   The Science Behind Climate Change - November 11, 2009 Jeff Schalau, Associate Agent, Agriculture & Natural Resources University of Arizona Cooperative Extension, Yavapai County After hosting two eminent tree ring research scientists for an evening lecture on climate change October 29, I have come to realize that people want to hear more than just the evidence related to climate change. I think people also want to see an evaluation of the scientific evidence which supports and/or refutes climate change. This is especially true when we enter into discussions about anthropogenic (human-caused) climate change. In search of balance, we need to try to evaluate the merit of the science and seek a greater understanding the scientific process. To that end, let’s examine climate change from a scientific perspective. The Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report (2007) states that the warming of the earth’s climate system is unequivocal. This report goes on to state that most of the observed increase in globally averaged temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic greenhouse gas concentrations and predicts that world temperatures could rise by between 1.1 and 6.4 °C (2.0 and 11.5 °F) and sea levels will probably rise by 18 to 59 cm (7.08 to 23.22 in) during the 21st century. I think that a natural human emotion is to hope these predictions do not prove to be true. It causes me great concern too. By the way, the IPCC was established in 1988 by the World Meteorological Organization (WMO) and the United Nations Environment Programme (UNEP), two organizations of the United Nations. The IPCC bases its assessment mainly on peer-reviewed and published scientific literature and their reports are widely cited in almost any debate related to climate change. I have also included a link to the IPCC website below. Over 97% of the climatologists that actively conduct research and publish agreed that human activity is a significant contributing factor in changing mean global temperatures (Doran and Zimmerman, 2009, their journal article is linked below). This is contrasted by only 58% of the general public sharing that assertion. This illustrates the great divide between the climate science community and the general public. Doran and Zimmerman suggest the lack of communication between climate researchers and policy makers as a potential cause for this disparity and surmise that this may have led to a public that continues to mistakenly perceive debate among climate scientists. The debate among climate scientists over anthropogenic causes is very limited because they are largely in agreement. It should also be noted that while respondents’ names were kept private, Doran and Zimmerman included participants with well-documented dissenting opinions on global warming theory. In addressing the issue of peer-reviewed and published scientific literature, the strength of this system is inherent. Scientists subject their research findings to the scrutiny of their peers, which includes disclosing the methods that they used to conduct the research, so their results can be checked through replication by other scientists. The insights and research results of individual scientists, are thus confirmed or rejected in the peer-reviewed literature by the combined efforts of many other scientists. This system seems to be working quite well for all other areas of science, so it should work just as effectively for climate science. As a faculty member of the University of Arizona College of Agriculture and Life Sciences, it is my mission to promote the use of peer-reviewed research and accepted science to help improve the lives of the citizens of Yavapai County. In addressing the divide between climate researchers and the general public, I recommend that we marginalize our emotions and look at what the peer-reviewed science is telling us. Also, beware of blogs, editorials, and other sources of biased information. As a parting thought, when Albert Einstein was informed of the publication of a book entitled 100 Authors Against Einstein, he is said to have remarked, “If I were wrong, then one would have been enough!”. The University of Arizona Cooperative Extension has publications and information on gardening and pest control. If you have other gardening questions, call the Master Gardener line in the Cottonwood office at 646-9113 ext. 14 or E-mail us at cottonwoodmg@yahoo.com and be sure to include your address and phone number. Find past Backyard Gardener columns or submit column ideas at the Backyard Gardener web site: http://cals.arizona.edu/yavapai/anr/hort/byg/. Web Links Link to the Intergovernmental Panel on Climate Change website: www.ipcc.ch Doran, P.T. and M.K. Zimmerman. (2009) Examining the Scientific Consensus on Climate Change. EOS 90:3. 2pp. http://tigger.uic.edu/~pdoran/012009_Doran_final.pdf. |