An Update toward Rational Thinking on the Greenhouse Issue
With the agreed upon trend toward current warming of our earth, there is concern that we should face the problems that may affect all present life forms. The extent to which the warming can be attributed to our lifestyle is not clear, because there have been previous periods of so-called ice ages with intermittent warm periods well before the presence of humans on the earth. Moreover, though carbon dioxide seems to be a factor in greenhouse gas forcing of climate, this specific factor is known to have played a role in periods much earlier than the presence of humans. In a recent issue (1/5/07) of Science, the publication of the American Association for the Advancement of Science, a team of scientists (Montanez et al.) from academia, research institutions, and government published their detailed finding on "CO2-Forced Climate and Vegetation Instability during Late Paleozoic Deglaciation". Results from the multipronged investigation provide evidence for past CO2-forced climate linkage that covers a 40-million year period of the late Paleozoic which was 305 to 265 million years ago. The genus of Homo spans only about a million years, Homo sapiens perhaps 40,000 years, and modern, civilized and fuel-consuming humans less than 10,000 years. Hence, one can easily see that we are a very late comer to the CO2 greenhouse story as one element in the warming that occurs between glacial periods.
None-the-less, it seems likely that we are contributing to the present warming period with our increasing consumption of fossil fuels and resultant CO2 production. One obvious suggestion is to decrease our gluttonous over-consumption of such fuels, which include petroleum products. This has led to a number of suggested alternative sources of energy, among which are ways of replacing all or part of gasoline with other combustible natural materials, e.g. ethanol. This compound results from the fermentation of sugars derived from plants. Two presently used sources are sugar cane, used in Brazil, and corn which provides starch that is converted to sugar, suggested to be a major item for the US. Both hold false promise for realistic, economic benefit. A well-thought-out article written by Dan Chapman for the Sunday, January 14 issue of The Atlanta Journal-Constitution states that "Ethanol fever could produce hangover". As correctly pointed out, the production of ethanol from corn or sugar cane uses more energy than it generates. Worse yet is the tie-up and potential expansion of land that would be devoted to such monocultures. In the December 8, 2006 issue of Science, Tilman et al. from the University of Minnesota write on "Carbon-Negative Biofuels from Low-Input High-Diversity Grassland Biomass". These investigators emphasize that biofuels derived from mixtures of native grassland perennials can provide more usable energy, greater greenhouse gas reductions, and less agricultural pollution per comparable space than corn grain ethanol or soybean biodiesel. Moreover, such native grassland perennials can be produced on agriculturally degraded lands and thus would neither displace food production nor cause loss of biodiversity via habitat destruction.
The above points emphasize that we still have much to learn about all the factors that contribute to the cyclical warm-freeze periods that our planet undergoes; however, the human contribution to this phenomenon, though clearly a part, is not yet quantified. It is certain, though, that our waste cannot be sustained as regards use of present fossil fuels. In seeking alternative fuels, especially for gasoline, we must be careful not to let money-seeking opportunists sell us the wrong substitutes. --- Don McCormick