Bioenergy Can't Compete With Our Taste for Meat

Biomass fuels have long been hailed as a real solution to carbon emissions, and theoretically it makes total sense: If you grow crops like switchgrass to produce biodiesel, carbon that’s released from burning the fuel was old carbon dioxide that had been sucked out of the air, rather than “new” carbon released from burning fossil fuels. Basically, bioenergy production is a lot nearer to net-neutral than fossil fuels, and some startups like Cool Planet even claim they can make carbon-negative fuels.

Of course, even as the renewables market grows, some next-gen biofuel manufacturers are having trouble going commercial. In any case, bioenergy is still a small market sector, and as good as they sound (biofuels, for example, are an easier drop-in solution for cleaning up cars than developing new battery tech) they face an inherent conundrum: How, when our population continues to swell, can we grow more crops for bioenergy when we need farmland for food?

That’s the question posed by University of Exeter researchers Tom Powell and Tim Lenton in a new paper in Energy and Environmental Science. Their conclusion isn’t surprising: Worldwide, there’s already a ton of pressure to increase agricultural efficiency and produce more food, especially as the massive populaces of the BRIC countries become more affluent and demand more resource- and land-intensive products like meat.

Meat production is indeed land-intensive. The UN’s Food and Agriculture Organization (FAO) has noted that livestock production emits more carbon dioxide than transporation worldwide. The FAO also noted that the livestock sector is the fasted growing sector in agriculture, stating that:

With increased prosperity, people are consuming more meat and dairy products every year. Global meat production is projected to more than double from 229 million tonnes in 1999/2001 to 465 million tonnes in 2050, while milk output is set to climb from 580 to 1043 million tonnes.

The human population has more than tripled in the last 85 years, from 2 billion in 1927 to 7 billion today. That’s a whole lot of new mouths to feed, and data cited by Powell and Lenton state that agricultural enterprises now cover around 40 percent of the “productive terrestrial surface of the globe.” That’s even higher in the U.S.; a paper in the American Journal of Clinical Nutrition by David and Marcia Pimentel states that “The US food production system uses about 50% of the total US land area, 80% of the fresh water, and 17% of the fossil energy used in the country.”

Meanwhile, Powell and Lenton write that, with livestock production being the least-efficient agricultural sector, potential gains there are huge:

The efficiency of food production clearly has enormous implications for the future of the relationship between humans and the Earth. Grazing and fodder production currently account for around 60% of food related biomass harvest and 78% of agricultural land use. Since the livestock sector is the least efficient element of the food system, takes up the largest area of land, appropriates the largest portion of NPP, and generates the biggest residue streams, changes in this sector have the most
significant impact.

So, we need more land for food, but we also need to keep as much natural, productive land as possible lest we throw off the carbon cycle balance even farther. But if we need land for crops and carbon sinks, where do we find space for bioenergy crops? Powell and Lenton call it a “trilemma”:

However, these underlying objectives of preserving natural ecosystems and food production are arguably more fundamental than solving the climate problem, which sets up a 'trilemma': we already co-opt plants to produce food for us on a global scale, and growing biomass for energy (with or without carbon capture and storage) can conflict with food production. Furthermore, replacing natural ecosystems with biomass plantations in order to help solve the climate problem and thus preserve natural ecosystems would be an ironic Catch 22.

The duo lays out a few scenarios that could lead to carbon outputs decreasing and/or bioenergy crops becoming viable, and a number that don’t. But the crux of the issue is this: Agricultural production produces more carbon emission than does natural land, and we’re likely going to have to convert more land to food production as our population grows. That’s not to attack agriculture; we need food, and a lack of it is going to cause more trouble in the near term than climate change.

Still, our options to reduce ag’s impace are to either change our dietary habits toward less-intensive foods (e.g. eat less meat) or make those process more efficient. The first option isn’t particularly likely when you consider the world’s growing wealth and just how tasty meat products are. (Of course, there is potential from quality fake meat enterprises like the one funded by Biz Stone.) The latter is the more likely scenario, as Powell and Lenton note:

Our results show clearly that with the current dietary trend of increasing meat consumption, persisting with low-efficiency agricultural systems would be a catastrophe for natural ecosystems, eliminating the majority of them. It would also make future land use a major contributor to global CO2 emissions … Only in our high-efficiency agriculture scenarios can managed land be turned from a carbon source to a carbon sink. Our high-meat, high-efficiency scenario is probably closest to what has actually happened over the last 12 years, with global growth in meat consumption being largely met by pork and poultry rather than beef and estimated land use change CO2 emissions of 1.8 Pg C per year in the 2000s somewhat counterbalanced by forest regrowth and afforestation.

In short, in recent years we’ve increased agricultural efficiency as well as eaten more efficient meats, while also rehabilitating natural lands, which all works towards pushing our carbon emissions towards neutral. (We’re still not close, however.) But, broader climate implications aside, when we’re already trying to maximize the efficiency of our land now, and will surely need more cropland in the future, how are we going to find space to grow bioenergy crops?

Well, as energy demand also grows in the U.S., it’s likely that bioenergy production will increase, but still won’t be a major player in our energy landscape. This wonderful interactive infographic from the National Renewable Energy Laboratory says as much; even as renewables produce more and more of our nation’s energy, bioenergy is projected to go from nearly-nonexistent to a small, but respectable, piece of the pie by 2050. But even then the bioenergy sector would still pale in comparison to a shrinking fossil fuels market. So will bioenergy, as great as it can be, really help replace fossil fuels? As long as we have to eat, I think not.

Follow Derek Mead on Twitter: @derektmead.

• Booze-Pooping Microbes Might Just Save the Planet
• The Energy Fixers
• With Lo-Tech Pink Slime Gone, Where's the Synthetic Beef?