Proceedings of theInternational Conference on Power Engineering-09(ICOPE-09) November 16-20, 2009, Kobe, Japan

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REPORT FROM E-MAIL DISCUSSION
ON “GLOBAL WARMING: WHAT IS THE SCIENTIFIC TRUTH?”
Hideo YOSHIDA**Department of Aeronautics and Astronautics, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
ABSTRACT
Global warming is currently a key topic in international politics; therefore, the impact ofmeasures taken to counteract it is enormous. However, it should be noted that considerable controversy
surrounds the scientific truth on global warming. Therefore, clarifying the scientific truth is both urgent andcrucial. To this end, the author, as vice chairman of the editorial committee of the Japan Society of Energy andResources, coordinated an e-mail discussion among five prominent Japanese scientists. The full text in Japanese,
including data forming the basis of the discussion, is available for download from the homepage of the Japan
Society of Energy and Resources (http://www.jser.gr.jp/). To the author’s knowledge, the discussion, supporting
papers, and associated data represent the first trial of its kind. On the occasion of ICOPE-09, the coordinatorsummarizes the outline of the e-mail discussion and illustrates state-of-the-art research on global warming.
Keywords: Global warming, Scientific truth, IPCC, CO2, E-mail discussion
1. INTRODUCTION
This paper is a brief introduction to an e-maildiscussion originally published in the January and March2009 issues of the Journal of the Japan Society of Energy
and Resources (JJSER) in Japanese [1] [2]. Since the author
served as coordinator of the discussion, this chapter begins
with the English translations of “the cover page of thearticle shown in Fig. 1” and “Preface,” both of which wereprepared by the coordinator.
“Global Warming: What is the Scientific Truth?”
The earth’s climate is a very complex system resulting
from interactions of the solar system, atmosphere, ocean,and continents. The phenomena of the climate consist ofnumerous physical and chemical processes with various
space and time scales, and their effects on the climate are
not always linear but frequently nonlinear. Therefore,scientific clarification of the climate is extremely difficult
despite a large number of scientists having devoted
considerable time to this task. Consequently, the truth andfacts behind the causes of global warming remain
controversial. In this issue, five prominent scientists withdiffering standpoints have conducted a valuable e-maildiscussion.
Prof. Syun-Ichi. Akasofu, Alaska University, USA (Top in
Fig. 1)
Dr. Seita Emori, National Institute for Environmental
Studies, Japan (Lower left in Fig. 1)
Prof. Kiminori Itoh, Yokohama National University, Japan(Upper left in Fig. 1)
Dr. Kanya Kusano, Japan Agency for Marine-Earth Scienceand Technology, Japan (now Prof. of Nagoya University)(Lower right in Fig. 1)
Prof. Shigenori Maruyama, Tokyo Institute of Technology,
Japan (Upper right in Fig. 1)

Fig. 1 The cover page of the article published in
the Journal of the Japan Society of Energy and Resources,
January 2009

Copyright © 2009 by the Japan Society of Mechanical Engineers

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Preface
On the next day of June 23, 1988, The New York Times
reported the following:
Global Warming Has Begun, Expert Tells Senate
Dr. James E. Hansen of the National Aeronautics
and Space Administration told a Congressional
committee that it was 99 percent certain that thewarming trend was not a natural variation but
was caused by a buildup of carbon dioxide andother artificial gases in the atmosphere.
Nearly 20 years after Dr. Hansen’s statement, the 2007
Nobel peace prize was awarded jointly to Mr. Al Gore andthe Intergovernmental Panel on Climate Change (IPCC).
Global warming therefore came considered an important
topic, and concerted global efforts have been made to
reduce CO2 emission, which is regarded as the principal
cause of global warming. However, while most governments,organizations, mass media report, and people in generalbelieve that global warming results from increased
concentrations of CO2 in the atmosphere, considerable
controversy exists among scientists in the US, Europe, andJapan. Scientists opposed to the conclusions of the IPCC
are often referred to as skeptics or naysayers.
As the mitigation of global warming was the main
topic at the G8 Hokkaido Toyako Summit 2008, its socialand economic impacts are enormous, rightly or wrongly. Itis, however, dangerous to take hasty and strong action to
reduce CO2 emissions purely on the basis of precautionary
measures, without having firm scientific consensus on thetrue causes. The following opinion is common: Irrespectiveof the ultimate cause of global warming, all movements to
reduce CO2 emissions are welcome in terms of mankind
becoming aware of the earth’s limitations and therefore
seeking to save energy and resources. However, we should
not forget essential scientific discussions.
As an alternative to the conventional New Year talk in
the JJSER, I proposed an e-mail discussion on theseimportant topics. Although similar trials have been
conducted in some TV programs, their limitations were
obvious; talks at cross purposes and the extinction of the
discussion shortly after the programs aired. In this issue,
five scientists conducted preliminary discussions on theframework of the main discussion, exchanging indepth andwell-researched e-mails with data to support theirconclusions. Since their e-mails are recorded in the JJSER,
and their supporting data was uploaded to the homepage of
JSER (http://www.jser.gr.jp/), readers can consider theiropinions and determine which opinions are morereasonable. In the future, this issue will serve as a precious
archive on global warming in the early 21st century.
It should be noted that the scope of the discussion islimited to purely scientific topics on the phenomena relating
to the temperature characteristics of the earth’s surface,although there is wide political and economic scope to theglobal warming argument.
At this juncture, I would like to add a few words

