Chemical fertilizer is a climate disaster. Can high-tech biology fix it?

Canary Media’s Eating the Earth column explores the connections between the food we eat and the climate we live in.

Almost everything about synthetic fertilizer sucks.

It sucks for the climate, generating 2.5 percent of the world’s greenhouse gas emissions, more than global aviation. It sucks for the environment, creating a dead zone the size of Connecticut in the Gulf of Mexico while choking the Great Lakes with algal blooms. And it sucks for farmers, because it’s an expensive commodity controlled by petro-giants like Koch Industries and petro-states like Russia — and about half its nitrogen gets wasted.

The one thing about it that doesn’t suck is that it feeds the world. There are now 8 billion people on Earth, and the scientific literature suggests that if we didn’t have synthetic fertilizer to supersize our harvests, nearly 4 billion of us wouldn’t be alive. It’s possible that no 20th-century invention — not air conditioning, not television, not the atomic bomb — has been more consequential to more people than the ​“Haber-Bosch” industrial process that two German chemists devised to alchemize nitrogen from the air into nitrogen fertilizer for our crops.

As I’ve mentioned in every Eating the Earth column since the first one, the farming challenge of the 21st century will be to keep feeding the world but without frying the world, which will require at least 50 percent more food production with at least 75 percent fewer agricultural emissions. That means we can’t stop giving our crops the nitrogen they need to maximize their growth, but we also can’t keep broiling the planet with so much chemical fertilizer we manufacture from natural gas. The world needs to find a more sustainable nitrogen delivery system, and a fast-growing Berkeley-based unicorn called Pivot Bio, backed by green investors like Bill Gates and Al Gore as well as unsentimental agribusinesses like Bayer, Bunge and Continental Grain, believes it’s invented one.

Pivot Bio sells genetically edited microbes designed to pull nitrogen out of the air and feed it to crops, while making sure the nitrogen actually fertilizes the crops instead of escaping to the environment. And farmers are buying them. Pivot’s biological replacements for chemical fertilizers were applied to more than 5 million acres of American farmland last year, producing more than $100 million in revenue for the company. Pivot’s scientists claim their bugs can replace about 20 percent of a cornfield’s fertilizer without reducing yields — and considering their adoption has soared more than fifteenfold in the four years they’ve been on the market, farmers don’t seem to think they suck at all.

Nitrogen fertilizers emit nitrous oxide, a greenhouse gas 265 times as potent as carbon dioxide, so using less of them clearly helps the climate. But replacing one-fifth of the fertilizer on one-twentieth of one country’s corn acreage just as clearly won’t help much. In 2022, the emissions avoided by U.S. farmers using Pivot would have offset the electricity use of fewer than 50,000 homes. The company needs to get its microbes onto more acres of more crops in more countries to make a significant dent in the fertilizer problem, which is why its co-founder and CEO, bioengineer Karsten Temme, is shifting on Tuesday to a role as chief innovation officer, turning the CEO role over to an agribusiness veteran, Chris Abbott of Continental Grain.

“The story’s just getting started,” Abbott said in a joint interview with Temme. ​“The challenge we face now is: How do we get this in the hands of every grower out there?”

There’s an old joke that a farmer’s top three priorities are yield, yield and yield. Some scientists remain skeptical that Pivot’s biological solutions can replace chemical solutions on a grand scale without hurting yields. But so far, most of Pivot’s customers are coming back for more, which suggests they’re seeing financial benefits. Those benefits could increase if more countries crack down on nitrous oxide, as the Dutch government did in January. And the economics could become even more favorable as fledgling carbon markets begin to reward farmers for reducing emissions from fertilizer use.

In fact, what’s exciting about Pivot Bio is not only its potential to help fix the messy problems of fertilizer, but also its potential to help fix the messy problems of those scandal-plagued carbon markets.

Nitrogen is all around us. It makes up about 78 percent of our air. But it’s not in the form that crops need to grow, which is why we’ve always sought alternative forms to boost the fertility of our soils. In the 19th century, demand was so intense that two wars were fought over some South American islands renowned for their nitrogen-rich bird poop known as guano. The Haber-Bosch process created a more reliable source of usable nitrogen, but it’s not good that it’s so dependent on fossil fuels, and it’s even less good that half the nitrogen in chemical fertilizer is lost as greenhouse gases or water pollutants.

