As the Popo Agie River wends its way down from the glaciers atop Wyoming’s Wind River Mountains toward the city of Lander, it flows into a limestone cave and disappears. The formation, known as the Sinks, spits the river back out at another feature called the Rise a quarter of a mile east, a little more voluminous and a little warmer, with brown and rainbow trout weighing as much as 10 pounds mingling in its now smooth pools. The quarter-mile journey from the Sinks to the Rise takes the river two hours.

Scientists first discovered this quirk of the middle fork of the Popo Agie (pronounced puh-po zuh) in 1983 by pouring red dye into the river upstream and waiting for it to resurface. Geologists attribute the river’s mysterious delay to the water passing through exceedingly small crevasses in the rock that slow its flow.

Like many rivers in the arid West, the Popo Agie is an important aquifer. Ranchers, farmers, businesses, and recreationists rely on detailed data about it—especially day-to-day streamflow measurements. That’s exactly the type of empirical information collected by the National Oceanic and Atmospheric Administration (NOAA).

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Along the country road that leads to ATL4, a giant data center going up east of Atlanta, dozens of parked cars and pickups lean tenuously on the narrow dirt shoulders. The many out-of-state plates are typical of the phalanx of tradespeople who muster for these massive construction jobs. With tech giants, utilities, and governments budgeting upwards of US $1 trillion for capital expansion to join the global battle for AI dominance, data centers are the bunkers, factories, and skunkworks—and concrete and electricity are the fuel and ammunition.

To the casual observer, the data industry can seem incorporeal, its products conjured out of weightless bits. But as I stand beside the busy construction site for DataBank’s ATL4, what impresses me most is the gargantuan amount of material—mostly concrete—that gives shape to the goliath that will house, secure, power, and cool the hardware of AI. Big data is big concrete. And that poses a big problem.

Concrete is not just a major ingredient in data centers and the power plants being built to energize them. As the world’s most widely manufactured material, concrete—and especially the cement within it—is also a major contributor to climate change, accounting for around 6 percent of global greenhouse gas emissions. Data centers use so much concrete that the construction boom is wrecking tech giants’ commitments to eliminate their carbon emissions. Even though Google, Meta, and Microsoft have touted goals to be carbon neutral or negative by 2030, and Amazon by 2040, the industry is now moving in the wrong direction.

Last year, Microsoft’s carbon emissions jumped by over 30 percent, primarily due to the materials in its new data centers. Google’s greenhouse emissions are up by nearly 50 percent over the past five years. As data centers proliferate worldwide, Morgan Stanley projects that data centers will release about 2.5 billion tonnes of CO₂ each year by 2030—or about 40 percent of what the United States currently emits from all sources.

But even as innovations in AI and the big-data construction boom are boosting emissions for the tech industry’s hyperscalers, the reinvention of concrete could also play a big part in solving the problem. Over the last decade, there’s been a wave of innovation, some of it profit-driven, some of it from academic labs, aimed at fixing concrete’s carbon problem. Pilot plants are being fielded to capture CO ₂ from cement plants and sock it safely away. Other projects are cooking up climate-friendlier recipes for cements. And AI and other computational tools are illuminating ways to drastically cut carbon by using less cement in concrete and less concrete in data centers, power plants, and other structures.

Demand for green concrete is clearly growing. Amazon, Google, Meta, and Microsoft recently joined an initiative led by the Open Compute Project Foundation to accelerate testing and deployment of low-carbon concrete in data centers, for example. Supply is increasing, too—though it’s still minuscule compared to humanity’s enormous appetite for moldable rock. But if the green goals of big tech can jump-start innovation in low-carbon concrete and create a robust market for it as well, the boom in big data could eventually become a boon for the planet.

Hyperscaler Data Centers: So Much Concrete

At the construction site for ATL4, I’m met by Tony Qorri, the company’s big, friendly, straight-talking head of construction. He says that this giant building and four others DataBank has recently built or is planning in the Atlanta area will together add 133,000 square meters (1.44 million square feet) of floor space.

They all follow a universal template that Qorri developed to optimize the construction of the company’s ever-larger centers. At each site, trucks haul in more than a thousand prefabricated concrete pieces: wall panels, columns, and other structural elements. Workers quickly assemble the precision-measured parts. Hundreds of electricians swarm the building to wire it up in just a few days. Speed is crucial when construction delays can mean losing ground in the AI battle.

The ATL4 data center outside Atlanta is one of five being built by DataBank. Together they will add over 130,000 square meters of floor space.DataBank

That battle can be measured in new data centers and floor space. The United States is home to more than 5,000 data centers today, and the Department of Commerce forecasts that number to grow by around 450 a year through 2030. Worldwide, the number of data centers now exceeds 10,000, and analysts project another 26.5 million m² of floor space over the next five years. Here in metro Atlanta, developers broke ground last year on projects that will triple the region’s data-center capacity. Microsoft, for instance, is planning a 186,000-m² complex; big enough to house around 100,000 rack-mounted servers, it will consume 324 megawatts of electricity.

The velocity of the data-center boom means that no one is pausing to await greener cement. For now, the industry’s mantra is “Build, baby, build.”

“There’s no good substitute for concrete in these projects,” says Aaron Grubbs, a structural engineer at ATL4. The latest processors going on the racks are bigger, heavier, hotter, and far more power hungry than previous generations. As a result, “you add a lot of columns,” Grubbs says.

1,000 Companies Working on Green Concrete

Concrete may not seem an obvious star in the story of how electricity and electronics have permeated modern life. Other materials—copper and silicon, aluminum and lithium—get higher billing. But concrete provides the literal, indispensable foundation for the world’s electrical workings. It is the solid, stable, durable, fire-resistant stuff that makes power generation and distribution possible. It undergirds nearly all advanced manufacturing and telecommunications. What was true in the rapid build-out of the power industry a century ago remains true today for the data industry: Technological progress begets more growth—and more concrete. Although each generation of processor and memory squeezes more computing onto each chip, and advances in superconducting microcircuitry raise the tantalizing prospect of slashing the data center’s footprint, Qorri doesn’t think his buildings will shrink to the size of a shoebox anytime soon. “I’ve been through that kind of change before, and it seems the need for space just grows with it,” he says.

By weight, concrete is not a particularly carbon-intensive material. Creating a kilogram of steel, for instance, releases about 2.4 times as much CO₂ as a kilogram of cement does. But the global construction industry consumes about 35 billion tonnes of concrete a year. That’s about 4 tonnes for every person on the planet and twice as much as all other building materials combined. It’s that massive scale—and the associated cost and sheer number of producers—that creates both a threat to the climate and inertia that resists change.

At its Edmonton, Alberta, plant [above], Heidelberg Materials is adding systems to capture carbon dioxide produced by the manufacture of Portland cement.Heidelberg Materials North America

Yet change is afoot. When I visited the innovation center operated by the Swiss materials giant Holcim, in Lyon, France, research executives told me about the database they’ve assembled of nearly 1,000 companies working to decarbonize cement and concrete. None yet has enough traction to measurably reduce global concrete emissions. But the innovators hope that the boom in data centers—and in associated infrastructure such as new nuclear reactors and offshore wind farms, where each turbine foundation can use up to 7,500 cubic meters of concrete—may finally push green cement and concrete beyond labs, startups, and pilot plants.

Why cement production emits so much carbon

Though the terms “cement” and “concrete” are often conflated, they are not the same thing. A popular analogy in the industry is that cement is the egg in the concrete cake. Here’s the basic recipe: Blend cement with larger amounts of sand and other aggregates. Then add water, to trigger a chemical reaction with the cement. Wait a while for the cement to form a matrix that pulls all the components together. Let sit as it cures into a rock-solid mass.

Portland cement, the key binder in most of the world’s concrete, was serendipitously invented in England by William Aspdin, while he was tinkering with earlier mortars that his father, Joseph, had patented in 1824. More than a century of science has revealed the essential chemistry of how cement works in concrete, but new findings are still leading to important innovations, as well as insights into how concrete absorbs atmospheric carbon as it ages.

