Biofuels and land use conversion II

Continuing the earlier post, below is Figure 3 from “Our share of the planetary pie,” a paper from the Proceedings of the National Academy of Sciences in 2007. The upper map shows the percentage of net primary productivity used by humans for food; the lower map shows the percentage of net primary productivity (NPP) used by humans for non-food and luxury crops such as cotton and coffee. See Figure 1 at the link for a map showing croplands and pastures.

A few things worth noting: compare human appropriation of net primary productivity (HANPP, the biosphere bounty humans skim off before flora and fauna can get it) in the US Northwest and Europe. Look at the equatorial regions, where most biofuel-related land use changes have and would occur and where most biodiversity lives. Look at Borneo, the big island northwest of Australia: the purple in the lower map probably represents palm oil plantations, which result in nearly 100% HANPP where they occur. In general, areas with no HANPP are tropical, temperate, or boreal forest, arctic/antarctic regions, or desert.

Biofuels and land use conversion I

Food vs fuel issues, and agriculture and use of agricultural products generally, are so complicated that they have emergent properties. We can think about them most easily by intentionally oversimplifying. So here goes.

Before the recent increase in expectations for biofuels as a solution for energy/global climate change problems, human appropriation of net primary productivity (HANPP) had reached a kind of equilibrium. (HANPP is the amount of biosphere bounty humans skim off the top, before flora and fauna get to dine.) Agricultural production has increased roughly in synch with population growth, mostly through improved plant breeding and agronomic practices. This has meant that large increases of farmland area haven’t been as necessary as they might have been without yield increases. Population growth is slowing, and most concern is about the consumption of material goods by people, not the number of people per se.

The difference now, post-biofuels, is that each gallon of biofuel consumption is equivalent to additional increases in population. A gallon of ethanol (the ethanol itself, not including production) contains about 90 MJ (21,500 kcal) of energy, enough energy for 10 days of a 2000 Calorie/day diet. For a gallon of biodiesel, then numbers are more like 140 MJ or 33,000 kcal — enough for over 2 weeks of human power.

I haven’t examined new reports from Europe about biofuels and indirect land use conversion, but increasing use of biofuels without decreasing overall energy use unavoidably leads to increasing land area in agriculture. New land is not being formed, so land use change is inevitable. This only makes intuitive sense. Of course there will be improvements — a recent news story suggested that limited replacement of corn with miscanthus (a hybrid grass) would have a variety of benefits, including increased ethanol production. However, there is a hard theoretical limit to possible increases.

By the way, use of non-food crops and materials for biofuels isn’t an improvement, from a biosphere/HANPP perspective. The problem is energy consumption, not biofuel production.

I think the real question is, what are the implications of apparently changing attitudes toward biodiesel for our regional biodiesel economy? How will we respond if and when European-style indirect land-use conversion concerns are raised here? See the next post for a map showing global HANPP for food and non-food crops — it will suggest why Europeans may be more sensitive to land use conversion issues than those of us in the US Northwest.

In the old days, I hoped that conceptual linkage between biofuels and food would cause people to examine their own energy consumption, rather than blame biofuels. Unfortunately, that doesn’t seem to be happening.