By Eric Grimsrud
Retired MSU Professor and Climate Change Expert
Citizens of Montana are being misinformed on the single most important detail concerning the effects of our increasing levels of carbon dioxide on the Earth’s temperature.
I am referring to what is called the “sensitivity” of CO2, which is defined to be the temperature increase caused by a doubling of the CO2 concentration in the atmosphere. Direct measurements of temperature and CO2 levels over the past 700,000 years — as revealed by the ice core records of Antarctica and Greenland — show that the total sensitivity of CO2 is about 6.5 degrees Celsius. About half of this has been attributed to “fast” feedback effects (changes in water vapor and clouds) that become apparent in a few decades and the other half is due to subsequent “slow” feedback effects (such changes in the sheet ice of Greenland and Antarctica) that show up over the course of a few centuries. All of this is thoroughly explained in “Target Atmospheric CO2” in The Open Atmospheric Science Journal, 2008, volume 2, pages 217-231.
Magnitude of change
The most recent ploy of the professional deniers of CO2’s effects is to acknowledge that increased CO2 will cause an increase in temperature, but then claim that the magnitude of this effect will be too small to be of importance. An excellent example of this national effort is being provided in Montana by H. Leighton Steward who presents himself as a scientific expert on the subject of climate change. He is the director of EOG, a gas and oil company formerly known as Enron. He is also the spokesperson for a fossil fuel advocacy group called Plants Need CO2, whose advertisements have been shown frequently throughout Montana.
Steward assures us that the Earth’s temperature can increase by no more than 0.2 degrees Celsius — even if we let carbon dioxide levels increase without constraints during the rest of this century and into the next. Thus, he is claiming that the sensitivity of CO2 will always be less than 0.2 degrees C, far less than the measured magnitudes referred to above.
He bases his comforting prediction entirely on century-old, oversimplistic theory that is contradicted by modern physical principles and direct observations. His model is of no relevance to the real world because it accounts only for the absorption of infrared radiation by the greenhouse gases and does not also include the emission of this radiation by these same molecules. While this deficiency in Steward’s model becomes apparent upon inspection of any basic textbook on the subject, it is also revealed in the layperson-friendly article “Understanding Atmospheric Radiation and the Greenhouse Effect — Parts Two and Three” available on the web at www.scienceofdoom.com.
Disconnected from reality
In fact, the emission of infrared radiation in all directions by the greenhouse gases of the atmosphere is just as important as their absorption. That is why Steward’s predictions of CO2’s sensitivity are far too low and entirely disconnected from reality. In addition, the more correct model shows that the temperature effects of increased CO2 levels will continue almost endlessly into future decades and centuries — while Steward tells us that CO2’s effect is already “saturated” and, therefore, future generations need not be concerned about future increases in CO2.
Unfortunately, Steward’s lethal message appears to have been well-received and additionally amplified by powerful fossil fuel interests in Montana. I have tried to create a line of communication with both the Montana Petroleum Association and Steward in an effort to correct this critically important detail of future warming — without success. Therefore, I am sharing my own thoughts here directly with the citizens of Billings. Please beware of so-called “scientific experts” bearing tales of “happy science” that attempt to take CO2 emissions off the hook in our efforts to address climate change. While such presentations might be driven by legitimate and understandable financial concerns, they are also in direct opposition to the laws of Mother Nature and have a very high probability of leading to environmental catastrophes in the coming decades and centuries.
Eric Grimsrud, emeritus chemistry professor at Montana State University in Bozeman, lives near Kalispell. His website is www.ericgrimsrud.com.
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