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Introduction and effective waste in the food system

The ongoing COVID-19 pandemic has reshaped the patterns of American life in unprecedented
ways and with stunning rapidity, resulting in many unintended, but not unwelcome, environmental benefits, as skies clear and animals venture into newly empty spaces [1]. On the other hand, the pandemic has also resulted in what appears to be (and is) a shocking crisis of food waste: Acute demand shocks from the almost overnight shift away from food consumption in suddenly closed restaurants and large institutional settings (including schools, universities, and many places of business) towards in-home consumption have resulted in the well-publicized farm-level wastage of whole fields of fresh produce, and the dumping of millions of gallons of fresh dairy [2].

Without commercial customers or the means to quickly reorient to retail supply chains,
and with limited on-farm storage capacity, some farmers have been forced to plow crops under,
bury already harvested produce, or dump milk into manure lagoons. With slaughterhouses now
reeling from COVID-19 as well, slaughter numbers are down and the dire prospect of millions
of livestock meeting their end on-farm without ever reaching a plate is raised, and the USDA now projects Americans will actually decrease their meat consumption in the coming year [3].
And yet, shocking images of rotting crops and animal culls belie a US food system that has long
ultimately wasted, in one form or another, the vast majority (perhaps as much as 80-90%) of all
food calories produced at the farm level, with dramatic consequences for the environment and
both animal and human health and well-being, while the pandemic could paradoxically spur beneficial changes that mitigate such waste.

This effective waste occurs in three major forms [4]:

1. Waste, per se: Waste occurs as both direct wastage upstream and downstream of the
   farm gate, but in the US, waste predominantly occurs at the level of restaurants and residences. Overnutrition, i.e., the overconsumption of food that can cause obesity and
   associated health problem, is in a very real sense is just as wasteful as discarding food
   directly and is also a large component of effective waste in America.
2. Biofuels (mainly corn ethanol and soy biodiesel) and other non-food uses: Via such “renewable” fuels, vehicle engines in America consume more human-edible calories than
   humans themselves, and yet displace only a tiny fraction of fossil fuel energy with few if
   any environmental benefits and clear harms.
3. Animal products (meat, dairy, and eggs): In modern production systems, massive quantities of otherwise edible food are fed to animals with less than 10% ultimately “processed” into an edible animal product, and so animal products generally represent a remarkable amount of embodied waste (though this varies between product, with beef generally worst and eggs perhaps best). While non-human edible food such as grass and other forage can be converted into animal biomass, this conversion is less efficient, already uses around a quarter of global land, and can only provide a very small amount of meat to diets.

Globally, about 6,000 edible calories per person per day are produced, but only around 2,500
reach plates; the difference is attributable to the wastes above, with each category roughly equal in magnitude, though biofuels are least important globally [4]. Simply halving waste, biofuel, and animal consumption could therefore yield sufficient calories for over another five billion people, and thus, there is no in principle reason why the current food system cannot feed the world now or in 2050.

In North America, the  figures are even more dramatic: Closer to 19,000 kcals per person per
day are produced at the primary crop level, with biofuels, net animal losses, and various waste
all again accounting for roughly 4,000 kcals [4]. The US has the most productive agricultural system on the planet, and a back-of-the-envelope calculation suggests all these lost calories could feed at least 1.5 billion humans. Agriculture as a system is also a leading threat to biodiversity, wild land, climate change, and multiple other “planetary boundaries” under threat by human activity [50, 5].

With the shocks of the pandemic, there may be a unique opportunity to address all the
above drivers of effective waste, and indeed most are in flux in largely uncontrolled ways. Economic crisis, frugality, and changing consumption habits could decrease direct wastage, biofuels production is falling along with transportation demand, and meat consumption and production is down for the first time in years. Capitalizing on these trends in more conscientious ways, both at the level of individual consumers and policy, seems essential to mitigating the harms of agriculture and feeding the future world. It is the goal of this post to develop a deeper understanding of these forms of waste, how they are shifting acutely, and the broader environmental motivations for sustained change.

