It won’t work. Advocates claim that cellulosic ethanol has a positive energy return – that is, the magnitude of energy required for biomass production and conversion is smaller than the magnitude of energy displaced by the ethanol produced. And this claim has been carefully crafted to convey the idea that (a) cellulosic ethanol can replace fossil fuels, and that (b) we should be happy with this new technology, because cellulosic ethanol is an energy-positive fuel and therefore, the more we drive the more we save.

This is clearly not the case. The positive energy return proposition assumes that fossil fuels alone are the limiting factor in the production of an agrofuel, and that all other factors are limitless, and therefore irrelevant. In particular, it is assumed that:
1. The Earth provides us with an infinite and instantaneous supply of pure air, fertile soil, and clean, nutrient-rich water.
2. Nature can purify all the water and air we pollute, and regenerate all the soil we erode or otherwise destroy.
3. Mother Earth can feed 7 to 12 billion people, 1 billion cows and all other non-human consumers of plant and animal matter indefinitely.
4. She can also indefinitely feed 1 billion cars and trucks (620 million produced since 1961).

These assumptions were shown to be false by the early 19th century scientists; therefore, a proposition based on them is also false and must be rejected. Interestingly, many 21st century economists still live on an infinite Earth, truly believing that her resources are limitless.

If the positive energy-return proposition is indefensible, what might replace it? A defensible proposition may read like this:
1. Every large ecosystem on Earth must approach a steady state, characterized by zero net ecosystem productivity (NEP, explained below).
2. When humans are not a natural part of an ecosystem (meaning that they subsist, die, and are recycled in it), large-scale biomass harvesting by humans leads to an eventual breakdown of that ecosystem.
3. Remedial actions (waste cleanup, erosion control, and nutrient applications) become necessary to slow down – but never stop – the ecosystem deterioration.
4. These actions require massive inputs of fossil energy and are utterly unsustainable.

From the energy viewpoint, ecosystems are characterized as follows:
1. The amount of carbon dioxide converted by plant photosynthesis into biomass is called gross primary productivity (GPP).
2. The amount of energy plants and animals eat to live is called respiration.
3. The amount of energy in biomass built in one year by the plants is called net primary productivity (NPP). NPP is equal to GPP minus plant respiration.
4. The amount of energy produced in an ecosystem in one year from animals, plants and decomposers is called net ecosystem productivity (NEP). NEP is equal to NPP minus animal respiration.

It turns out that plants eat roughly half of whatever they sequester and animals eat 95 percent of the rest. On average, therefore, the net productivity of established ecosystems oscillates around zero. Consequently, for agriculture, from which we extract biomass each year, we must put in substantial amounts of fossil energy. (Which we do through large inputs of ammonia fertilizer manufactured via the Haber-Bosch process.)

Why is net ecosystem productivity zero? Why is there no biowaste or surplus production in a large established ecosystem that does not receive subsidies from outside?

The fundamental reason for this law of nature comes from physics. Because of gravity, mass cannot leave the Earth – only some heat can. Therefore, all ecosystems on the planet must recycle all mass efficiently and emit only waste heat. Otherwise, chemical wastes would build in these ecosystems and destroy them. Humans have interrupted most natural cycles, and replaced them with irreversible and perpetually declining linear depletion (mining) processes. For example, fields with pastures and cows naturally recycle 85 percent of what cows eat. Move cows to remote feedlots, and we have a huge fertilizer problem in agriculture and a corresponding problem with toxic manure waste in the feedlots. Agrofuels are products of the incredibly fast and harmful environment-mining processes that are by definition unsustainable.

So how much of the global net primary productivity do we consume? According to NASA, in many parts of Asia (India, China, Indonesia, etc.), most of Europe, the eastern United States, and coastal areas of South Africa, we already use 100 to 200 percent of the local NPP. In big cities this number jumps to 40,000 percent, and on average we command about 60 percent of global NPP.

Europeans are finally realizing this fact. Thus the OECD and some European governments have proposed freezing all agrofuel production. They are also reassessing the best ways to reduce CO2 emissions and uncouple agriculture subsidies from agrofuels. Germany, for example, has introduced the most sophisticated science-based government policy on agrofuels and might freeze their purchase. In contrast, the U.S. remains rooted in the settler mentality of the endless frontier.

Sooner or later, the E.U. and the U.S. will wake up to the grim reality of the agrofuel delusion. Let’s hope it doesn’t take too long.