As in the Aspdins’ day, the process to make Portland cement still begins with limestone, a sedimentary mineral made from crystalline forms of calcium carbonate. Most of the limestone quarried for cement originated hundreds of millions of years ago, when ocean creatures mineralized calcium and carbonate in seawater to make shells, bones, corals, and other hard bits.

Cement producers often build their large plants next to limestone quarries that can supply decades’ worth of stone. The stone is crushed and then heated in stages as it is combined with lesser amounts of other minerals that typically include calcium, silicon, aluminum, and iron. What emerges from the mixing and cooking are small, hard nodules called clinker. A bit more processing, grinding, and mixing turns those pellets into powdered Portland cement, which accounts for about 90 percent of the CO₂ emitted by the production of conventional concrete [see infographic, “Roads to Cleaner Concrete”].

Karen Scrivener, shown in her lab at EPFL, has developed concrete recipes that reduce emissions by 30 to 40 percent.Stefan Wermuth/Bloomberg/Getty Images

Decarbonizing Portland cement is often called heavy industry’s “hard problem” because of two processes fundamental to its manufacture. The first process is combustion: To coax limestone’s chemical transformation into clinker, large heaters and kilns must sustain temperatures around 1,500 °C. Currently that means burning coal, coke, fuel oil, or natural gas, often along with waste plastics and tires. The exhaust from those fires generates 35 to 50 percent of the cement industry’s emissions. Most of the remaining emissions result from gaseous CO ₂ liberated by the chemical transformation of the calcium carbonate (CaCO₃) into calcium oxide (CaO), a process called calcination. That gas also usually heads straight into the atmosphere.

Concrete production, in contrast, is mainly a business of mixing cement powder with other ingredients and then delivering the slurry speedily to its destination before it sets. Most concrete in the United States is prepared to order at batch plants—souped-up materials depots where the ingredients are combined, dosed out from hoppers into special mixer trucks, and then driven to job sites. Because concrete grows too stiff to work after about 90 minutes, concrete production is highly local. There are more ready-mix batch plants in the United States than there are Burger King restaurants.

Batch plants can offer thousands of potential mixes, customized to fit the demands of different jobs. Concrete in a hundred-story building differs from that in a swimming pool. With flexibility to vary the quality of sand and the size of the stone—and to add a wide variety of chemicals—batch plants have more tricks for lowering carbon emissions than any cement plant does.

Cement plants that capture carbon

China accounts for more than half of the concrete produced and used in the world, but companies there are hard to track. Outside of China, the top three multinational cement producers—Holcim, Heidelberg Materials in Germany, and Cemex in Mexico—have launched pilot programs to snare CO₂ emissions before they escape and then bury the waste deep underground. To do that, they’re taking carbon capture and storage (CCS) technology already used in the oil and gas industry and bolting it onto their cement plants.

These pilot programs will need to scale up without eating profits—something that eluded the coal industry when it tried CCS decades ago. Tough questions also remain about where exactly to store billions of tonnes of CO ₂ safely, year after year.

The appeal of CCS for cement producers is that they can continue using existing plants while still making progress toward carbon neutrality, which trade associations have committed to reach by 2050. But with well over 3,000 plants around the world, adding CCS to all of them would take enormous investment. Currently less than 1 percent of the global supply is low-emission cement. Accenture, a consultancy, estimates that outfitting the whole industry for carbon capture could cost up to $900 billion.

“The economics of carbon capture is a monster,” says Rick Chalaturnyk, a professor of geotechnical engineering at the University of Alberta, in Edmonton, Canada, who studies carbon capture in the petroleum and power industries. He sees incentives for the early movers on CCS, however. “If Heidelberg, for example, wins the race to the lowest carbon, it will be the first [cement] company able to supply those customers that demand low-carbon products”—customers such as hyperscalers.

Though cement companies seem unlikely to invest their own billions in CCS, generous government subsidies have enticed several to begin pilot projects. Heidelberg has announced plans to start capturing CO₂ from its Edmonton operations in late 2026, transforming it into what the company claims would be “the world’s first full-scale net-zero cement plant.” Exhaust gas will run through stations that purify the CO₂ and compress it into a liquid, which will then be transported to chemical plants to turn it into products or to depleted oil and gas reservoirs for injection underground, where hopefully it will stay put for an epoch or two.

Chalaturnyk says that the scale of the Edmonton plant, which aims to capture a million tonnes of CO₂ a year, is big enough to give CCS technology a reasonable test. Proving the economics is another matter. Half the $1 billion cost for the Edmonton project is being paid by the governments of Canada and Alberta.

ROADS TO CLEANER CONCRETE

As the big-data construction boom boosts the tech industry’s emissions, the reinvention of concrete could play a major role in solving the problem.

• CONCRETE TODAY Most of the greenhouse emissions from concrete come from the production of Portland cement, which requires high heat and releases carbon dioxide (CO₂) directly into the air.

• CONCRETE TOMORROW At each stage of cement and concrete production, advances in ingredients, energy supplies, and uses of concrete promise to reduce waste and pollution.

The U.S. Department of Energy has similarly offered Heidelberg up to $500 million to help cover the cost of attaching CCS to its Mitchell, Ind., plant and burying up to 2 million tonnes of CO₂ per year below the plant. And the European Union has gone even bigger, allocating nearly €1.5 billion ($1.6 billion) from its Innovation Fund to support carbon capture at cement plants in seven of its member nations.

These tests are encouraging, but they are all happening in rich countries, where demand for concrete peaked decades ago. Even in China, concrete production has started to flatten. All the growth in global demand through 2040 is expected to come from less-affluent countries, where populations are still growing and quickly urbanizing. According to projections by the Rhodium Group, cement production in those regions is likely to rise from around 30 percent of the world’s supply today to 50 percent by 2050 and 80 percent before the end of the century.

So will rich-world CCS technology translate to the rest of the world? I asked Juan Esteban Calle Restrepo, the CEO of Cementos Argos, the leading cement producer in Colombia, about that when I sat down with him recently at his office in Medellín. He was frank. “Carbon capture may work for the U.S. or Europe, but countries like ours cannot afford that,” he said.

Better cement through chemistry

As long as cement plants run limestone through fossil-fueled kilns, they will generate excessive amounts of carbon dioxide. But there may be ways to ditch the limestone—and the kilns. Labs and startups have been finding replacements for limestone, such as calcined kaolin clay and fly ash, that don’t release CO ₂ when heated. Kaolin clays are abundant around the world and have been used for centuries in Chinese porcelain and more recently in cosmetics and paper. Fly ash—a messy, toxic by-product of coal-fired power plants—is cheap and still widely available, even as coal power dwindles in many regions.

At the Swiss Federal Institute of Technology Lausanne (EPFL), Karen Scrivener and colleagues developed cements that blend calcined kaolin clay and ground limestone with a small portion of clinker. Calcining clay can be done at temperatures low enough that electricity from renewable sources can do the job. Various studies have found that the blend, known as LC3, can reduce overall emissions by 30 to 40 percent compared to those of Portland cement.

LC3 is also cheaper to make than Portland cement and performs as well for nearly all common uses. As a result, calcined clay plants have popped up across Africa, Europe, and Latin America. In Colombia, Cementos Argos is already producing more than 2 million tonnes of the stuff annually. The World Economic Forum’s Centre for Energy and Materials counts LC3 among the best hopes for the decarbonization of concrete. Wide adoption by the cement industry, the centre reckons, “can help prevent up to 500 million tonnes of CO₂ emissions by 2030.”

In a win-win for the environment, fly ash can also be used as a building block for low- and even zero-emission concrete, and the high heat of processing neutralizes many of the toxins it contains. Ancient Romans used volcanic ash to make slow-setting but durable concrete: The Pantheon, built nearly two millennia ago with ash-based cement, is still in great shape.

