Addiction to Oil

When George W. Bush, in his 2006 State of the Union address, said "Here we have a serious problem: America is addicted to oil . . .", he was far from the first to make that observation. But the irony of that statement coming from the mouth of a former oil pusher made it memorable. Moreover, it's not just America's problem; it's the world's.

Powering our vehicles with alternative fuels from renewable resources will continue to add carbon dioxide to the atmosphere, but that carbon dioxide will have been previously absorbed from the atmosphere in growing the fuel plants; thus a complete replacement of fossil fuels with fuels from so-called biomass will not reduce the carbon dioxide contributing to global warming, but at least it will not increase it further. Most current methods of producing fuel from biomass use energy generated from fossil fuels, so that there still is a net increase of atmospheric carbon dioxide, though a smaller increase than would occur without renewable fuels. Farming the vegetable matter for these fuels on any large scale will require a major expansion of agricultural lands and will have widespread ecological repercussions.

Buried Sunshine

Burning buried sunshine (fossil fuels) turns out to be a spectacularly inefficient way of using solar energy.

In his paper "Burning buried sunshine: human consumption of ancient solar energy" (Climatic Change, 61, pp 31–44, 2003) Jeffrey Dukes provides the calculations, which have a considerable range of uncertainty around best estimates, but are alarming even with that uncertainty. Dukes's results dramatically emphasize our profligacy. He calculated recovery factors: how much of the carbon originally in the ancient organic matter remains after conversion to coal, oil, and gas and the extraction of these fuels from the ground. For coal he arrived at a best estimate of 9%; for oil, 0.009%; for gas, 0.008%. By combining these recovery factors with statistics for fuel consumption, Dukes estimated that the original organic matter from which the fossil fuel burned in 1997 was derived held about 44 trillion tons of carbon, over 400 times the amount of carbon fixed annually by biological processes, about 105 billion tons. That is, each year we burn up what took over 400 years of plant growth to lay down. Almost all of this is from oil and gas even though 38% of the fossil carbon consumed in 1997 was in the form of coal, because of the thousand-fold greater recovery factor for coal compared to oil and gas; coal accounts for a mere 3 months of the 400 years. Another way to view the results, taking into account the efficiency of photosynthesis, is that producing those 44 trillion tons of carbon requires 36 years worth of the entire solar energy striking the earth.

Think about this the next time you fill up at the gas station: each gallon of gasoline is distilled from about 100 tons of ancient plant matter. (For the pedantic, those are US tons here and metric tons in the previous paragraph, but given the uncertainties in the calculations, it's not really worth making the distinction.)

Dukes went on to estimate that to replace energy from fossil fuels with energy from modern biomass would increase human demands on terrestrial photosynthetic resources by 50%, which would have significant accompanying environmental and ecological consequences.

Links to discussion of the paper can be found at one of Jeff Dukes's pages, and a link to the paper itself is at the bottom of that page.