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repeatedly considered during the discussion. The words“science” and “conscience” are almost identical; bothstem from “scio” in Latin, meaning “to know.” Hence,
making efforts to find the truth through sincere discussion isconsidered to be “science” and/or “conscience.” I express
my gratitude to the five splendid scientists who conducted
the discussion “in a spirit of scientific detachment.”(Bertrand Russell; Why man should keep away from themoon, The Times, July 15, 1969)
Listening to “Smile” (Charlie Chaplin; Modern Times,
1936), a famous song in the 20th century, and thinking of
the day when the present discussion will be a precious
archive of the 21st century.
December 16, 2008
Coordinator
Vice chairman of the editorial committee of JSER
Hideo Yoshida, Professor of Kyoto University

2. PREPARATION OF E-MAIL DISCUSSION
The present discussion was conducted by e-mailamong the five scientists and the coordinator. During theinitial three months (July–September, 2008), we prepared aframework for the discussion. First, to mutually understandviewpoints, a preliminary questionnaire based on so-called“SPM by WG1 in the fourth Assessment Report of IPCC”
and shown in Table 1, was issued. Since this is just a simple
triple-choice questionnaire, it should be noted that Table 1
merely shows unspecific images of the five scientists. It isclear that only Dr. Emori supports the IPCC conclusions—to which he had made an active contribution. It is worth
noting that various opinions exist, even among the skeptics
and naysayers.
In the light of the results shown in Table 1, we
anticipated the ensuing discussions and decided toconcentrate on the two topics:
Part 1 Causes of Temperature Rise in the Late 20th
Century,
Part 2 Future Predictions.
We later added a third topic
Part 3 Others,
when we extended the discussion to the March 2009 issue.
The list of formal e-mails is shown in Table 2. However, by
the end of the discussion, we had actually exchanged morethan one thousand e-mails.
In principle, once the e-mail discussion started in
October 2008, there was a simultaneous exchange ofe-mails. To clearly demonstrate the time sequence of thesuccessive e-mails, the date of each e-mail was recorded;
the one exception being the real-time e-mail discussion in
4.4. This is a slightly edited form of the discussion and isbased on the numerous e-mails exchanged between Prof.
Maruyama and Dr. Emori on February 19 and 20, 2009.

Table 1 Results of Preliminary Questionnaire to Understand Five Scientists’ Standpoints(○: agree, ∆: partly agree, ×: do not agree)
The Fourth Assessment Report of the IPCC
AkaA report of Working Group I of the IPCC, Summary for Policymakers
Emori
Itoh
sofu
http://www.ipcc.ch/pdf/assessment-report/ar4/wg1/ar4-wg1-spm.pdf
Global atmospheric concentrations of carbon dioxide, methane and nitrous oxide
have increased markedly as a result of human activities since 1750 and now far
exceed pre-industrial values determined from ice cores spanning many thousands○○○of years. The global increases in carbon dioxide concentration are due primarily
to fossil fuel use and land use change, while those of methane and nitrous oxide
are primarily due to agriculture.
Warming of the climate system is unequivocal, as is now evident fromobservations of increases in global average air and ocean temperatures,∆○○widespread melting of snow and ice, and rising global average sea level.
Palaeoclimatic information supports the interpretation that the warmth of the last∆×○
half century is unusual in at least the previous 1,300 years.
Most of the observed increase in global average temperatures since the mid-20th
century is very likely due to the observed increase in anthropogenic greenhousegas concentrations. Discernible human influences now extend to other aspects of×○×climate, including ocean warming, continental-average temperatures, temperature
extremes and wind patterns.
Continued greenhouse gas emissions at or above current rates would cause
further warming and induce many changes in the global climate system during∆×○
the 21st century that would very likely be larger than those observed during the20th century.

