In the modern world, food means fertilizer. Everything from a bowl of breakfast cereal to a curry relies on abundant use of synthetic fertilizer to raise crops or livestock. (The one notable exception, seafood, has its own carbon and sustainability problems). Over the last century, fertilizer use has enabled an unprecedented increase in human population and well-being. Average per-acre corn yields, for example, rose from 25 bushels in 1926 to 170 in 2006—and food became relatively much cheaper. But the Green Revolution has been anything but green. Fertilizer is a product of the fossil fuel industry, releasing carbon dioxide during its manufacture and emitting nitrous oxide, a greenhouse gas with 300 times the warming potential of CO2. Globally, fertilizers are responsible for more than 2.6 gigatons of carbon emissions annually, more than global shipping and aviation combined.
Which leads to our present dilemma. How do we continue our extraordinary advances in nutrition and prosperity, worldwide, without digging ourselves deeper into a carbon hole?
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More (But Greener) Fertilizer
Is The Way Forward
1. We can’t do without it. After Sri Lanka restricted fertilizer use in 2022, it saved $400 million on fertilizer imports—but spent $450 million on rice imports as production slumped 20%, Vox reports. Moving to organic production for cleaner, more sustainable food makes matters even worse. A USDA survey of over 14,000 farms found that organic yields were 30 to 40% lower for crops such as wheat, corn, and soy. Fertilizer looks like it’s here to stay.
2. We can make it without fossil fuels. The good news is that we can clean up fertilizer’s supply chain. Most hydrogen is currently produced from natural gas (methane) using a dirty, inefficient process with significant CO2 emissions. But hydrogen can also be made using electricity to split water molecules into hydrogen and oxygen. If that electricity comes from a renewable source such as solar, geothermal, or wind power, the “green hydrogen” it produces will have almost no carbon footprint. There’s also the tempting possibility of mining natural “gold hydrogen” directly from the Earth. Although both processes are in the earliest stages of commercialization, they might scale rapidly with investment.
3. De-industrializing fertilizer. The Holy Grail for sustainable fertilizer is a formula that releases no greenhouse gasses and doesn’t involve an expensive industrial process. One promising route is biofertilizer—live bacteria that turns atmospheric nitrogen directly into ammonia for plants. Biofertilizers are ten times cheaper than synthetic fertilizers, and they are already in widespread use in Brazil. Another option is to source ammonia from municipal sewage rather than natural gas.
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No. Less Fertilizer (And Less Meat)
Is The Right Path
1. Not wasting a drop. We can easily use much, much less fertilizer than we do today. Precision agriculture uses polymer-coated controlled-release fertilizers that spoon-feed nutrients at a pace crops need. This means that more nitrogen goes into the plant itself, and less runs off to pollute rivers or escape as nitrous oxide. Controlled-release fertilizers can cut nitrous oxide emissions by 30% and decrease runoff by as much as 50%. Applying fertilizer only at the right time and in the right place can also reduce usage, by up to 50%. These practices would also save farmers’ money—key to a speedy roll-out.
2. Kicking our cow habit. If everyone was vegan, we wouldn’t have a fertilizer dilemma. Most nitrogen fertilizer in the US goes directly to the production of corn that is then used to feed cows. Cows burp and fart methane, take up tracts of land that could grow crops for humans (or biofuels), and to add insult to environmental injury, are a very inefficient source of calories. About 20% of people in the world are already vegetarian, and sales of plant-based foods are predicted to increase five-fold by 2030. But rising prosperity has also made meat more affordable: global meat consumption doubled in the 30 years from 1988 to 2018, and is still growing.
3. Switch to crops that don’t need it. We don’t just eat fertilizer, we wear it. Cotton requires large amounts of chemical fertilizers (as well as water and pesticides) to ensure high yields. Innovative cellulose-based textiles made from unfertilized wood and other plants could replace cotton in many garments. There’s even hope for food crops that could deliver big yields without fertilizer. Last year, Wired ran a story on a variety of indigenous Mexican corn that fixes its own nitrogen from the air and could be bred into commercial strains.
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What To Keep An Eye On
1. Smarter carrots. Biden’s Inflation Reduction Act earmarked $22 billion for regenerative agriculture last year with the goal of maintaining yields while promoting climate-smart farming. But some climate strategies conflict with traditional farm bills, says Ben Lilliston of the Institute for Agriculture and Trade Policy in The New York Times. “Large-scale commodity production requires a lot of fertilizer use and pesticide use,” he said. “The core farm bill programs that lock those systems in place are still there.” OECD governments provide around $600 billion of agricultural support each year (including fertilizer subsidies) that the UN notes contribute “only modestly” to the objectives of boosting crop yields and helping a just transition to more climate-friendly policies.
2. Stouter sticks. Will countries like the Netherlands and Canada really be able to regulate large reductions in fertilizer? If not, there are other paths to success. Researchers in Illinois have calculated that charging farmers a fee for nitrogen leaching could reduce fertilizer pollution by 20%, resulting in a range of environmental and health benefits. Some jurisdictions, including Florida, however, are actually rolling back fertilizer restrictions.
3. Vested interests. Farmers in Canada, the Netherlands, and New Zealand have already taken to the streets to protest planned reductions of nitrogen fertilizers, fearing lower yields and lost income. In Sri Lanka, the government was forced to pay farmers when their biggest cash crop, tea, suffered production shortfalls due to synthetic fertilizer bans. Ultimately the government rolled back its ban. Such protests, however, are likely only the tip of the political iceberg should food prices spike.
Image: ©Anthropocene Magazine