No Observational Evidence That There is Something Unusual, Unnatural or Unprecedented about Earth’s Current Warmth

by Craig D Idso, Ph.D.
The Center for the Study of Carbon Dioxide and Global Change (hereafter, Center) was founded as a non-profit organization in 1998 to provide regular reviews and commentary on new developments in the world-wide scientific quest to determine the climatic and biological consequences of the ongoing rise in the air’s CO2 content. It achieves this objective primarily through the weekly online publication of ‘CO2 Science,’ which is freely available on the Internet at, and contains reviews of recently published peer-reviewed scientific journal articles, original research, and other educational materials germane to the debate over carbon dioxide and global change.
The Center’s main focus is to separate reality from rhetoric in the emotionally-charged debate that swirls around the subject of carbon dioxide and global change and to avoid the stigma of biased advocacy by utilizing sound science. It has a stated commitment to empirical evidence and its position on global warming may be summarized as follows. There is little doubt the carbon dioxide concentration of the atmosphere has risen significantly over the past 100 to 150 years from humanity’s use of fossil fuels and that the Earth has warmed slightly over the same period; but there is no compelling reason to believe that the rise in temperature was caused primarily by the rise in carbon dioxide. Moreover, real world data provide no compelling evidence to suggest that the ongoing rise in the carbon dioxide concentration of the atmosphere will lead to significant global warming or changes in Earth’s climate.
In the 12-year period since its creation in 1998, the Center has published over 3500 timely and objective reviews of scientific research reports on both the biological and climatological effects of atmospheric CO2 enrichment. Accompanying each review is the full peer-reviewed scientific journal reference from which the review was derived, so that patrons may independently obtain the original journal articles and verify the information for themselves.
After a review article is written, it is archived into one or more topical categories inside a massive Subject Index that presently includes nearly 800 topics and subtopics relative to carbon dioxide and global change. The material listed under each subject heading is then periodically reviewed to produce relevant Subject Index Summaries, which are continually updated as newer material is added. Website visitors may use a keyword search engine for ease of locating reviewed articles or summaries; and they may also subscribe to an Internet RSS feed or an email listserver that will notify them of newly posted material.
The Center also provides users with access to various temperature and precipitation databases from which they may calculate and plot trends for the entire globe or for selected regions of the globe. Output includes a graphical representation of temperature or precipitation anomalies over a user-selected time interval, as well as access to these data in tabular form. A linear regression line of the temperature or precipitation trend over time is also displayed along with its associated statistics, which can further be analyzed for significance at the 95% and 99% levels. At present, there are 4 global data sets and 1221 individual station locations in the conterminous United States for which patrons may calculate and plot the climatological data.
Two other important services the Center provides are found in its Plant Growth Database and Medieval Warm Period Project. The Plant Growth database is an ongoing effort to maintain an ever-expanding archive of the results of peer-reviewed scientific studies that report the growth responses of plants to atmospheric CO2 enrichment. Results are updated weekly and posted according to two types of growth response (Dry Weight and Photosynthesis). The data are listed alphabetically according to plant names (both scientific and common) in individual tables and each table begins with an abbreviated reference followed by a brief description of the experimental growing conditions and the percent increase in plant growth due to a 300, 600 or 900 ppm increase in the air’s CO2 concentration. Full reference citations for each experiment are also available in linked files. To date, the Center has archived the results of several thousand CO2-enrichment studies on its website, making this the largest database of this kind in the world.
The Medieval Warm Period Project is an ongoing effort to document the magnitude and spatial and temporal extent of a significant period of warmth that occurred approximately one thousand years ago, when the atmosphere’s CO2 concentration was approximately 30% lower than it is currently. The purpose of this exercise is to show that Earth’s near-surface air temperature was equally as warm as, or even warmer than, it is today during a period of lower CO2 concentration. Thereby, the Center reasons that today’s temperatures are not unnatural and need not be due to the historical rise in the air’s CO2 content, in contrast to the climate-alarmist claim that temperatures during the past two decades were unprecedented over the past two millennia or more. Updates of new scientific studies documenting the climate of the Medieval Warm Period are provided weekly, and users may graphically view individual study locations and attributes on an interactive spatial map.
Students and educational visitors to the Center’s websites may also benefit from the material found in its Global Change Laboratory, where instructions are given on how to conduct simple experiments that illustrate the effects of atmospheric CO2 enrichment and depletion on vegetative growth and development. Utilizing the "Poor Man’s Biosphere" experimental technique pioneered by Center President Dr. Sherwood Idso, plants are grown inside sealed aquariums or other containers maintained at different CO2 concentrations from which students can watch and plot growth progression data over time. Several experiments have been developed to date; and they can be performed by nearly anyone anywhere in the world at very little expense.
The Center is also active in the use of modern media in getting its message out, producing short (1-4 minute) YouTube videos on various topics that can be viewed for free on its website ( In its CO2-Truth Alert video series, the Center highlights the findings of recently released important research papers. In its The Scientists Speak video series, the Center presents excerpts from interviews with various scientists who speak about important aspects of the global warming debate. In addition, the Center has produced three documentary DVDs, Carbon Dioxide and the Climate Crisis: Reality or Illusion?, Carbon Dioxide and the Climate Crisis: Avoiding Plant and Animal Extinctions and Carbon Dioxide and the Climate Crisis: Doing the Right Thing, and it has plans for additional documentaries to be released in the future.