3. BRIEF REVIEW OF E-MAIL DISCUSSION
Since the five scientists have different backgrounds
and viewpoints, the coordinator initially expected thediscussion to be conducted among all five scientists, invarious combinations. However, most of the discussion
involved Dr. Emori of the IPCC and the other four scientists.
Consequently, Dr. Emori frequently prepared replies to theother four scientists; if necessary, he asked colleagues inJapan and/or abroad to collaborate, their names are listed in
the acknowledgements in his papers. The entire discussion
consists of 32 mails (sections).
It is extremely difficult for the coordinator tosummarize the e-mail discussions covering numerous topics
and offering profound insights into the subject.
Perhaps, the only common agreement among the fivescientists is that the temperature rise in the late 20th century
is indisputable. Prof. Akasofu, however, stressed that it ismainly due to the superposition of two natural oscillations,and that global warming has recently stopped. AlthoughProf. Itoh partly agreed with the anthropogenic effect, hesimultaneously pointed out the importance of naturalvariation and the uncertainty of temperature measurement.
Prof. Maruyama’s viewpoint is mainly based on along-range time scale, and he has focused on the sun’s
activity. Dr. Emori response was that although someuncertainty inevitably exists, the conclusion drawn by IPCC
is reasonable in terms of the available data.
Concerning the global circulation model (GCM), theprediction from which forms the basis of the IPCC’s
conclusion, all five scientists, including Dr. Emori, referred
to its incomplete nature. In particular, Dr. Kusano and Dr.
Emori exchanged many key opinions on the GCM.
Although Dr. Kusano considered that the global warming
predicted by the GCM models is merely a hypothesis at

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KusanoMaruyama

∆

×

○

○

×

×

×

×

×

×

present, both he and Dr. Emori displayed a mutual
understanding.
Among the five scientists, Prof. Itoh was most active
in expressing his opinions on a wide range of global
warming topics, and continuously led the entire discussion
through to its final stage. Part 3 of the paper, published in
the March issue, covered various topics that had not been
properly categorized into either Part 1 or Part 2; including
7.1, in which Prof. Itoh’s question was directed to Prof.
Maruyama, unlike the other discussions entailing Dr. Emoriand one of the other four scientists.
The differences in opinion between Dr. Emori and theother four scientists were not mitigated after the discussion.
However, without doubt, the present discussion is of thehighest level and is the most focused of all previous
discussions.
4. IMPACT OF PUBLICATION ON THE INTERNET
Just before the publication of the January issue, thefive scientists and the coordinator agreed to simultaneously
publish the discussion on the homepage of JSER
(http://www.jser.gr.jp/). Since the PDF files of the article
are freely accessible, many people in Japan and throughout
the world can access the site.
If you search for the present discussion on the internet,
you will find countless sites referring to it; the coordinatorintroduces some of these sites below.
4.1 In Japan
Japan has three main newspapers—Yomiuri, Asahi,
and Mainichi. All of these newspapers, as well as the
Sankei Shimbun and the Environmental News, reported on
the discussion:

