Regarding Jeff Falen's letter denouncing biodiesel on the basis that atmospheric carbon is atmospheric carbon regardless of its source (HCN, 10/17/05), I must disagree on three counts:
While there is a mostly finite amount of carbon on the earth and in its atmosphere, sizable amounts are stored within the crust. Humans really began distorting the carbon equation in the Industrial Age by using crust-based fuels. So to say that adding carbon from the earth's crust (via petroleum, gas or coal combustion) is equal to adding carbon from plant-based oils seems short-sighted.
Second, it is not sustaining to the present world situation to stop heating homes, or sustaining to economies to stop having cars. So why not start the curve toward a new paradigm by using renewable plant-based oils (biodiesel and ethanol) that can be delivered into existing infrastructures for use in many existing vehicles?
Third, the biodiesel I buy is not virgin vegetable oil but converted fry oil that (in sufficient quantities) is regulated by the EPA as industrial waste. So why deal with it as industrial waste when with minor chemical changes (and useful byproducts) we can burn it in place of petroleum diesel? You make the call.