Direct waste and overnutrition

Waste, per se, is the most obvious form of, well, waste. At the global scale, roughly a quarter of the food supply (i.e. food sufficient to feed two billion people) is lost as waste at various points in the supply chain [6], including harvesting, postharvest, processing, distribution, and retail and consumer level wastage. While globally pre-consumer waste is more important, American consumers are chiefly responsible for waste in this country: Conrad and colleagues [7] recently estimated that consumers waste about one pound of food every single day, on average, representing 30% of dietary calories, 25% of food weight, and the yield of around 30 million acres of cropland, and the USDA has previously estimated that 21% of food reaching the retail level, by weight, is wasted by US consumers [8].

 

The effects of a shift towards in-home food consumption, along with the general economic trends accompanying the pandemic, are not entirely clear, but there is reason for optimism. Restaurants are known to be extremely wasteful, with much food left uneaten and significant waste occurring upstream of the customer’s plate, not to mention inflated portions that, even if consumed, represent a major source of overnutrition. Overall, an estimated 22-33 billion pounds of food are annually wasted directly by restaurants, plus another 7-11 billion pounds wasted by institutions [9]. Though most estimates do not distinguish between consumer-level waste in-home and out-of-home, the USDA estimated that consumers discarded about 90 billion pounds of food in 2010 [8]. Combining the above numbers suggests 32-49% of waste occurs away-from-home, and since Americans took 34% of their calories from away-from-home meals in 2012 [14], we may infer that waste is probably greater in such settings. It should again be emphasized that overconsumption of calories and fat also has the potential to fall with a shift towards in-home meals.

Still, in-home waste is the largest single source of food waste in the US [9], and as much as 30% of edible food may be thrown out in residences. However, some news reports [15] point to glimmers of a new ethos of frugality that may be altering the hitherto wasteful habits of consumers at home. The extent to which mothers would go to stretch foodstuffs during the Great Depression is the stuff of legend, and surveys after the 2007-2009 Great Recession show increased interest in avoiding food waste [16]. The Great Recession was also associated with more meals taken at home and decreased expenditures on food away from home [14], and it seems likely that economic downturns and/or food prices should in general promote frugality and waste avoidance. In the 1970s, when food accounted for a larger proportion of household expenses (and the Depression and war years may have figured more strongly in living memory), US households wasted only about half as much food as they do today [9]; internationally, consumer food waste clearly increases with affluence [10]. The pandemic has led to an unprecedented unemployment crisis, economic uncertainty and a falling GDP, and while retail prices are down overall [11], food prices have increased somewhat, especially for beef and other meats [12]. Thus, economic conditions in addition to the extraordinary pandemic conditions could alter waste and habits for some time to come.

Biofuels and ethanol

Biofuels and animal feed, the two major indirect ways in which edible food is “wasted,” are also in flux. Consider first that US corn—the number one crop in the US, in terms of harvested
area, tonnage, and crop energy harvested—goes overwhelmingly towards these two ends: In recent years around 4,500 corn calories/person/day have gone toward each end (i.e. a total of about 9,000 calories/person/day, or about 90% of domestic corn use) [13]. The US Renewable Fuel Standard mandates certain amounts of “renewable” fuels, mainly corn ethanol, be blended into the gasoline supply. However, given that it represents such a large use of otherwise edible food energy, embodied farmland, and all the water, fertilizer, energy inputs, etc. required for production, ethanol has proven very controversial among environmentalists.

From an energy standpoint, ethanol is deeply suspect: around 1 million barrels per day of
ethanol were blended into the US fuel supply the last couple years [24], but this represents only
about 1% of all US primary energy consumption, and less than 5% of transportation energy [25]. Moreover, it actually takes nearly as much nonrenewable energy to produce and process ethanol as one actually gets out of the whole process, such that the overall ratio of energy out to energy in (known as the “energy return on investment” or EROI), is most likely no better than 1.3 [17, 18]; in other words, to get four units of ethanol we need three units of fossil fuels, and so ethanol can only be really considered to provide maybe 0.3% of primary energy. But even this is optimistic, for it has been pointed out that any major energy source must have an EROI much greater than one to be considered a net energy source for society writ large, given the energy needed to maintain the basic industrial, transportation, etc. infrastructure [19]. From this perspective, ethanol is most likely a net energy drain on the larger fossil energy system, and in any case cannot possibly serve as a significant replacement for fossil fuels.