Coal fly ash is a cost-effective ingredient that has reactive properties similar to those of Roman cement and Portland cement. Many concrete plants already add fresh fly ash to their concrete mixes, replacing 15 to 35 percent of the cement. The ash improves the workability of the concrete, and though the resulting concrete is not as strong for the first few months, it grows stronger than regular concrete as it ages, like the Pantheon.

University labs have tested concretes made entirely with fly ash and found that some actually outperform the standard variety. More than 15 years ago, researchers at Montana State University used concrete made with 100 percent fly ash in the floors and walls of a credit union and a transportation research center. But performance depends greatly on the chemical makeup of the ash, which varies from one coal plant to the next, and on following a tricky recipe. The decommissioning of coal-fired plants has also been making fresh fly ash scarcer and more expensive.

At Sublime Systems’ pilot plant in Massachusetts, the company is using electrochemistry instead of heat to produce lime silicate cements that can replace Portland cement.Tony Luong

That has spurred new methods to treat and use fly ash that’s been buried in landfills or dumped into ponds. Such industrial burial grounds hold enough fly ash to make concrete for decades, even after every coal plant shuts down. Utah-based Eco Material Technologies is now producing cements that include both fresh and recovered fly ash as ingredients. The company claims it can replace up to 60 percent of the Portland cement in concrete—and that a new variety, suitable for 3D printing, can substitute entirely for Portland cement.

Hive 3D Builders, a Houston-based startup, has been feeding that low-emissions concrete into robots that are printing houses in several Texas developments. “We are 100 percent Portland cement–free,” says Timothy Lankau, Hive 3D’s CEO. “We want our homes to last 1,000 years.”

Sublime Systems, a startup spun out of MIT by battery scientists, uses electrochemistry rather than heat to make low-carbon cement from rocks that don’t contain carbon. Similar to a battery, Sublime’s process uses a voltage between an electrode and a cathode to create a pH gradient that isolates silicates and reactive calcium, in the form of lime (CaO). The company mixes those ingredients together to make a cement with no fugitive carbon, no kilns or furnaces, and binding power comparable to that of Portland cement. With the help of $87 million from the U.S. Department of Energy, Sublime is building a plant in Holyoke, Mass., that will be powered almost entirely by hydroelectricity. Recently the company was tapped to provide concrete for a major offshore wind farm planned off the coast of Martha’s Vineyard.

Software takes on the hard problem of concrete

It is unlikely that any one innovation will allow the cement industry to hit its target of carbon neutrality before 2050. New technologies take time to mature, scale up, and become cost-competitive. In the meantime, says Philippe Block, a structural engineer at ETH Zurich, smart engineering can reduce carbon emissions through the leaner use of materials.

His research group has developed digital design tools that make clever use of geometry to maximize the strength of concrete structures while minimizing their mass. The team’s designs start with the soaring architectural elements of ancient temples, cathedrals, and mosques—in particular, vaults and arches—which they miniaturize and flatten and then 3D print or mold inside concrete floors and ceilings. The lightweight slabs, suitable for the upper stories of apartment and office buildings, use much less concrete and steel reinforcement and have a CO₂ footprint that’s reduced by 80 percent.

There’s hidden magic in such lean design. In multistory buildings, much of the mass of concrete is needed just to hold the weight of the material above it. The carbon savings of Block’s lighter slabs thus compound, because the size, cost, and emissions of a building’s conventional-concrete elements are slashed.

Vaulted, a Swiss startup, uses digital design tools to minimize the concrete in floors and ceilings, cutting their CO₂ footprint by 80 percent.Vaulted

In Dübendorf, Switzerland, a wildly shaped experimental building has floors, roofs, and ceilings created by Block’s structural system. Vaulted, a startup spun out of ETH, is engineering and fabricating the lighter floors of a 10-story office building under construction in Zug, Switzerland.

That country has also been a leader in smart ways to recycle and reuse concrete, rather than simply landfilling demolition rubble. This is easier said than done—concrete is tough stuff, riddled with rebar. But there’s an economic incentive: Raw materials such as sand and limestone are becoming scarcer and more costly. Some jurisdictions in Europe now require that new buildings be made from recycled and reused materials. The new addition of the Kunsthaus Zürich museum, a showcase of exquisite Modernist architecture, uses recycled material for all but 2 percent of its concrete.

As new policies goose demand for recycled materials and threaten to restrict future use of Portland cement across Europe, Holcim has begun building recycling plants that can reclaim cement clinker from old concrete. It recently turned the demolition rubble from some 1960s apartment buildings outside Paris into part of a 220-unit housing complex—touted as the first building made from 100 percent recycled concrete. The company says it plans to build concrete recycling centers in every major metro area in Europe and, by 2030, to include 30 percent recycled material in all of its cement.

Further innovations in low-carbon concrete are certain to come, particularly as the powers of machine learning are applied to the problem. Over the past decade, the number of research papers reporting on computational tools to explore the vast space of possible concrete mixes has grown exponentially. Much as AI is being used to accelerate drug discovery, the tools learn from huge databases of proven cement mixes and then apply their inferences to evaluate untested mixes.

Researchers from the University of Illinois and Chicago-based Ozinga, one of the largest private concrete producers in the United States, recently worked with Meta to feed 1,030 known concrete mixes into an AI. The project yielded a novel mix that will be used for sections of a data-center complex in DeKalb, Ill. The AI-derived concrete has a carbon footprint 40 percent lower than the conventional concrete used on the rest of the site. Ryan Cialdella, Ozinga’s vice president of innovation, smiles as he notes the virtuous circle: AI systems that live in data centers can now help cut emissions from the concrete that houses them.

A sustainable foundation for the information age

Cheap, durable, and abundant yet unsustainable, concrete made with Portland cement has been one of modern technology’s Faustian bargains. The built world is on track to double in floor space by 2060, adding 230,000 km ², or more than half the area of California. Much of that will house the 2 billion more people we are likely to add to our numbers. As global transportation, telecom, energy, and computing networks grow, their new appendages will rest upon concrete. But if concrete doesn’t change, we will perversely be forced to produce even more concrete to protect ourselves from the coming climate chaos, with its rising seas, fires, and extreme weather.

The AI-driven boom in data centers is a strange bargain of its own. In the future, AI may help us live even more prosperously, or it may undermine our freedoms, civilities, employment opportunities, and environment. But solutions to the bad climate bargain that AI’s data centers foist on the planet are at hand, if there’s a will to deploy them. Hyperscalers and governments are among the few organizations with the clout to rapidly change what kinds of cement and concrete the world uses, and how those are made. With a pivot to sustainability, concrete’s unique scale makes it one of the few materials that could do most to protect the world’s natural systems. We can’t live without concrete—but with some ambitious reinvention, we can thrive with it.

This article was updated on 04 November 2024.

Just before this special issue on invention went to press, I got a message from IEEE senior member and patent attorney George Macdonald. Nearly two decades after I first reported on Corliss Orville “Cob” Burandt’s struggle with the U.S. Patent and Trademark Office, the 77-year-old inventor’s patent case was being revived.

From 1981 to 1990, Burandt had received a dozen U.S. patents for improvements to automotive engines, starting with his 1990 patent for variable valve-timing technology (U.S. Patent No. 4,961,406A). But he failed to convince any automakers to license his technology. What’s worse, he claims, some of the world’s major carmakers now use his inventions in their hybrid engines.

Shortly after reading my piece in 2005, Macdonald stepped forward to represent Burandt. By then, the inventor had already lost his patents because he hadn’t paid the US $40,000 in maintenance fees to keep them active.

Macdonald filed a petition to pay the maintenance fees late and another to revive a related child case. The maintenance fee petition was denied in 2006. While the petition to revive was still pending, Macdonald passed the maintenance fee baton to Hunton Andrews Kurth (HAK), which took the case pro bono. HAK attorneys argued that the USPTO should reinstate the 1990 parent patent.

The timing was crucial: If the parent patent was reinstated before 2008, Burandt would have had the opportunity to compel infringing corporations to pay him licensing fees. Unfortunately, for reasons that remain unclear, the patent office tried to paper Burandt’s legal team to death, Macdonald says. HAK could go no further in the maintenance-fee case after the U.S. Supreme Court declined to hear it in 2009.

