I agree with the AP article ("Tempers flare up over climate change as temperature rises," Aug. 16) that these days when it comes to science, “nothing beats climate change for divisiveness.” I also agree that “climate change is more about tribalism, or who we identify with politically and socially . … Liberals (climate activists/alarmists) believe in global warming, conservatives (climate skeptics) typically don’t.” But my agreement with Mr. Borenstein stops here. Mr. Borenstein shows his true colors when he says: “Overwhelmingly, scientists who study the issue (global warming) say it is man-made and a real problem.” The real overwhelming fact is that more than 31,000 American scientists (including me) believe that global warming is not a problem. Yes, man-made fossil fuel combustion is adding Carbon Dioxide (CO2) to our atmosphere. And yes, CO2 is adding to the warming of our lower atmosphere via the Greenhouse Effect. But cooling feedback mechanisms generally offset any greenhouse warming. So, any warming we do experience is slight, and then only in a benign and helpful manner. Here’s one reason why — photosynthesis — the chemical reaction of CO2 + H2O (water) + plant life + sunlight, to yield glucose (sugar) + O2 (oxygen). So, as we burn natural gas, oil and coal in power plants and cars, the CO2 enters the air as a combustion by-product. It’s then taken in by plant life and converted to oxygen in the air we breathe and glucose in the food we eat. Best of all, our crop yields are growing and worldwide hunger is decreasing. CO2 is “overwhelmingly” a good gas, not a pollutant. Next, I must also respond to Mr. Borenstein’s hypothesis that basic physics, chemistry, and computer models prove global warming is a coming catastrophe. Our climate is not simple physics and chemistry, rather a highly complex combination/interaction/superposition of solar physics, orbital mechanics, chemistry, meteorology, geology and oceanography that, at best, we still only partially understand. When I compare the “computer model” results referred to by Mr. Borenstein with actual global surface temperature (thermometer) measurements over the period 1880 through the present, the model and measurements are strikingly different. The computer model generally follows measurement (although not well) until about 1998. From that point to today, and on out to their forecast endpoint in 2020, the model predicts a “catastrophic warming” increase. But the reality is that average global temperature anomaly measurements are flat/constant/unchanged from 1998 until today. The model predicts today’s temperature anomaly should be 60 percent higher than was actually measured by thermometers today. If the model were correct, that would be worrisome. But it is not correct and the reason is that the scientific community doesn’t understand the physics well enough yet to predict climate reliably. Worse still, some model developers ignore known cause and effect relationships. One glaring example is the myth that CO2 levels drive temperature. The truth is that temperature drives CO2 levels.William Pekny lives in Midway, Utah. He is a recently retired atmospheric physicist, having worked 48 years in a variety of applied engineering and scientific assignments with the U. S. armed forces and the aerospace industry.