The U.S. agricultural community has tried to educate growers to use fertilizer more efficiently; for example, nitrogen applied in the fall often gets lost as runoff before crops are even planted in the spring. Precision technologies have also helped reduce waste, such as slow-release fertilizers that feed crops more gradually and GPS-enabled tractors that only drop fertilizer where it’s needed. But there’s still a lot of waste, which means a lot of nitrogen is still leaching into the environment rather than fertilizing crops.

Temme and his grad-school lab partner Alvin Tamsir founded Pivot Bio in 2011, with seed money from the Gates Foundation. Their initial plan was to reengineer crops like corn and wheat to self-fertilize by extracting nitrogen from the air, as legumes like soybeans and peas already do. But it didn’t work. Instead, Pivot’s team found soil microbes that already knew how to fix nitrogen from the air to feed plants, but no longer did because they were surrounded by nitrogen from fertilizer. Pivot figured out a way to edit their DNA so that they could no longer sense all the nitrogen around them in the soil — basically, so they would stop being lazy and start expending energy to fetch their own nitrogen. That worked.

I first visited Pivot in Berkeley in 2019, when it was testing its first product on 10,000 acres of Midwestern cornfields, and Temme was starting to plot his assault on the $200 billion fertilizer industry. He had raised $85 million and hired 70 employees; he was about to move his headquarters to a larger space across the street. And he was fired up about his microbes, which spoon-fed nitrogen to crops throughout the growing season, so that none of it would volatilize into the air or run off into water bodies. He showed me photos on his phone of healthy-looking corn treated with Pivot alongside slightly shorter and yellower stalks that had lost conventional fertilizer to spring flooding. A tablespoon of Pivot’s microbial powder could treat 5 acres of corn, and Temme intended to find new microbes that could help new crops.

“The 20th century was chemistry. The 21st century will be synthetic biology,” he told me. ​“We can reverse-engineer the incredibly sophisticated work that nature’s been doing all along. And we can avoid these big and bulky and expensive fertilizers that pollute the earth and even, you know, explode.”

Temme made a lot of big promises — Pivot would be on millions of acres in a few years, its corn product would be tweaked so it could be applied directly onto seeds, it would debut a new product for sorghum and other small grains — and they sounded like classic startup rhetoric. But they all have come true. He’s now raised more than $600 million and hired almost 500 employees.

The company documented its performance on hundreds of thousands of acres last year, and it says corn treated with Pivot had 12 percent more biomass and 14 percent more nitrogen than conventionally fertilized corn.

James Backman, a 26-year-old Minnesota farmer whose family sells Pivot Bio products, used them to replace 40 pounds of conventional fertilizer per acre on 2,000 acres of his own cornfields last year, with no yield losses. He says he saved money overall, because fertilizer prices spiked after Russia invaded Ukraine and squeezed natural gas supplies, but the real benefits came when heavy rains began washing away fertilizer but not his microbes.

“Forty pounds isn’t as sexy as it needs to be for some people, because they’ve still got to buy a lot of fertilizer and they’re not boosting their yields. But a 6-inch downpour is a real good sales tool,” Backman says. ​“Then the growers start telling you, ​‘Hey, I can see where my Pivot’s at!’”

Pivot’s results have not been peer-reviewed, and some scientists remain skeptical that farmers can trust it to replace conventional fertilizer. A North Dakota State University review of several field trials of Pivot’s PROVEN 40 corn product concluded that in most cases it had no yield benefit. Pivot’s defenders point out that it’s not supposed to be a yield product, just a fertilizer replacement, but the jury is still out.

“They promise a lot, but with fertilizer, you know what you’re going to get, and I don’t see that with the living organisms,” says Daniel Kaiser, a University of Minnesota professor who says PROVEN 40 only performed as advertised in one of six sites he tested. ​“It probably works, but not on every acre.”