Then, in 2010, the USPTO belatedly revived Burandt’s child continuation application. A continuation application lets an inventor add claims to their original patent application while maintaining the earlier filing date—1988 in this case.

However, this revival came with its own set of challenges. Macdonald was informed in 2011 that the patent examiner would issue the patent but later discovered that the application was placed into a then-secret program called the Sensitive Application Warning System (SAWS) instead. While touted as a way to quash applications for things like perpetual-motion machines, the SAWS process effectively slowed action on Burandt’s case.

After several more years of motions and rulings, Macdonald met IEEE Member Edward Pennington, who agreed to represent Burandt. Earlier this year, Pennington filed a complaint in the Eastern District of Virginia seeking the issuance of Burandt’s patent on the grounds that it was wrongfully denied.

As of this writing, Burandt still hasn’t seen a dime from his inventions. He subsists on his social security benefits. And while his case raises important questions about fairness, transparency, and the rights of individual inventors, Pennington says his client isn’t interested in becoming a poster boy for poor inventors.

“We’re not out to change policy at the patent office or to give Mr. Burandt a framed copy of the patent to say, ‘Look at me, I’m an inventor,’ ” says Pennington. “This is just to say, ‘Here’s a guy that would like to benefit from his idea.’ It just so happens that he’s pretty much in need. And even the slightest royalty would go a long ways for the guy.”

Over the Northern Hemisphere's summer, the world's temperatures hovered near 1.5° C above pre-industrial temperatures, and the catastrophic weather events that ensued provided a preview of what might be expected to be the new normal before mid-century. And the warming won't stop there; our current emissions trajectory is such that we will double that temperature increase by the time the century is out and continue beyond its end.

This frightening trajectory and its results have led many people to argue that some form of geoengineering is necessary. If we know the effects of that much warming will be catastrophic, why not try canceling some of it out? Unfortunately, the list of "why nots" includes the fact that we don't know how well some of these techniques work or fully understand their unintended consequences. This means more research is required before we put them into practice.

But how do we do that research if there's the risk of unintended consequences? To help guide the process, the American Geophysical Union (AGU) has just released guidelines for ensuring that geoengineering research is conducted ethically.

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On Thursday, the United Nations' Environmental Programme (UNEP) released a report on what it terms the "emissions gap"—the difference between where we're heading and where we'd need to be to achieve the goals set out in the Paris Agreement. It makes for some pretty grim reading. Given last year's greenhouse gas emissions, we can afford fewer than four similar years before we would exceed the total emissions compatible with limiting the planet's warming to 1.5° C above pre-industrial conditions. Following existing policies out to the turn of the century would leave us facing over 3° C of warming.

The report ascribes this situation to two distinct emissions gaps: between the goals of the Paris Agreement and what countries have pledged to do and between their pledges and the policies they've actually put in place. There are some reasons to think that rapid progress could be made—the six largest greenhouse gas emitters accounted for nearly two-thirds of the global emissions, so it wouldn't take many policy changes to make a big difference. And the report suggests increased deployment of wind and solar could handle over a quarter of the needed emissions reductions.

But so far, progress has been far too limited to cut into global emissions.

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A company making fire-suppressing battery materials just got a $670.6 million loan commitment from the US Department of Energy.

Aspen Aerogels makes insulating materials that can be layered inside an EV’s battery to prevent or slow heat and fires from spreading within the pack. The company is building a new factory in Georgia to produce its materials, and the DOE’s Loan Programs Office will provide the massive loan to help it finish building the plant. 

As more EVs hit the roads, concern is growing about the relatively rare but dangerous problem of battery fires. While gas-powered cars catch fire at higher rates, battery fires can be harder to put out and are at greater risk of reigniting, creating dangerous situations for drivers and first responders. Materials like Aspen Aerogels’ thermal barriers can help improve battery safety.

“I think the goal is to really make sure that they’re helping to achieve critical battery safety goals that we all share,” says Jigar Shah, director of the Loan Programs Office.

Automakers including General Motors, Toyota, and Audi already buy Aspen Aerogels materials to use in their vehicles. If the new factory starts as planned and ramps to full capacity, it could supply material for over two million EVs annually.

When a lithium-ion battery is damaged or short-circuits, it can go into a process called thermal runaway, a feedback loop of heat and chemical reactions that can lead to a fire or explosion. Electric vehicles’ battery packs are made up of many small battery cells wired together—so there’s a risk that a problem in one cell can spread to the rest of the pack.

The thermal barriers the company makes can be tucked between cells, creating an obstacle that can suppress that spread. Depending on how an automaker uses the materials, aerogel insulation can at a minimum slow down the propagation of thermal runaway, giving a driver enough time to get out of the car. Or automakers can use the materials to design batteries that can confine a bad cell or a group of cells, so “instead of having a car-melting fire, you have a more isolated event,” Young says. 

Aerogels are very good at insulating to maintain hot or cold temperatures, since they’re mostly made of microscopic pockets of air. Aspen won research grants from NASA to explore the use of its materials for spacesuits and other applications in the early 2000s, and it has sold materials for equipment in facilities including oil refineries and liquefied-natural-gas terminals in the decades since, says Don Young, the company’s CEO.

The company began using its aerogels in battery materials in 2021. The start was a partnership with General Motors, Young says—the automaker was having issues with Chevy Bolt batteries catching fire at the time. 

While aerogels can help with the severity of battery fires, they can’t entirely prevent thermal runaway events. “Currently, we are not aware of any commercial technology that reliably prevents thermal runaway,” says In Taek Song, a researcher at LG Chem and part of a team that recently published research on safety devices for lithium-ion batteries, via email. Lithium-ion batteries contain flammable materials and can store a lot of energy. 

Automakers and battery manufacturers already put some measures in place to lower the risk of thermal runaway, including battery management systems that can detect and control battery conditions to prevent fires before they occur. Thermal insulation materials—including those made with aerogels—are part of the growing arsenal that can limit the damage if thermal runaway does occur.

One potential drawback to those materials is that they add bulk to a battery, which reduces energy density—the amount of energy that a battery can store in a certain volume or weight. Higher energy density translates to longer range for an EV, a crucial selling point for many drivers. The benefit of aerogels is that they’re super-light, since they’re mostly air—so they don’t limit energy density as much as other materials might. 

Aspen’s thermal barriers are typically between one and four millimeters thick and can be stacked between cells. Depending on the automaker and vehicle in question, the cost to incorporate it in an EV runs between $300 and $1,000, Young says. 

COURTESY OF ASPEN AEROGEL

The market is ramping up quickly. When the company began selling its battery materials in 2021, it did roughly $7 million in sales. In 2023 it had reached $110 million, and that’s on track to more than double again in 2024, Young says. 

Aspen Aerogels currently makes materials for EV batteries at its factory in Rhode Island, which also makes materials for other businesses, including the oil and gas industry. “We’re just busting at the seams of that plant,” Young says. The DOE loan will support construction of a new facility in Georgia, which will be entirely dedicated to making material for EV batteries. The plan is to have that facility running by early 2027, Young says. 

“This loan is to really get them at scale for their first commercial facility in Georgia,” Shah says. The company will need to meet certain financial and technical requirements to finalize the funding. 

“This loan is critically important to us, to help us with the completion of that project,” Young says. 

Correction: A caption has been updated to correctly identify the material pictured as a thermal barrier.

On July 21, 2024, temperatures soared in many parts of the world, breaking the record for the hottest day ever recorded on the planet.

The following day—July 22—the record was broken again.

But even as the heat index rises each summer, the people working outdoors to pick fruits, vegetables, and flowers for American tables keep laboring in the sun.

The consequences can be severe, leading to illnesses such as heat exhaustion or heatstroke. Body temperature can rise so high that farmworkers are “essentially … working with fevers,” says Roxana Chicas, an assistant professor at Emory University’s School of Nursing. In one study by Chicas’s research team, most farmworkers tested were chronically dehydrated, even when they drank fluids throughout the day. And many showed signs of developing acute kidney injury after just one workday.

