What revisions would I make to section II of A Vegetarian Sourcebook (AVS) on “Vegetarian Ecology,” if I were to rewrite it today? There are two levels of changes that I would make: first, updates to all the data I brought forward, and second, explaining our food problems in terms of ecological economics.

The basic information in section II actually doesn’t need that many changes. Livestock agriculture hasn’t changed that much in thirty years, so my overall analysis and even most of the data is still quite relevant.

Obviously it would be nice to update Table 13, “Agricultural land use in the United States in 1977” with more recent data. I’d need to do the same for Table 16, “World water use and consumption” (which gives 1970 data with projections for the year 2000), and similar tables. On the other hand, a lot of this data hasn’t really changed in a way that would affect the conclusions. A few weeks ago I started to recalculate agricultural land use in the United States for 2008, and I found that the basic numbers and percentages were much the same.

One interesting and more substantial change would be needed to the chapter on soil erosion (chapter 14), but in a way that actually strengthens my argument. In 1987, an important article appeared in the May-June 1987 issue of the Journal of Soil and Water Conservation: “Soil loss tolerance: fact or myth?” by Leonard C. Johnson. “Soil loss tolerance” is the amount of soil erosion that can be tolerated because it will be compensated for by the constant but very slow natural processes of soil formation. Leonard argues that the then-conventional measure of soil loss tolerance (and accepted by AVS) was far too optimistic, by about a factor of 10, because the process of soil formation was so slow. To make a long story short, the conclusions of this article are now widely accepted. We are losing soil at a rate 10-20 times faster than it is being formed in the United States, and it is even worse in Asia and Africa!

In addition, we’d need to add a chapter on climate change and vegetarianism, as well as another chapter on peak oil and vegetarianism. The discussion of energy and food (chapter 13) could be made much more extensive than it is to encompass issues surrounded the “local food” movement. The information available on these subjects has vastly increased in the last few decades.

However, there is a different type of complexity that would force me to organize the material differently. AVS does not take into account ecological economics. It addresses most resource questions in the same way that Diet for a Small Planet did — from the point of view of efficiency, arguing that a vegetarian diet is more efficient with respect to natural resources. But there is more to it than just efficiency. Ecological economics also involves questions of scale (how big can our agricultural system get?) and distribution (what about the social justice of the current system of food distribution?) as well. These are certainly related to the question of efficiency, but are different from it.

Our current environmental crisis has economic origins; the economy cannot handle “limits to growth.” This is not just an issue with the agricultural system, but the entire economy. Climate change is the most obvious example of a case of these limits; we only have so much air. We also only have so much oil, natural gas, water, soil, and forest land.

When we start to encounter these limits, our growth economy starts to fail. We have for all practical purposes already encountered limits to growth. This is the underlying problem behind both the financial crisis of 2008 and the recent debt ceiling crisis of 2011. “Peak oil” is the immediate problem, but if lots of cheap oil were to miraculously appear, other natural resources are waiting in the wings to appear as the poster child for natural limits.  Water and soil erosion, for example, would soon become prominent problems, and of course we would still need to deal with climate change.

The discipline of ecological economics was almost completely unknown in the 1980’s. AVS actually does try to address the question of scale (see pages 138-140), anticipating in some respects the concept of the “ecological footprint” which first became widely known in the 1990’s. Even today, ecological economists are a small minority of all economists, and the number of vegan ecological economists is even smaller than that. So “vegetarian ecology” is a much more difficult subject than “vegetarian nutrition,” where we have a large number of vegan experts writing and practicing their discipline.

To really update section II, we would need to understand our agricultural system in the context of the environmental crisis, the limits to growth, and ecological economics. This is a massive undertaking, but the world faces no more urgent issue at this time.