Given this abysmal energy accounting, the only possible justification for ethanol would be
lower greenhouse gas (GHG) emissions over its lifecycle, but even this is unlikely. The EPA
estimates that a natural gas dry milling plant (a majority of US ethanol is now produced by dry
milling) in 2022 would have 21% lower lifecycle emissions than gasoline [20]. But other analyses are much more pessimistic, with some arguing nitrous oxide (a greenhouse gas) emissions
from nitrogen fertilizer application could mitigate any other GHG benefits [21], while carbon released from direct and indirect land use changes may be especially important. Converting
grasslands and forests to crops releases large amounts of carbon, and ongoing tillage operations can undermine soil carbon stores, and Searchinger and colleagues [22] estimated that it would take 167 years to pay back the “carbon debt” incurred from grassland conversion for ethanol.

These are not just theoretical concerns, as studies [23] have found that high commodity prices for corn and soy, largely attributable to biofuel demand, have indeed driven recent corn/soy expansion into formerly uncultivated grasslands, and that moreover, these lands are of more marginal quality, vulnerable to drought and erosion, and less productive. Such activity incurs not only a carbon debt but also harms natural ecosystems and biodiversity, while competition between food and ethanol can also drive indirect land use changes [22, 23]. Finally, as a practical matter, blending ethanol with gasoline is limited to about a 10% ethanol blend, and so even if we assume ethanol is 20% less GHG-intensive on an energy basis, an E10 blend results in carbon emissions savings of less than 1.5% over the lifecycle (not 2%, because ethanol carries less energy than gasoline). It seems that all this is hardly a worthy return on food energy sufficient to feed the US population twice over, and grown on over 30 million acres of land.

US gasoline consumption collapsed in late March and early April to levels not seen since the late 1960s, and despite recent upticks, demand remains about 30% lower than expected for this time [24]. The collapse in US gasoline demand has simultaneously, and in very straightforward fashion, cratered ethanol production, which, as of the week of May 15, remains more than 30% lower than before the crisis [24].

Animal Products

And now, to animal products. Decreasing animal consumption is increasingly recognized as a way to increase the efficiency of the food system, spare agricultural land, and mitigate other environmental harms, with a recent review by Poore and Nemecek [26] concluding that a global shift to an animal-free diet could, at least in principle, spare 76% of global farmland and avoid 49% of food-related GHG emissions. As a system, animal products represent “processing” of food energy inputs and protein (mostly in the form of corn and soy, in the US) to a live animal, which is then processed to an edible retail product. There are large losses along this processing chain, such that, overall, no more than 10% of otherwise edible feed ends up reaching the plate [4, 36]. This conversion efficiency varies with animal product, being around 10-20% for pork,
poultry, and dairy (with poultry most efficient), but only about 3% for beef; eggs may be most efficient overall, retaining as much as 30% of protein [36].

Americans consume more animal protein per capita than any other country [30], and less plant-based protein [32]. The price of this protein is steep, for despite the fabulous productivity of American farms, calculations by Cassidy et al. [44] suggest that India, which has very low animal intake and is largely vegetarian, is actually slightly more productive than America in terms of how many people are ultimately fed per unit of cropland. Not only is the US pattern inefficient, but it is unhealthy: Replacing animal protein, especially processed red meat, with plant protein is associated with reduced death rates, and plant protein intake in general seems to have health benefits [38].

Shepon and colleagues [36] estimated that, overall, only about 7-8% of both calories and protein contained in animal feed are actually converted to an edible animal product in the US
system. Given its low conversion efficiency, shifting all feed used for beef production to poultry
could meet the protein requirements of 140 additional persons [36]. However, shifting to plant
proteins (mainly from legumes, such as beans, peas, etc.), has even greater potential to save
land, resources, and GHG emissions, and to feed more people [37, 36], not to mention avoiding
animal welfare issues raised by shifts to intensive broiler (meat chicken) and swine confinement production systems. Indeed, chicken has already surpassed beef as America’s most consumed meat, and over nine billion individual chickens are raised and slaughtered each year (about 28
chickens per person) [51], compared to “just” 33 million cattle (and about 130 million hogs)
[52]; the short lives these chickens lead are unenviable, to say the least, while beef cattle at least spend much life on pasture.

