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Human impact on climate isn't disputed by scientists

JEFF G. WARDESKA • Feb 28, 2014 at 9:10 AM

Ron McCarley’s recent letter, “Disputing Depelteau,” requires comment. Many of his assertions are incorrect. He chooses to disregard Dr. Audrey M. Depelteau’s overall emphasis on the evidence of global warming; rising global atmospheric temperatures (Google the “Hockey Stick Curve”), rising carbon dioxide levels (Google the “Keeling Curve”), melting glaciers worldwide, and seeks to downplay the fact of scientific consensus. Science is based on evidence, not consensus. There is overwhelming consensus, however, among scientists worldwide regarding the influence of human activities on global climate change. Eighteen major scientific societies in the United States (nasa.gov/scientific-consensus) and more than 200 scientific organizations worldwide (Wikipedia.org, “Scientific Opinion on Climate Change”) are on record stating that the impact of human activities on the climate is undeniable. For example, the National Academy of Sciences in 2005 stated “The scientific understanding of climate change is now sufficiently clear to justify taking steps to reduce the overall amount of greenhouse gases in the atmosphere.” The Wikipedia entry also references eight surveys of scientists (disputing MaCarley’s claim of no such studies) showing an overall 89.8 percent consensus, and states “No scientific body of national or international standing maintains a formal opinion dissenting from any of these points.”As basis for his argument, McCarley cites the Doran/Zimmerman study, which he implies arbitrarily selected 79 responses to show the 97.5 percent consensus. The study received 3,146 responses showing 90 percent consensus among earth scientists. The “selected” 79 were scientists whose primary field of research was climate change (a reasonable subset to study), and these indeed responded at the 97.5 percent level. There really is no debate among scientists.The issue we should be discussing is what kind of world we want to leave for future generations. Are we willing to gamble the futures of our children and grandchildren that the predictions of global warming are wrong?JEFF G. WARDESKAJohnson City