) and Review form (248 articles, 15.21%).But in the Article form, the second ranking in countries is China with 2079 articles (10.44%).In Editorial Material form and Review form, China is ranked the fifth and Australia is ranked in 3 rd , Germany and Canada are the fourth ranking about research output.Generally, in the article type has seen that Article form has the highest research publication whereas other forms merely have from some articles to hundred articles.The distribution of article types by countries in[2007][2008][2009][2010][2011][2012][2013][2014][2015][2016][2017][2018]

Table 2
Distribution of journal in 2007Distribution of journal in  -2018