We Didn’t Pave Paradise, We Plowed It

Sorry Joni.

My last piece about cars sparing land got more attention than I expected (nice!) and received some thoughtful criticism from my friend Toby and a very angry reaction from a man named Geoffrey. They both took issue with my blinkered focus on energy production. Here’s Toby:

Most of horses’ land consumption comes from energy production (pasture), while cars’ production, storage, and maintenance contribute non-negligibly to their physical footprint, partly b/c the land cost of their energy is so low. The actual footprint of the Diablo Canyon nuclear plant dramatically undercounts the land surface area required by the cars it might power.

I countered that horses have their own unique land requirements. Just as cars need parking and junkyards, horses need stables and manure disposal services. And while producing horses doesn’t require building factories, it does entail feeding a mostly useless young animal for a few years.¹ But Toby is right that cars need more land than what we use to power them. They just don’t need that much.

Let’s take a look at global land use statistics. The Food and Agriculture Organization of the United Nations has a nice land use dataset based on satellite images from NASA and the European Space Agency. At the ever-helpful website Our World in Data, Hannah Ritchie and Max Roser simplified the FAO data into this pretty visualization. 

Hannah Ritchie and Max Roser (2013) - "Land Use". Published online at OurWorldInData.org.

You can see that agriculture takes up huge tracts of land—the equivalent of the Americas plus a large part of Asia—while our cities, towns, and roads (and anything else classified as an “artificial surface” by the FAO) have a footprint the size of Libya—just one percent of global land area.

These figures surprised me when I first saw them since I, like most people in wealthy industrial nations, spend almost all my time within that small purple zone. Living most of our lives within built-up areas screws up our perception of the environment. Since we’re rarely ever more than a few feet from a road or parking lot, we might assume, for example, that “we paved paradise” is an apt metaphor for what’s happened to the planet over the last few centuries. The reality is closer to “we plowed paradise.”

National data is more detailed, so let’s zoom in to the United States. Every few years, the United States Department of Agriculture produces a comprehensive review of U.S. land use based on satellite images, censuses, and on-the-ground surveys from other government agencies.

Like the world as a whole, the U.S. is dominated by agriculture, with urban areas and infrastructure taking up a relatively small amount of land. However, the USDA data leaves us with an annoying “other land” category, which includes some rural residential areas, as well as mines and quarries. To complete the picture, we can supplement the USDA report with American Housing Survey data on rural residential areas, an estimate of land used for the energy system from Bloomberg,² and this comprehensive report on land used for mining based on satellite images.

Keep in mind that much of this research overlaps with USDA classifications. For example, rural residential land can include some cropland, pasture, and forest, and lots of our energy infrastructure lies within urban areas and national defense and industrial areas.³ That means we shouldn’t add these up. If we did, we’d get a significant overestimate of 262 million acres, or 11.6 percent of total U.S. land area (7 percent if we exclude rural residential land, likely the largest source of error).⁴

It might also be surprising that the U.S. uses so little land for mining, and you might suspect that we’ve offshored our mining footprint. That is partly true—the U.S. is a net importer of minerals—but we remain a top mining nation. The countries that mine the most land are Russia, China, and Australia, which use 2.9 million, 2.6 million, and 2.1 million acres, respectively. The United States takes fourth place with just over 2 million acres. Humanity as a whole uses just 0.07 percent of the Earth’s land for mining.

So, our towns, cities, roads, and other hard infrastructure take up a relatively small amount of land, especially when compared to agriculture. And, as with cars and horses, the reason is energy density.

While our total energy consumption has massively increased since the Industrial Revolution, almost all of that growth was supplied by fossil fuels, which, since they are highly energy-dense and come from underground, don’t take up much land. Agriculture creates a different form of energy: food, which is very land-intensive (recall that we use over a third of the Earth’s land for farming). Humans need food. And historically, we needed horses and other beasts of burden, which also need food. Now we approach a general principle: when we replace things that eat with things that don’t, we save land. That is also why one of the best things you can do for the environment is to eat less meat.

So, Toby, we should have a blinkered focus on energy production because the vast majority of humanity’s land footprint comes from producing energy in the form of food.

And Geoffrey, if you’re reading this, I hope it makes you less angry with me.

1.

Regions

also pointed out that horse seats (i.e., saddles) use lots of leather, while car seats are increasingly going vegan.

2. This includes power plants, pipelines, wind/solar farms, power lines, waste storage, and oil and gas extraction sites and refineries.

3. I.e., areas administered by the Department of Defense and Department of Energy.

4. A 2015 study from the Bureau of Economic Analysis estimates that 6 percent of land in the lower 48 is developed, but excludes federally-owned land. You can also consult this Bloomberg analysis of the USDA data, which also excludes Alaska and Hawaii.