Chicas is part of an Emory research program that has been investigating farmworker health since 2009. Emphasizing collaboration between researchers and community members, the team has spent years working with farmworkers to collect data on kidney function, the risk of heat illness, and the effectiveness of cooling interventions.

The team is now developing an innovative sensor that tracks multiple vital signs with a goal of anticipating that a worker will develop heat illness and issuing an alert.

If widely adopted and consistently used, it could represent a way to make workers safer on farms even without significant heat protections. Right now, with limited rules on such protections, workers are often responsible for their own safety. “The United States is primarily focused on educating workers on drinking water [and] the symptoms of heat-related illness,” says Chicas, who leads a field team that tested the sensor in Florida last summer.

The sensor project, a collaboration between Emory and engineers at the Georgia Institute of Technology, got its start in 2022, when the team was awarded a $2.46 million, four-year grant from the National Institute of Environmental Health Sciences. The sensor is now able to continuously measure skin temperature, heart rate, and physical activity. A soft device meant to be worn on the user’s chest, it was designed with farmworkers’ input; it’s not uncomfortable to wear for several hours in the heat, it won’t fall off because of sweat, and it doesn’t interfere with the physical movement necessary to do agricultural work.

To translate the sensor data into useful warnings, the team is now working on building a model to predict the risk of heat-related injury.

Chicas understands what drives migrant workers to the United States to labor on farms in the hot sun. When she was a child, her own family immigrated to the US to seek work, settling in Georgia. She remembers listening to stories from farmworker family members and friends about how hot it was in the fields—about how they would leave their shifts with headaches.

But because farmworkers are largely from Latin America (63% were born in Mexico) and nearly half are undocumented, “it’s difficult for [them] to speak up about [their] working conditions,” says Chicas. Workers are usually careful not to draw attention that “may jeopardize their livelihoods.”

They’re more likely to do so if they’re backed up by an organization like the Farmworker Association of Florida, which organizes agricultural workers in the state. FWAF has collaborated with the Emory program for more than a decade, recruiting farmworkers to participate in the studies and help guide them. 

There’s “a lot of trust” between those involved in the program, says Ernesto Ruiz, research coordinator at FWAF. Ruiz, who participated in data collection in Florida this past year, says there was a waiting list to take part in the project because there was so much interest—even though participants had to arrive at the break of dawn before a long day of work.

“We need to be able to document empirically, with uncontroversial evidence, the brutal working conditions that farmworking communities face and the toll it takes on their bodies.”

Ernesto Ruiz, research coordinator, Farmworker Association of Florida

Participants had their vital signs screened in support of the sensor research. They also learned about their blood glucose levels, cholesterol, triglycerides, HDL, and LDL. These readings, Ruiz says, “[don’t] serve any purpose from the standpoint of a predictive variable for heat-related injury.” But community members requested the additional health screenings because farmworkers have little to no access to health care. If health issues are found during the study, FWAF will work to connect workers to health-care providers or free or low-cost clinics.

“Community-based participatory research can’t just be extractive, eliciting data and narratives,” Ruiz says. “It has to give something in return.”

Work on technology to measure heat stress in farmworkers could feed back into policy development. “We need to be able to document empirically, with uncontroversial evidence, the brutal working conditions that farmworking communities face and the toll it takes on their bodies,” Ruiz says.

Though the Biden administration has proposed regulations, there are currently no federal standards in place to protect workers from extreme heat. (Only five states have their own heat standards.) Areas interested in adding protections can face headwinds. In Florida, for example, after Miami-Dade County proposed heat protection standards for outdoor workers, the state passed legislation preventing localities from issuing their own heat rules, pointing to the impact such standards could have on employers.

Meanwhile, temperatures continue to rise. With workers “constantly, chronically” exposed to heat in an environment without protective standards, says Chicas, the sensor could offer its own form of protection. 

Kalena Thomhave is a freelance journalist based in Pittsburgh.

The first time the rains failed, the farmers of Kanaani were prepared for it. It was April of 2021, and as climate change had made the weather increasingly erratic, families in the eastern Kenyan village had grown used to saving food from previous harvests. But as another wet season passed with barely any rain, and then another, the community of small homesteads, just off the main road linking Nairobi to the coast of the Indian Ocean, found itself in a full-fledged hunger crisis. 

By the end of 2022, Danson Mutua, a longtime Kanaani resident, counted himself lucky that his farm still had pockets of green: Over the years, he’d gradually replaced much of his maize, the staple crop in Kenya and several other parts of Africa, with more drought-resistant crops. He’d planted sorghum, a tall grass capped with tufts of seeds that look like arrowheads, as well as protein-rich legumes like pigeon peas and green gram, which don’t require any chemical fertilizers and are also prized for fixing nitrogen in soils. Many of his neighbors’ fields were completely parched. Cows, with little to eat themselves, had stopped producing milk; some had started dying. While it was still possible to buy grain at the local market, prices had spiked, and few people had the cash to pay for it. 

Mutua, a father of two, began using his bedroom to secure the little he’d managed to harvest. “If I left it out, it would have disappeared,” he told me from his home in May, 14 months after the rains had finally returned and allowed Kanaani’s farmers to begin recovering. “People will do anything to get food when they’re starving.”

The food insecurity facing Mutua and his neighbors is hardly unique. In 2023, according to the United Nations’ Food and Agriculture Organization, or FAO, an estimated 733 million people around the world were “undernourished,” meaning they lacked sufficient food to “maintain a normal, active, and healthy life.” After falling steadily for decades, the prevalence of global hunger is now on the rise—nowhere more so than in sub-Saharan Africa, where conflicts, economic fallout from the covid-19 pandemic, and extreme weather events linked to climate change pushed the share of the population considered undernourished from 18% in 2015 to 23% in 2023. The FAO estimates that 63% of people in the region are “food insecure”—not necessarily undernourished but unable to consistently eat filling, nutritious meals.

In Africa, like anywhere, hunger is driven by many interwoven factors, not all of which are a consequence of farming practices. Increasingly, though, policymakers on the continent are casting a critical eye toward the types of crops in farmers’ plots, especially the globally dominant and climate-vulnerable grains like rice, wheat, and above all, maize. Africa’s indigenous crops are often more nutritious and better suited to the hot and dry conditions that are becoming more prevalent, yet many have been neglected by science, which means they tend to be more vulnerable to diseases and pests and yield well below their theoretical potential. Some refer to them as “orphan crops” because of this. 

Efforts to develop new varieties of many of these crops, by breeding for desired traits, have been in the works for decades—through state-backed institutions, a continent-wide research consortium, and underfunded scientists’ tinkering with hand-pollinated crosses. Now those endeavors have gotten a major boost: In 2023, the US Department of State, in partnership with the African Union, the FAO, and several global agriculture institutions, launched the Vision for Adapted Crops and Soils, or VACS, a new Africa-focused initiative that seeks to accelerate research and development for traditional crops and help revive the region’s long-­depleted soils. VACS, which had received funding pledges worth $200 million as of August, marks an important turning point, its proponents say—not only because it’s pumping an unprecedented flow of money into foods that have long been disregarded but because it’s being driven by the US government, which has often promoted farming policies around the world that have helped entrench maize and other food commodities at the expense of local crop diversity.

It may be too soon to call VACS a true paradigm shift: Maize is likely to remain central to many governments’ farming policies, and the coordinated crop R&D the program seeks to hasten is only getting started. Many of the crops it aims to promote could be difficult to integrate into commercial supply chains and market to growing urban populations, which may be hesitant to start eating like their ancestors. Some worry that crops farmed without synthetic fertilizers and pesticides today will be “improved” in a way that makes farmers more dependent on these chemicals—in turn, raising farm expenses and eroding soil fertility in the long run. Yet for many of the policymakers, scientists, and farmers who’ve been championing crop diversity for decades, this high-level attention is welcome and long overdue.