Note that, while cattle do consume a good deal of non-human consumable forage and grass,
high forage diets are generally less digestible than high grain diets. Thus, grass-finished beef
production (i.e. the cattle spend the last portion of their life on pasture rather than a feedlot, as
all cattle start on pasture) is even less efficient, requires more land, and generates more GHGs
(mainly methane) than grain-finished beef [33, 34], and so can not be considered a scalable
alternative. Other comprehensive reviews have found that beef generally has the highest per-unit land use and greenhouse gas impacts of any major protein source (among other environmental harms), while plant-based proteins generally have the lowest [26], and diets lowest in animal products of all kinds have the smallest environmental footprint [26, 35].

The meatpacking industry has been heavily disrupted by coronavirus outbreaks, resulting in acute production decreases. The USDA reports sharp reductions in prices fetched for steer,
the number of cattle slaughtered, and beef production for the first two weeks of May, with beef
production down about 25% compared to prior years [27]. Pork, chicken, and turkey production
are also all down, though egg and milk production appear to be minimally affected (projected
milk production is actually up slightly compared to early 2020 estimates) [28]. Thanks to
shortages and weaker demand, the USDA now projects US per capita meat consumption to
fall to a “mere” 217 pounds in 2020, down by seven pounds from 2019, and down by almost 10
pounds compared to prior projections for 2020 [3]. This is especially notable, as it breaks a five year trend of increasing per capita meat consumption in the US, which had reached an all-time high in 2019 [28], well in excess of any time in the last 110 years (USDA records go back to
1909) [29]. Thus, any increased media attention to vegetarian and vegan diets notwithstanding, America remains a nation of extreme meat eaters by both global and historical standards.

These numbers should also suggest the utility of a goal of reducing, rather than eliminating, meat consumption. If everyone reduced meat consumption by half, US per capita consumption would fall to an unprecedented low and yet still be safely above the world average [30], while sparing a large portion of US agricultural production; even small reductions in meat consumption would be very meaningful. It also bears emphasizing that meat, dairy, and seafood are wasted at high rates by consumers [8]: Simply eliminating such waste could reduce meat consumed by as almost third, with the same aggregate impact on food systems and the environment as one-third of the population adopting a strictly vegan diet. Interestingly, per capita meat consumption did transiently fall by as much as 20 pounds in the few years after the Great Recession [29], and most retail meat prices increased substantially in April of 2020 compared to 2019, with ground beef prices up 8.5%, for example [12]. Sales of plant-based meat alternatives, while still extremely small in absolute terms, are reported to be on the rise during the pandemic [31]. Thus, supply shortfalls, price increases, and possible general frugality and increased attention to waste and the ills of animal production systems could be capitalized upon to spark a general and sustained reduction in animal consumption.

Broader environmental context

It should be understood that reducing waste (in all its forms) in food systems is an environmental issue of paramount concern. Every bite of food (or gallon of ethanol) embodies a vast upstream environmental footprint in terms of land, water, energy, agrochemicals, and even GHG emissions. Of all human systems, agriculture is unique in the scale of its impact on global land and wildlife. Globally, the agricultural footprint has continuously expanded since the Industrial Revolution, to the point that over one-third of all ice-free land is now devoted to agriculture [40, 41]. This compares to well under 1% of ice-free land as urban, despite rapid global urbanization [39]; in the contiguous United States 55% of land is agricultural compared to about 3.7% urban [42]. Of agricultural land, around one-third is relatively intensively managed croplands (generally field crops raised on an annual basis in various rotations, such as corn or soy, where plowing/cultivation in the spring is followed by fall harvest), while the other two-thirds is pasture [40]. Both represent profound transformations of the native ecosystems they replace, most dramatically when forests are cleared for cropland or pasture, and such habitat loss/transformation is the leading global threat to wildlife [50].