Table 2

Contents of E-mail Discussion

Part 3
OthersPart 2Future Predictions

Part 1
Causes of Temperature Rise
In the Late 20th Century

1. Introductory Discussion
1.1 Akasofu: Global warming has stopped

1.2 Itoh: Temperature increase = natural variations +anthropogenic factors + observational errors
1.3 Emori: Full of misunderstandings, lack of consistency and quantitativity
1.4 Akasofu: Two natural oscillations have caused the present global warming
1.5 Emori: IPCC does not ignore natural variabilities, nor does it guess wrong
2. Uncertainty in Temperature Measurement
3. Climate Sensitivity
2.1 Itoh: IPCC concludes too quickly that “rough-and- 3.1 Itoh: Observation-based estimations appear to show
ready” is dangerous
small climate sensitivity
2.2 Emori: The theories that suggest uncertainty also
3.2 Emori: Evidence is weak for a small climate
require scrutiny
sensitivity
4. Real-time E-mail Discussion Stemming from an Evaluation of Solar Activity
4.1 Emori: Doubt raised on sunspot plot
4.2 Maruyama: Reply to Dr. Emori, role of paleoclimatology, and direction of future study
4.3 Emori: Future projections never depend on paleo-data
4.4 Maruyama and Emori: We had a real-time e-mail discussion
5. State-of-the-art Global Circulation Model, Potential of GCM
5.1 Kusano: Reliability of numerical simulations for future predictions
5.2 Emori: Underestimated reliability of models and overestimated unknown factors
5.3 Kusano: Anthropogenic global warming is still a hypothesis, and we have to explore the various possibilities
5.4 Emori: Theories like cosmic rays never seem to bring “verification”
5.5 Kusano: For our mutual understanding
5.6 Emori: Distinction is needed between qualitative and quantitative validity
5.7 Kusano: How important is it to discuss the quantitative accuracy and uncertainty?
5.8 Emori: Mutual understanding may be reached
5.9 Itoh: On predictive models
5.10 Emori: IPCC never excludes simple methods
5.11 Itoh: On predictions and models
5.12 Emori: On projections and models
6. Factors Governing Local Climate in the Future
6.1 Itoh: CO2 contributes little to regional/local climate changes; still uncertain on other large contributions
6.2 Emori: Factors other than GHGs are surely important for near term and regional/local scales
7. Others
7.1 Itoh: What serves as essential criticism for IPCC?
7.2 Itoh: “Science” in the IPCC reports should be inspected; the case of hurricanes as an example
7.3 Itoh: Relationship between temperature and CO2 concentration
7.4 Emori: “Facts” versus “views”
7.5 Itoh: It may be not detrimental if a mutual understanding cannot be reached- January 12, 2009: The Mainichi Newspapers
http://mainichi.jp/life/ecology/archive/news/2009/01/2
0090112ddm002040147000c.html- January 21, 2009: The Environmental News
http://www.kankyo-news.co.jp/ps/qn/guest/news/show
body.cgi?CCODE=68&NCODE=155- March 2, 2009: The Yomiuri Shimbun
http://www.yomiuri.co.jp/eco/ondan/on090302_01.htm- June 26, 2009: The Asahi Shimbun
https://aspara.asahi.com/blog/science/entry/dypLEK02
2P- August 2, 2009: The Sankei Shimbun
http://sankei.jp.msn.com/science/science/090802/scn0
908021801001-n1.htm

examination:- April, 2009: On global environmental problem
http://www.yomiuri.co.jp/education/kouza/kokugo/090
4/k0904_1.htm
4.2 In the WorldThe Register reported on the discussion, providing an
English translation of some of the papers by Prof. Akasofu
and Dr. Kusano on the following site:- February 25, 2009: Japan's boffins: Global warming isn't
man-made, Climate science is 'ancient astrology',
claims report
http://www.theregister.co.uk/2009/02/25/jstor_climate_report_translation/
This article served as a trigger for international interest in
the discussion. For instance, soon after the publication of
the Register’s article, articles appeared on many sites:- February 25, 2009: Japanese Commission Challenges UN:
Global Warming Not Man-madeOne of the sites, on which we had not expected thediscussion to be covered and were therefore very pleased tolearn of, highlights an example of the problems with theJapanese language being used for a university entrance

2-320physics of global warming. However, generally speaking,since climate change is a complex subject, we have atendency to rely on key information sources in the world.
Although, to some extent, we cannot help being passive
about global warming, we do have a responsibility asengineers and/or scientists to actively consider it. Also, we
are all aware that mechanical engineers usually have wellbalanced views on various complex systems.
In light of the above-mentioned situation, the author
hopes the present e-mail discussion provides valuable
information about this state-of-the-art study on global
warming. The present discussion may not provide a firm
conclusion, but it does make tentative steps toward
discovering the truth about global warming.

http://www.newsbusters.org/blogs/noel-sheppard/2009/02/25/japanese-commission-challenges-un-global-war
ming-not-man-made .
Regrettably, however, not all sites provided correctcomments when referring to the discussion. Therefore, on
the Australian News
- March 14, 2009: Japanese scientists cool on theories
http://www.theaustralian.news.com.au/story/0,25197,2
5182520-2703,00.html
the coordinator quotes the following sentences by Peter
Alford, Tokyo correspondent:
However, the paper's co-ordinator said the JSER's
position on anthropogenic global warming was
neutral. “This paper represents the views of theindividuals and not of the society,” said Hideo
Yoshida, of Kyoto University. “The purpose is tostimulate debate among scholars and readers, andlet them form their own judgment.”

REFERENCES
1.

CONCLUDING REMARKS
A majority of the attendees at ICOPE-09, including theauthor, are mechanical engineers specializing in thermal
and/or fluid engineering related to power and energy.
Therefore, we all have fundamental knowledge of the

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2.

Akasofu, S., Itoh, K., Emori, S., Kusano, K. andMaruyama, S., Global Warming: What Is the Scientific
Truth?, Journal of the Japan Society of Energy andResources, 30 (1) (2009), pp.3-22.
Akasofu, S., Itoh, K., Emori, S., Kusano, K. andMaruyama, S., Global Warming: What Is the Scientific
Truth?, Journal of the Japan Society of Energy andResources, 30 (2) (2009), pp. 1-19.