“One of the things our community has always cried for is how to raise the profile of these crops and get them on the global agenda,” says Tafadzwa Mabhaudhi, a longtime advocate of traditional crops and a professor of climate change, food systems, and health at the London School of Hygiene and Tropical Medicine, who comes from Zimbabwe.

Now the question is whether researchers, governments, and farmers like Mutua can work together in a way that gets these crops onto plates and provides Africans from all walks of life with the energy and nutrition that they need to thrive, whatever climate change throws their way.

A New World addiction

Africa’s love affair with maize, which was first domesticated several thousand years ago in central Mexico, dates to a period known as the Columbian exchange, when the trans-Atlantic flow of plants, animals, metals, diseases, and people—especially enslaved Africans—dramatically reshaped the world economy. The new crop, which arrived in Africa sometime after 1500 along with other New World foods like beans, potatoes, and cassava, was tastier and required less labor than indigenous cereals like millet and sorghum, and under the right conditions it could yield significantly more calories. It quickly spread across the continent, though it didn’t begin to dominate until European powers carved up most of Africa into colonies in the late 19th century. Its uptake was greatest in southern Africa and Kenya, which both had large numbers of white settlers. These predominantly British farmers, tilling land that had often been commandeered from Africans, began adopting new maize varieties that were higher yielding and more suitable for mechanized milling—albeit less nutritious—than both native grains and the types of maize that had been farmed locally since the 16th century. 

“People plant maize, harvest nothing, and still plant maize the next season. It’s difficult to change that mindset.”

Florence Wambugu, CEO, Africa Harvest

Eager to participate in the new market economy, African farmers followed suit; when hybrid maize varieties arrived in the 1960s, promising even higher yields, the binge only accelerated. By 1990, maize accounted for more than half of all calories consumed in Malawi and Zambia and at least 20% of calories eaten in a dozen other African countries. Today, it remains omnipresent—as a flour boiled into a sticky paste; as kernels jumbled with beans, tomatoes, and a little salt; or as fermented dumplings steamed and served inside the husk. Florence Wambugu, CEO of Africa Harvest, a Kenyan organization that helps farmers adopt maize alternatives, says the crop has such cultural significance that many insist on cultivating it even where it often fails. “People plant maize, harvest nothing, and still plant maize the next season,” she says. “It’s difficult to change that mindset.”

Maize and Africa have never been a perfect match. The plant is notoriously picky, requiring nutrient-rich soils and plentiful water at specific moments. Many of Africa’s soils are naturally deficient in key elements like nitrogen and phosphorus. Over time, the fertilizers needed to support hybrid varieties, often subsidized by governments, depleted soils even further. Large portions of Africa’s inhabited areas are also dry or semi-arid, and 80% of farms south of the Sahara are occupied by smallholders, who work plots of 10 hectares or less. On these farms, irrigation can be spatially impractical and often does not make economic sense. 

It would be a stretch to blame Africa’s maize addiction for its most devastating hunger crises. Research by Alex de Waal, an expert in humanitarian disasters at Tufts University, has found that more than three-quarters of global famine deaths between 1870 and 2010 occurred in the context of “conflict or political repression.” That description certainly applies to today’s worst hunger crisis, in Sudan, a country being ripped apart by rival military governments. As of September, according to the UN, more than 8.5 million people in the country were facing “emergency levels of hunger,” and 755,000 were facing conditions deemed “catastrophic.”

ADAM DETOUR

For most African farmers, though, weather extremes pose a greater risk than conflict. The two-year drought that affected Mutua, for example, has been linked to a narrowing of the cloud belt that straddles the equator, as well as the tendency of land to lose moisture faster in higher temperatures. According to one 2023 study, by a global coalition of meteorologists, these climatic changes made that drought—which contributed to a 22% drop in Kenya’s national maize output and forced a million people from their homes across eastern Africa—100 times more likely. The UN’s Intergovernmental Panel on Climate Change expects yields of maize, wheat, and rice in tropical regions to fall by 5%, on average, for every degree Celsius that the planet heats up. Eastern Africa could be especially hard hit. A rise in global temperatures of 1.5 degrees above preindustrial levels, which scientists believe is likely to occur sometime in the 2030s, is projected to cause maize yields there to drop by roughly one-third from where they stood in 2005.  

Food demand continues to rise: Sub-Saharan Africa’s population, 1.2 billion now, is expected to surpass 2 billion by 2050.

Food demand, at the same time, will continue to rise: Sub-Saharan Africa’s population, 1.2 billion now, is expected to surpass 2 billion by 2050, and roughly half of those new people will be born and come of age in cities. Many will grow up on Westernized diets: Young, middle-class residents of Nairobi today are more likely to meet friends for burgers than to eat local dishes like nyama choma, roasted meat typically washed down with bottles of Tusker lager. KFC, seen by many as a status symbol, has franchises in a dozen Kenyan towns and cities; those looking to splurge can dine on sushi crafted from seafood flown in specially from Tokyo. Most, though, get by on simple foods like ugali, a maize porridge often accompanied by collard greens or kale. Although some urban residents consume maize grown on family farms “upcountry,” most of them buy it; when domestic harvests underperform, imports rise and prices spike, and more people go hungry. 

A solution from science?

The push to revive Africa’s indigenous crops is a matter of nutrition as well. An overreliance on maize and other starches is a big reason that nearly a third of children under five in sub-Saharan Africa are stunted—a condition that can affect cognition and immune system functioning for life. Many traditional foods are nutrient dense and have potential to combat key dietary deficiencies, says Enoch Achigan-Dako, a professor of genetics and plant breeding at the University of Abomey-Calavi in Benin. He cites egusi as a prime example. The melon seed, used in a popular West African soup, is rich in protein and the B vitamins the body needs to convert food into energy; it is already a lifeline in many places where milk is not widely available. Breeding new varieties with shorter growth cycles, he says, could make the plant more viable in drier areas. Achigan-Dako also believes that many orphan crops hold untapped commercial potential that could help farmers combat hunger indirectly. 

Increasingly, institutions are embracing similar views. In 2013, the 55-­member-state African Union launched the African Orphan Crops Consortium, or AOCC—a collaboration with CGIAR, a global coalition of 15 nonprofit food research institutions, the University of California, Davis, and other partners. The AOCC has since trained more than 150 scientists from 28 African countries in plant breeding techniques through 18-month courses held in Nairobi. It’s also worked to sequence the genomes of 101 understudied crops, in part to facilitate the use of genomic selection. This technique involves correlating observed traits, like drought or pest resistance, with plant DNA, which helps breeders make better-­informed crosses and develop new varieties faster. The consortium launched another course last year to train African scientists in the popular gene-editing technique CRISPR, which enables the tweaking of plant DNA directly. While regulatory and licensing hurdles remain, Leena Tripathi, a molecular biologist at CGIAR’s International Institute of Tropical Agriculture (IITA) and a CRISPR course instructor, believes gene-editing tools could eventually play a big role in accelerating breeding efforts for orphan crops. Most exciting, she says, is the promise of mimicking genes for disease resistance that are found in wild plants but not in cultivated varieties available for crossing.   

For many orphan crops, old-­fashioned breeding techniques also hold big promise. Mathews Dida, a professor of plant genetics and breeding at Kenya’s Maseno University and an alumnus of the AOCC’s course in Nairobi, has focused much of his career on the iron-rich grain finger millet. He believes yields could more than double if breeders incorporated a semi-dwarf gene—a technique first used with wheat and rice in the 1960s. That would shorten the plants so that they don’t bend and break when supplied with nitrogen-based fertilizer. Yet money for such projects, which largely comes from foreign grants, is often tight. “The effort we’re able to put in is very erratic,” he says.

VACS, the new US government initiative, was envisioned in part to help plug these sorts of gaps. Its move to champion traditional crops marks a significant pivot. The United States was a key backer of the Green Revolution that helped consolidate the global dominance of rice, wheat, and maize during the 1960s and 1970s. And in recent decades its aid dollars have tended to support programs in Africa that also emphasize the chemical-­intensive farming of maize and other commercial staples. 

