There’s a concept in Jewish tradition called mitzva ha’ba b’aveirah, a mitzvah that gets done as the outcome of a sin is rendered invalid. For instance, one may not blow a stolen shofar on Rosh Hashanah, eat stolen matzah on Passover, or light a stolen menorah on Chanukah. The fact that the mitzvah came out of a sin renders it unacceptable to G-d.

While we already know about the impact biofuels are having on food prices, an article in today’s New York Times makes me wonder if the entire positive impact biofuels will have in the near future is rendered a mitzva ha’ba b’aveirah.

The Times’ Brenda Goodman relates an often-untold story of biofuels — that of pollution, of Alabama’s Black Warrior River being gummed up with grease similar to “Italian salad dressing”, of tankers dumping mysterious “milky white goop” into Missouri’s Belle Fountain Ditch, of Cargill’s Iowa Falls plant killing “hundreds of fish” by improperly disposing of 135,000 gallons of biofuel waste. (582 fish died, and Cargill would pay some $100,000.) Growing American use of ethanol is projected to raise nitrogen levels in the Gulf of Mexico to the point that the “dead zone”, uninhabitable by fish and most crustaceans, is projected to expand past its already horrible 7,700 square miles, and nitrogen levels have to shrink by up to “55 percent” just to begin shrinking it.

Most biofuel disasters are “vegetable oil and glycerin spills”, which, due to their status as being nontoxic for humans, still allow for the claim that “biodiesel is nontoxic, biodegradable and suitable for sensitive environments”.

If we will contend that there is such a commandment in the Torah as bal tashchit (lit.: “you shall not destroy”) which provides Jews the ethical imperative to work toward sustainability, then biofuels’ carbon-neutral or carbon-negative imprints should provide little consolation in the face of polluted rivers and “dead zones”. And, as Britain’s Times Online notes, the space required for planting of biofuel crops on limited agricultural land means less room for food which raises prices of cereals, and this means, to meet the increasing biofuel and food demands:

The alternative is to use uncultivated land. But this could destroy habitats. Particularly if tropical forests or peatbogs are cleared to plant crops, that will release more greenhouses gases than it saves.

There are already very real concerns about the loss of rainforests in Southeast Asia, home to orangutans, which are being cleared to make way for palm oil plantations. The rainforests of Southeast Asia and Brazil are important carbon sinks at the forefront of the war on global warming. The apparent eagerness of these countries to clear their forests is why biofuels have been dubbed “deforestation diesel”.

Carbon negative is not necessarily ethically positive. Biofuel technology, perhaps, is not at the point where it can provide a long-term resource and still call itself sustainable. It just not might be “green” enough yet.