Lastly, the Center and its personnel published three timely and important books in 2009: CO2, Global Warming and Species Extinctions, CO2, Global Warming and Coral Reefs and Climate Change Reconsidered: The 2009 Report of the Nongovernmental International Panel on Climate Change. Each of the books made a significant impact in the global warming debate and none of these books would have been possible without the sustained research and reporting efforts of our Center.
In summation, we view the efforts of our organization as critical in providing an ongoing science-based effort to address and refute the falsehoods that permeate the debate over global warming and the attempt to regulate CO2 as a pollutant. Having thoroughly studied and published numerous scientific journal articles and books on the subject over many decades, we know there is ample peer-reviewed science that shows there is no observational evidence that provides any compelling support for the contention that there is something unusual, unnatural or unprecedented about Earth’s current warmth. Neither are there any real-world data that confirm that floods, droughts or hurricanes are becoming either more frequent or more severe. Nor is there any indication that the total mass of Earth’s polar ice sheets is on the verge of declining any faster than the proverbial snail’s pace at which it has done so in the recent past. Nor is there any reason to believe that sea levels are about to rise precipitously and inundate the world’s coastal lowlands.
The only way to truly counter political efforts to regulate CO2 emissions is by debating the issue on the merits of the pertinent science. Climate alarmists have long utilized the "science" in the Intergovernmental Panel on Climate Change (IPCC) reports as a basis for taking the position that rising atmospheric CO2 concentrations are harming the biosphere and must therefore be regulated. With our ongoing weekly review and publication of important scientific papers, however, they are being forced to confront hard scientific realities that do not support, or that fully contradict, the tenets of their alarmist faith. As efforts to classify CO2 as a pollutant and regulate its emission to the atmosphere continue, the single most important effort that can be undertaken to counter these challenges is to develop a sustained, organized effort to monitor and report the results of new scientific studies that demonstrate that far from being a pollutant, rising carbon dioxide concentrations are a boon to the biosphere. The IPCC and other alarmist organizations are quick to tout all studies that present a pessimistic view of the future to help their regulatory cause. For 12 years now, our organization has provided an important counterbalance and we hope to continue to do so in the future with your support.
Craig D. Idso, Ph.D.
Chairman, Center for the Study of Carbon Dioxide and Global Change
Key Center Staff
CRAIG D. IDSO is the founder and former President of the Center for the Study of Carbon Dioxide and Global Change and currently serves as Chairman of the Center’s board of directors. Dr. Idso received his B.S. in Geography from Arizona State University, his M.S. in Agronomy from the University of Nebraska – Lincoln, and his Ph.D. in Geography from Arizona State University, where he studied as one of a small group of University Graduate Scholars.
Dr. Idso has been involved in the global warming debate for many years and has published scientific articles on issues related to data quality, the growing season, the seasonal cycle of atmospheric CO2, world food supplies, coral reefs, and urban CO2 concentrations, the latter of which he investigated via a National Science Foundation grant as a faculty researcher in the Office of Climatology at Arizona State University. Since 1998, he has been the editor and a chief contributor to the online magazine CO2 Science (, and he also presently serves as the co-Editor for the Assessment Reports of the Nongovernmental International Panel on Climate Change (NIPCC), an international panel of nongovernment scientists and scholars who have come together to understand the causes and consequences of climate change (
Dr. Idso is the author of three books, CO2, Global Warming and Species Extinctions, CO2, Global Warming and Coral Reefs and Climate Change Reconsidered: The 2009 Report of the Nongovernmental International Panel on Climate Change and has produced three video documentaries, Carbon Dioxide and the Climate Crisis: Reality or Illusion?, Carbon Dioxide and the Climate Crisis: Avoiding Plant and Animal Extinctions, and Carbon Dioxide and the Climate Crisis: Doing the Right Thing. He has also lectured in Meteorology at Arizona State University and in Physical Geography at Mesa and Chandler-Gilbert Community Colleges.
Dr. Idso is a former Director of Environmental Science at Peabody Energy in St. Louis, Missouri, and is a member of the American Association for the Advancement of Science, American Geophysical Union, American Meteorological Society, Arizona-Nevada Academy of Sciences, Association of American Geographers, Ecological Society of America, Geological Society of America, and The Honor Society of Phi Kappa Phi.
SHERWOOD B. IDSO assumed the Presidency of the Center for the Study of Carbon Dioxide and Global Change on 4 October 2001. Prior to that time he was a Research Physicist with the U.S. Department of Agriculture’s Agricultural Research Service at the U.S. Water Conservation Laboratory in Phoenix, Arizona, where he worked since June of 1967. He was also closely associated with Arizona State University over most of this period, serving as an Adjunct Professor in the Departments of Geology, Geography, and Botany and Microbiology. His Bachelor of Physics, Master of Science, and Doctor of Philosophy degrees are all from the University of Minnesota.
Dr. Idso is the author or co-author of over 500 scientific publications including the books Carbon Dioxide: Friend or Foe? (1982) and Carbon Dioxide and Global Change: Earth in Transition (1989). He served on the editorial board of the international journal Agricultural and Forest Meteorology from 1973 to 1993 and since 1993 has served on the editorial board of Environmental and Experimental Botany. Over the course of his career, he has been an invited reviewer of manuscripts for 56 different scientific journals and 17 different funding agencies, representing an unusually large array of disciplines.
As a result of his early work in the field of remote sensing, Dr. Idso was honored with an Arthur S. Flemming Award, given in recognition of "his innovative research into fundamental aspects of agricultural-climatological interrelationships affecting food production and the identification of achievable research goals whose attainment could significantly aid in assessment and improvement of world food supplies." This citation continues to express the spirit that animates his current research into the biospheric consequences of the ongoing rise in the air’s CO2 content.