Change, though, was afoot: In 2021, with hunger on the rise, the African Union explicitly called for “intentional investments towards increased productivity and production in traditional and indigenous crops.” It found a sympathetic ear in Cary Fowler, a longtime biodiversity advocate who was appointed US special envoy for global food security by President Joe Biden in 2022. The 74-year-old Tennessean was a co-recipient of this year’s World Food Prize, agriculture’s equivalent of the Nobel, for his role in establishing the Svalbard Global Seed Vault, a facility in the Norwegian Arctic that holds copies of more than 1.3 million seed samples from around the world. Fowler has argued for decades that the loss of crop diversity wrought by the global expansion of large-scale farming risks fueling future hunger crises.

VACS, which complements the United States’ existing food security initiative, Feed the Future, began by working with the AOCC and other experts to develop an initial list of underutilized crops that were climate resilient and had the greatest potential to boost nutrition in Africa. It pared that list down to a group of 20 “opportunity crops” and commissioned models that assessed their future productivity under different climate-change scenarios. The models predicted net yield gains for many: Carbon dioxide, including that released by burning fossil fuels, is the key input in plant photosynthesis, and in some cases the “fertilization effect” of higher atmospheric CO₂ can more than nullify the harmful impact of hotter temperatures. 

According to Fowler’s deputy, Anna Nelson, VACS will now operate as a “broad coalition,” with funds channeled through four core implementing partners. One of them, CGIAR, is spearheading R&D on an initial seven of those 20 crops—pigeon peas, Bambara groundnuts, taro, sesame, finger millet, okra, and amaranth—through partnerships with a range of research institutions and scientists. (Mabhaudhi, Achigan-Dako, and Tripathi are all involved in some capacity.) The FAO is leading an initiative that seeks to drive improvements in soil fertility, in part through tools that help farmers decide where and what to plant on the basis of soil characteristics. While Africa remains VACS’s central focus, activities have also launched or are being planned in Guatemala, Honduras, and the Pacific Community, a bloc of 22 Pacific island states and territories. The idea, Nelson tells me, is that VACS will continue to evolve as a “movement” that isn’t necessarily tied to US funding—or to the priorities of the next occupant of the White House. “The US is playing a convening and accelerating role,” she says. But the movement, she adds, is “globally owned.”

Making farm-to-table work

In some ways, the VACS concept is a unifying one. There’s long been a big and often rancorous divide between those who believe Africa needs more innovation-­driven Green Revolution–style agriculture and those promoting ecological approaches, who insist that chemically intensive commercial crops aren’t fit for smallholders. In its focus on seed science as well as crop diversity and soil, VACS has something to offer both. Still, the degree to which the movement can change the direction of Africa’s food production remains an open question. VACS’s initial funding—roughly $150 million pledged by the US and $50 million pledged by other governments as of August—is more than has ever been earmarked for traditional crops and soils at a single moment. The AOCC, by comparison, spent $6.5 million on its plant breeding academy over a decade; as of 2023, its alumni had received a total of $175 million, largely from external grants, to finance crop improvement. Yet enabling orphan crops to reach their full potential, says Allen Van Deynze, the AOCC’s scientific director, who also heads the Seed Biotechnology Center at the University of California, Davis, would require an even bigger scale-up: $1 million per year, ideally, for every type of crop being prioritized in every country, or between $500 million and $1 billion per year across the continent.

“If there are shortages of maize, there will be demonstrations. But nobody’s going to demonstrate if there’s not enough millet, sorghum, or sweet potato.”

Florence Wambugu, CEO, Africa Harvest

Despite the African Union’s support, it remains to be seen if VACS will galvanize African governments to chip in more for crop development themselves. In Kenya, the state-run Agricultural & Livestock Research Organization, or KALRO, has R&D programs for crops such as pigeon peas, green gram, sorghum, and teff. Nonetheless, Wambugu and others say the overall government commitment to traditional crops is tepid—in part because they don’t have a big impact on politics. “If there are shortages of maize, there will be demonstrations,” she says. “But nobody’s going to demonstrate if there’s not enough millet, sorghum, or sweet potato.”

Others express concern that some participants in the VACS movement, including global institutions and private companies, could co-opt long-standing efforts by locals to support traditional crops. Sabrina Masinjila, research and advocacy officer at the African Center for Biodiversity, a Johannesburg-based organization that promotes ecological farming practices and is critical of corporate involvement in Africa’s food systems, sees red flags in VACS’s partnerships with several Western companies. Most concerning, she says, is the support of Bayer, the German biotech conglomerate, for the IITA’s work developing climate-­resilient varieties of banana. In 2018 Bayer purchased Monsanto, which had become a global agrochemical giant through the sale of glyphosate, a weed killer the World Health Organization calls “probably carcinogenic,” along with seeds genetically modified to resist it. Monsanto had also long attracted scrutiny for aggressively pursuing claims of seed patent violations against farmers. Masinjila, a Tanzanian, fears that VACS could open the door to multinational companies’ use of African crops’ genetic sequences for their own private interests or to develop varieties that demand application of expensive, environmentally damaging pesticides and fertilizers.

According to Nelson, no VACS-related US funding will go to crop development that results in any private-sector patents. Seeds developed through CGIAR, VACS’s primary crop R&D partner, are considered to be public goods and are generally made available to governments, researchers, and farmers free of charge. Nonetheless, Nelson does not rule out the possibility that some improved varieties might require costlier, non-organic farming methods. “At its core, VACS is about making more options available to farmers,” she says.

While most indigenous-crop advocates I’ve spoken to are excited about VACS’s potential, several cite other likely bottlenecks, including challenges in getting improved varieties to farmers. A 2023 study by Benson Nyongesa, a professor of plant genetics at the University of Eldoret in Kenya, found that 33% of registered varieties of sorghum and 47% of registered varieties of finger millet had not made it into the fields of farmers; instead, he says, they remained “sitting on the shelves of the institutions that developed them.” The problem represents a market failure: Most traditional crops are self- or open-­pollinated, which means farmers can save a portion of their harvest to plant as seeds the following year instead of buying new ones. Seed companies, he and others say, are out to make a profit and are generally not interested in commercializing them.

Farmers can access seeds in other ways, sometimes with the help of grassroots organizations. Wambugu’s Africa Harvest, which receives funding from the Mastercard Foundation, provides a “starter pack” of seeds for drought-­tolerant crops like sorghum, groundnuts, pigeon peas, and green gram. It also helps its beneficiaries navigate another common challenge: finding markets for their produce. Most smallholders consume a portion of the crops they grow, but they also need cash, and commercial demand isn’t always forthcoming. Part of the reason, says Pamela Muyeshi, owner of Amaica, a Nairobi restaurant specializing in traditional Kenyan fare, is that Kenyans often consider indigenous foods to be “primitive.” This is especially true for those in urban areas who face food insecurity and could benefit from the nutrients these foods offer but often feel pressure to appear modern. Lacking economies of scale, many of these foods remain expensive. To the extent they’re catching on, she says, it’s mainly among the affluent.

ADAM DETOUR

Similar “social acceptability” barriers will need to be overcome in South Africa, says Peter Johnston, a climate scientist who specializes in agricultural adaptation at the University of Cape Town. Johnston believes traditional crops have an important role to play in Africa’s climate resilience efforts, but he notes that no single crop is fully immune to the extreme droughts, floods, and heat waves that have become more frequent and more unpredictable. Crop diversification strategies, he says, will work best if paired with “anticipatory action”—pre-agreed and pre-financed responses, like the distribution of food aid or cash, when certain weather-related thresholds are breached.

