Global warming has a history that began before industry
John Burke’s “Search results” letter (Saturday Review-Journal) wants factual support that carbon dioxide isn’t the major cause of global warming.
How about this? From roughly A.D. 950-1250 the Earth warmed considerably in what is called the Medieval Warm Period. Then the temperatures dropped significantly during what is called the Little Ice Age, warming back up again by the mid-1800s. During those 900 years of global warming and cooling, there were no smokestacks, no factories, no internal combustion engines, no fossil fuels and no manufactured carbon dioxide. So, Mr. Eco-Warrior, there is your support.
Impartial researchers attribute the changes to variations in solar activity, volcanic activity, the “wobble” of Earth’s axis and changing oceanic circulations. Those, I suggest, are valid counterarguments that should also be prominently displayed on the search engine pages.