I’ll start with two related thoughts, and then run with them. First, I’m thrilled by technology. It’s not I that I think technology will solve all our problems–I’m no determinist–but it’s just that I see technology as a vast arena of innovation, a place where humans can pour an abundance of natural creativity and, at times, reap substantial humanitarian and environmental rewards. In many ways, what makes life meaningful–what gives us pleasure and allows us to reach our potential as engaged human beings–is linked in one way or another to technological advancement. I’m well aware that technology is also the cause of immense suffering and ecological degradation. Nevertheless, there’s no disentangling humanity from technology. Systematically meddling with natural resources is, for better or worse, an important part of what defines us as a species.

Second, I’m impatient with the idea that technological advance is somehow a deviation from what’s “natural.” This is a common rhetorical strategy used by the spokespeople in the sustainable food movement to deride many agricultural technologies as artificial and destructive. It’s also a questionable pretext for insisting that we must grow plants and fatten animals according to more “natural” or–big buzzword here–”holistic” methods, drawing upon processes that occur in nature without human intervention. It’s also an intellectually lazy understanding of nature. In this formulation, nature becomes something not only falsely segregated from technology (and thus from humanity), but it becomes something that we’re supposed to think of as inherently superior to “artificial”–i.e., processes designed with human participation. Yes, the buffalo once fertilized the land that produced the grasses that fed buffalo when there were very few people around North America. That was natural, we’re told. But more people are now here. Billions more. And agriculture has to feed them. So it’s time for a new natural.

I’ll concede that my heart pulls toward the romanticized preference for natural methods. And the fact is this preference would be fine if there weren’t 7 billion people living on earth, with about two billion more on the way, and billions more on the verge of entering the middle class. But, as it now stands, to allow nature to be our farmer–which is what the sustainable food people say should happen–is to promote two of the more dangerous aspects of agriculture: systematic animal exploitation and gross inefficiency in plant production. Indeed, it’s a central tenet of the sustainable food movement that responsible and “natural” agricultural systems require the incorporation of domesticated (and thus genetically exploited) animals to enhance soil quality. Similarly, it’s a central tenet that plants should be grown without any synthetic fertilizer or fossil fuel. These flawed tenets are directly related to each other. In other words, reliance on exploiting animals is precisely what allows advocates of “natural” farming to justify avoiding synthetic fertilizer or the natural gas used to produce food. Take animals out of the agrarian equation and you have to acquire soil fertility in other ways. So, how does the ethical vegan respond to this quandary?

I’m becoming well aware of veganic agriculture. And I have hope for veganic agriculture. I imagine that–though technological progress–we may one day be able to create a global plant-based agricultural system using green manure and other non-synthetic enhancements. For now, though, my response cannot be so idealistic: if we want to take animals out of agriculture, we’re going to need to use fossil fuel and synthetic fertilizers–and even some level of pesticides and fungicides–to feed billions of people a plant-based diet devoid of intentional animal exploitation. I realize that this assessment might not sit well with many vegan advocates–who tend to be environmental advocates as well as animal advocates–but keep two things in mind: a) manipulating the environment to make it feed billions of people will always come at some cost (people who talk about a “free lunch” in agriculture–ahem, Pollan–are dreaming), and b) there are, with technology, remarkably encouraging ways to minimize the impact of these necessary synthetic inputs.

So here are a few reasons why I think it’s possible–and desirable–to remove animals from agriculture, produce enough food to feed 9 billion people, use fossil fuels and other synthetic inputs, and still have an environmentally responsible agricultural system.

–The overwhelming source of fossil fuel consumption in agriculture today is animal based agriculture. All that corn and soy is mainly the problem. Switching to a diverse agricultural system that produces plants for people to eat would dramatically reduce the need for fertilizer and fossil fuel, to the point that the environmental impact would be greatly minimized. Again, to think that any system of agricultural production in the modern world can break even in terms of energy costs is crazy talk. Holistic/sustainable advocates fail to calculate the energy wasted and required to remove an animal from a holistic system prematurely, not to mention killing, commodifying, and replacing her. As the World Preservation Institute reported late last year: a global vegan diet would reduce greenhouse gas emissions in agriculture by 94 percent. What more needs to be said?

–High end synthetic fertilizers can be extremely efficient when it comes to plant nutrient uptake–often more efficient than manure. In fact, customized fertilizers deliver more nutrients more efficiently than manure, which–not being in any way designed for the specific nutrient needs of the crop–has high rates of nutrient run off. Plant biologists have made great strides in matching crop nutrient needs with specific fertilizer profiles–but, they’ve only done this with corn and soy. What if we did it for 500 edible plant crops and grew them all in the United States? “That’s not natural,” the sustainable agrarians would say. To which I would respond: “Agriculture is not natural by your definition. Get over it.” Subsidizing the judicious use of these fertilizers makes more sense than subsidizing corn and soy production. The use of efficient, high grade, low run-off fertilizer could–calorie per calorie–be more environmentally sound than using loads and loads of composted manure or relying on rotational grazing.

–A plant-based system that eliminated animals would require much less agricultural space, an acute factor given the press on limited arable land globally. Rotational grazing gets people excited because it’s so “natural,” but there’s nothing terribly natural about chopping down rainforests to clear land so we can fatten animals and grow crops “holistically.” The only viable objection I ever get to this claim suggests that, under holistic systems, we would not need as much land because people would eat less meat. But this objections fails on at least two grounds. First, it’s naive to think that consumers are going to switch to more expensive animal product options so long as cheaper ones are available–and cheapness comes from industrialization. Two, and relatedly, eating limited animal products produced in holistic systems will become the domain of the elite. I see no reason to reform a food system so that wealthy people are the only ones able to eat in a way that supposedly respects the environment and the welfare of animals.

–Finally, advocates of sustainable agriculture support the holistic model because it theoretically eliminates dependence on fossil fuels. While I’ve already mentioned many problems with this goal, there is one that I haven’t mentioned that’s more important than all put together: the worth of an animal’s life should never be measured in barrels of oil.