Since the Second World War, total land area under cultivation has expanded modestly [43], and even slightly decreased in the US, but these lands underwent a profound shift in management to a model dominated by large use of external inputs, mainly fertilizer and pesticides, as well as improved seed varieties, mechanization, and increased irrigation; this shift to an intensive high input production model is broadly known as the “Green Revolution,” and it unequivocally succeeded in dramatically increasing crop yields and the global food supply [43]. It is largely thanks to this Revolution that so many calories are now produced, but it is thanks to the growing appetites of Man that so much is for naught. Indeed, yield increases for corn, wheat, and rice from 1965 through 2009 were calculated to roughly match the changing allocation towards animal products and biofuels [44]. Thus, much of the fruit of this intensification is lost, nor has it been without harms. While farmland extensification, i.e. expansion into new lands
has obvious harms, farmland intensification (roughly defined as increased input use to achieve
higher yields, but may also entail such practices as conversion of remnant semi-natural habitat
to crops) is also linked to reduced biodiversity [40] and large-scale declines across a wide variety of animals, especially birds and insects, across multiple continents [45, 46].

In North America, there are now three billion fewer birds than there were in 1970 [45]; this decline is mainly thought to be related to agricultural intensification across the continent, and the greatest declines are in grassland birds concentrated in the agricultural heartland. Insect populations have likewise suffered enormously, mainly due to intensive agriculture and pesticide pollution [46]. Such declines in animal abundance, or simply the number of animal individuals, are an underappreciated component of the current mass extinction event. Even common species not in any immediate danger of extinction are declining, and many local or regional populations have been completely lost [47]. In general, perhaps 60% of all animals have been lost since just 1970 [50], a phenomenon termed “defaunation” by some scientists, or more dramatically (but depressingly accurately) a “biological annihilation” [47].

The harms of agriculture are not limited to wildlife and land use, but extend to climate change, with agriculture and associated land use changes a major source of GHG emissions on
par or exceeding the transportation sector at the global scale [48] (though cars still handily win
out in the automobile loving USA [49]), as well as freshwater and other biogeochemical cycles.
Nitrogen fertilizer leads to atmospheric emissions of nitrogen oxide, while ruminants (mainly
cattle) and animal manure generate the very potent methane; conversion of native prairies
and forests results in large CO2 emissions, and tillage can release organic carbon from soils.
Plant nutrients, especially nitrogen and phosphorus, are fundamental to all agriculture (and plant life in general), and are now provided from synthetic sources in such scale as to represent
unprecedented changes to the biogeochemical nitrogen and phosphate cycles. In the US, runoff
of these nutrients in the heartland harms local water quality and ultimately leads to vast dead
zones in the Gulf of Mexico. These cycles, freshwater use, climate, land use, and biodiversity
have all been rather famously framed as components of a larger suite of “planetary boundaries” that human activity is pushing outside of a safe operating range [5].

Conclusions

At this point, I hope you are convinced of the enormity of the scale and global environmental
impact of the modern agriculture that grew out of the Industrial and Green Revolutions. This
system provides vastly more food energy in total, per area of land, and per person than any other time in history, and yet, as I have argued already, most of this abundance (especially, again, in America) is ultimately wasted, in one form or another. The bounty of the Green Revolution has gone largely toward massive increases in meat and animal product consumption, more recently and inefficiently to engines as biofuels, and to the increasingly wasteful habits of consumers.

Curtailing such waste by reorienting our habits as a people and the systems that serve us is the best chance to mitigate the harms of agriculture and to feed the world in the decades to come. Many of the changes wrought by the pandemic may be forcing these changes, but for any benefit to persist will require more deliberate action in the future. Still, the pandemic has, more broadly, created the conditions for re-imagining the future, with new possibilities
unimaginable just months ago. The perils of this new plague have created, at least in some, a new consciousness that our actions now affect the future, and that collective sacrifice in service of the future can be worthy even in the face of economic upheaval. With respect to the most prominent environmental crisis of our time, climate change, the world is on track for what is  likely the largest ever annual reduction in carbon dioxide emissions (8% decrease) since the Industrial Revolution began [53], actually putting the world on the track to limiting global warming to 1.5 deg. C [54].

Whether these gains (i.e. reductions!) shall form the basis for a new collective path, or
be merely represent a curious divergence from business as usual, has yet to be seen. I argue
that transforming agriculture is as urgent a problem as the climate crisis, and that addressing
the aforementioned sources of effective waste can form the core of such an effort. As human
societies engage in a kind of great pause, there is an opportunity reconfigure how societies use
energy, land, and, perhaps especially, engage with the food systems that form the basis of all
civilization.

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