Fred Below, a University of Illinois crop physiologist who’s advising Pivot, says he documented over a four-year experiment that the company’s first-generation product replaced at least 25 pounds of fertilizer per acre without yield loss. Still, everyone agrees more science is needed, which is why Pivot is collaborating with 22 universities on studies this year.

“The growth has been astounding, both the scale and the speed, and it’s exciting to see it moving beyond early adopters to a broader swath of farmers,” says New York University environmental studies professor David Kanter, a nitrogen expert who’s also a Pivot adviser. ​“But I keep telling them, you need to address these concerns in a way that’s beyond question, because there are still questions.”

Still, farmers aren’t idiots, and the fact that so many of them have been expanding their Pivot buys is probably the best evidence so far that it’s working. The company’s net revenue from its 2020 and 2021 customers almost tripled in 2023.

And Backman expects the value proposition to improve dramatically if future versions of PROVEN 40 can replace a much higher percentage of fertilizer without a yield drag, if American regulators start cracking down on nitrogen pollution, and especially if farmers can get compensated in the carbon markets for reducing their fertilizer use.

“If the markets can cover half the cost of Pivot Bio, or even all the cost, then it’s straight to the moon, you’ll see an unbelievable shift with farmers,” Backman says. ​“I mean, that’s game over.”

Speaking of things that suck, the early carbon markets have been a joke.

Carbon offsets are inherently controversial because they allow airlines, oil companies and other corporations to buy someone else’s emissions reductions instead of reducing their own emissions, as if they were medieval Catholics buying papal indulgences to greenwash their sins. The additional problem with today’s offsets is that the emissions reductions keep turning out to be bogus. There have been offsets for installing solar arrays that would have been installed anyway, protecting forests that would have been protected anyway, and sequestering carbon in farm soils that can’t be measured accurately.

By contrast, the emissions reductions when a farmer uses less fertilizer are tangible, measurable and easily verifiable. Pivot Bio has begun to broker deals that compensate farmers for those reductions — not through offsets, where an unrelated company buys a credit so that it can keep emitting, but through ​“insets,” where a company that ends up using the crop pays to reduce emissions in its own supply chain. For instance, a beverage company is buying PROVEN 40 directly for four Kentucky corn growers to produce climate-friendlier mash for its bourbon. The beverage company will get to count the reduced nitrous oxide emissions toward its global climate goals while the farmers will get free nitrogen. Pivot is also finalizing similar insetting deals with a beer company, a grain aggregator and an ingredients company. And it’s paying farmers to collect data on their fertilizer use, which could pave the way for more credible offset deals in the future.

This would be a fairly straightforward path to reducing agricultural emissions, but right now the world is heading down a different path, encouraging regenerative or organic practices that use fewer or no chemicals, and purportedly draw down carbon from the atmosphere into the soil. The European Union has set a goal of making one-fourth of the continent’s farms organic by 2030, while the Biden administration is pouring federal cash into ​“climate-smart agriculture” with a heavy focus on regenerative carbon farming. The carbon markets are also pushing reduced tillage, cover crops and other regenerative practices that are supposed to help reverse climate change by sequestering soil carbon.

I keep promising to devote an entire column to carbon farming, but for now let’s just say there’s limited evidence that no-till farming or cover crops increase the carbon content of agricultural soils, while there’s substantial evidence that kinder and gentler farming can reduce yields. That means it requires more land and more deforestation to produce the same amount of food. Forcing more European farmers to go organic and fertilizer-free could force Europe to increase its imports to maintain its food supply, which could outsource pollution, deforestation and emissions to the developing world.

Technological solutions like Pivot’s microbes, or feed additives that get cattle to burp less methane, or bio-pesticides that can replace chemicals without hurting yields, could be a much more direct way to reduce agricultural emissions. They’re less alluring to international institutions or do-gooder foundations, because they don’t involve revolutionary visions of more natural approaches to agriculture, just simple entrepreneurial tweaks to the deeply flawed existing system. They don’t require farmers to reimagine their relationship to the land or develop new ways of extracting sustenance from the soil, just to buy an innovative new product that can help replace an unsustainable existing product.

Everyone knows the industrialized global system of food and farming sucks. That’s going to be very tough to change. The way to start will be modest tweaks that can make it suck less.