Energy Articles > Impacts > Climate Change
The Enhanced Greenhouse Effect, Part I
By Robert Farmer
The following has been adapted from the author’s presentation to the Annual Meeting of the Florida Engineering Society, August 1998, Marco Island, Florida.
Easy to overlook in the confusing rhetoric of the climate change debate is the fact that there is no uncertainty about the Enhanced Greenhouse Effect. Why is that significant? We’re all familiar with the concept of cause and effect. The disease and the symptom. The Enhanced Greenhouse Effect (EGE) is a subtle yet pernicious atmospheric disease. Global climate change is its symptom. It is the enhanced greenhouse effect that we need to mitigate.
Fortunately, or unfortunately, depending on how you look at it, we know for certain how dangerous the EGE really is. We’ve known about its effects for about 200 hundred years, but it was the middle of the 19th century when the Irish physcist John Tyndall placed the knowledge on sound scientific footing. He measured the absorption of infra-red radiation by carbon dioxide and water vapor, and confirmed that certain gases trap the sun’s reflected heat.
One hundred years ago the first calculations for the EGE began to emerge with the work of Swedish chemist and Nobel laureate, Svante Arrhenius. He showed that the atmosphere allowed short-wave sunlight to pass freely to the Earth’s surface but trapped the long-wave, infra-red radiation re-radiated by the Earth. His model included what became known as a “feedback loop”. Rising atmospheric temperatures cause increased water evaporation which, in turn, provides additional water vapor for the absorption of heat. A self-perpetuating cycle.
Interestingly, in the 1960s the Venus probe Mariner II measured the surface temperature of Venus at about 660°F-600°F warmer than Earth. More recent Russian probes have found temperatures of 970°F on the surface of the planet! Venus’ atmosphere is almost entirely carbon dioxide-sort of a super greenhouse, if you will.
For 60 years there was general agreement in the scientific community that the oceans, with their large capacity to store carbon, would absorb almost all carbon dioxide emitted into the atmosphere, and little further work was done on the Enhanced Greenhouse Effect.
But in 1957, Roger Revelle and Hans Suess of the Scripps Institute of Oceanography reported that the ocean had not absorbed as much carbon dioxide as everyone had previously assumed.
Next month: David Keeling measures atmospheric carbon dioxide levels and scientists confirm the bad news-rising CO2 levels are caused by deforestation and the burning of fossil fuels. •
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