Mutua, for his part, is a testament that better crop varieties, coupled with a little foresight, can go a long way in the face of crisis. When the drought hit in 2021, his maize didn’t stand a chance. Yields of pigeon peas and cowpeas were well below average. Birds, notorious for feasting on sorghum, were especially ravenous. The savior turned out to be green gram, better known in Kenya by its Swahili name, ndengu. Although native to India, the crop is well suited to eastern Kenya’s sandy soils and semi-arid climate, and varieties bred by KALRO to be larger and faster maturing have helped its yields improve over time. In good years, Mutua sells much of his harvest, but after the first season with barely any rain, he hung onto it; soon, out of necessity, ndengu became the fixture of his family’s diet. On my visit to his farm, he pointed it out with particular reverence: a low-lying plant with slender green pods that radiate like spokes of a bicycle wheel. The crop, Mutua told me, has become so vital to this area that some people consider it their “gold.”

If the movement to revive “forgotten” crops lives up to its promise, other climate-­stressed corners of Africa might soon discover their gold equivalent as well.

Jonathan W. Rosen is a journalist who writes about Africa. Evans Kathimbu assisted his reporting from Kenya.

On a languid, damp July morning, I meet weed scientist Aaron Hager outside the old Agronomy Seed House at the University of Illinois’ South Farm. In the distance are round barns built in the early 1900s, designed to withstand Midwestern windstorms. The sky is a formless white. It’s the day after a storm system hundreds of miles wide rolled through, churning out 80-mile-per-hour gusts and prompting dozens of tornado watches and sirens reminiscent of a Cold War bomb drill.

On about 23 million acres, or roughly two-thirds of the state, farmers grow corn and soybeans, with a smattering of wheat. They generally spray virtually every acre with herbicides, says Hager, who was raised on a farm in Illinois. But these chemicals, which allow one plant species to live unbothered across inconceivably vast spaces, are no longer stopping all the weeds from growing.

Since the 1980s, more and more plants have evolved to become immune to the biochemical mechanisms that herbicides leverage to kill them. This herbicidal resistance threatens to decrease yields—out-of-control weeds can reduce them by 50% or more, and extreme cases can wipe out whole fields. 

At worst, it can even drive farmers out of business. It’s the agricultural equivalent of antibiotic resistance, and it keeps getting worse.

As we drive east from the campus in Champaign-Urbana, the twin cities where I grew up, we spot a soybean field overgrown with dark-green, spiky plants that rise to chest height. 

“So here’s the problem,” Hager says. “That’s all water hemp right there. My guess is it’s been sprayed at least once, if not more than once.”

“With these herbicide-resistant weeds, it’s only going to get worse. It’s going to blow up.”

Water hemp (Amaranthus tuberculatus), which can infest just about any kind of crop field, grows an inch or more a day, and females of the species can easily produce hundreds of thousands of seeds. Native to the Midwest, it has burst forth in much greater abundance over the last few years, because it has become resistant to seven different classes of herbicides. Season-long competition from water hemp can reduce soybean yields by 44% and corn yields by 15%, according to Purdue University Extension.

“We really need a fundamental change in weed control, and we need it quick, ’cause the weeds have caught up to us,” says Larry Steckel, a professor of plant sciences at the University of Tennessee. “It’s come to a pretty critical point.” 

On the rise

According to Ian Heap, a weed scientist who runs the International Herbicide-Resistant Weed Database, there have been well over 500 unique cases of the phenomenon in 273 weed species and counting. Weeds have evolved resistance to 168 different herbicides and 21 of the 31 known “modes of action,” which means the specific biochemical target or pathway a chemical is designed to disrupt. Some modes of action are shared by many herbicides.

One of the most wicked weeds in the South, one that plagues Steckel and his colleagues, is a rhubarb-red-stemmed cousin to water hemp known as Palmer amaranth (Amaranthus palmeri). Populations of the weeds have been found that are impervious to nine different classes of herbicides. The plant can grow more than two inches a day to reach eight feet in height and dominate entire fields. Originally from the desert Southwest, it boasts a sturdy root system and can withstand droughts. If rainy weather or your daughter’s wedding prevents you from spraying it for a couple of days, you’ve probably missed your chance to control it chemically.  

Chemical birth 

Before World War II, farmers generally used cultivators such as plows and harrows to remove weeds and break up the ground. Or they did it by hand—like my mother, who remembers hoeing weeds in cornfields as a kid growing up on an Indiana farm.

That changed with the advent of synthetic pesticides and herbicides, which farmers started using in the 1950s. By the 1970s, some of the first examples of resistance appeared. By the early 1980s, Heap and his colleague Stephen Powles had discovered populations of ryegrass (Lolium rigidum) that were resistant to the most commonly used herbicides, known as ACCase inhibitors, spreading throughout southern Australia. Within a few years, this species had become resistant to yet another class, called ALS-inhibiting herbicides.  

Glyphosate quickly became one of the most widely used agricultural chemicals, and it remains so today. It was so successful, in fact, that research and development on other new herbicides withered: No major commercial herbicide appears likely to hit the market anytime soon that could help address herbicide resistance on a grand scale. 

Monsanto claimed it was “highly unlikely” that glyphosate-resistant weeds would become a problem. There were, of course, those who correctly predicted that such a thing was inevitable—among them Jonathan Gressel, a professor emeritus at the Weizmann Institute of Science in Rehovot, Israel, who has been studying herbicides since the 1960s.

Staying alive

Herbicide resistance is a predictable ­outcome of evolution, explains Patrick Tranel, a leader in the field of molecular weed science at the University of Illinois, whose lab is a few miles from the South Farm. 

“When you try to kill something, what does it do? It tries to not be killed,” Tranel says. 

Weeds have developed surprising ways to get around chemical control. One 2009 study published in the Proceedings of the National Academy of Sciences showed that a mutation in the Palmer amaranth genome allowed the plant to make more than 150 copies of the gene that glyphosate targets. That kind of gene amplification had never been reported in plants before, says Franck Dayan, a weed scientist at Colorado State University.

Another bizarre way resistance can arise in that species is via structures called extrachromosomal circular DNA, strands of genetic material including the gene target for glyphosate that exist outside of nuclear chromosomes. This gene can be transferred via wind-blown pollen from plants with this adaptation. 

“When you try to kill something, what does it do? It tries to not be killed.”

Patrick Tranel, University of Illinois

There’s evidence of resistance developing to both of the chemical groups that have replaced or been mixed with Roundup to kill this weed: an herbicide called glufosinate and a pair of substances known as 2,4-D and dicamba. These two would normally kill many crops, too, but there are now millions of acres of corn and soy genetically modified to be impervious. So essentially the response has been to throw more chemicals at the problem.

Looking for solutions

It’s not just chemicals. Weeds can become resistant to any type of control method. In a classic example from China, a weed called barnyard grass evolved over centuries to resemble rice and thus evade hand weeding.

BELL HUTLEY

Farms have ballooned in size over the last couple of decades, as a result of rural flight, labor costs, and the advent of chemicals and genetically modified crops that allowed farmers to quickly apply herbicides over massive areas to control weeds. This has led to a kind of sinister simplification in terms of crop diversity, weed control practices, and the like. And the weeds have adjusted. 

On the one hand, it’s understandable that farmers often do the cheapest thing they can to control weeds, to get them through the year. But resistance is a medium- to long-term problem running up against a system of short-term thinking and incentives, says Katie Dentzman, a rural sociologist also at Iowa State University.

Her studies have shown that farmers are generally informed and worried about herbicide resistance but are constrained by a variety of factors that prevent them from really heading it off. The farm is too big to economically control weeds without spraying in a single shot, some farmers say, while others lack the labor, financing, or time. 

Agriculture needs to embrace a diversity of weed control practices, Owen says. But that’s much easier said than done. 

“We’re too narrow-visioned, focusing on herbicides as the solution,” says Steven Fennimore, a weed scientist with the University of California, Davis, based in Salinas, California.

Fennimore specializes in vegetables, for which there are few herbicide options, and there are fewer still for organic growers. So innovation is necessary. He developed a prototype that injects steam into the ground, killing weeds within several inches of the entry point. This has proved around 90% effective, and he’s used it in fields growing lettuce, carrots, and onions. But it is not exactly quick: It takes two or three days to treat a 10-acre block.

Many other nonchemical means of control are gaining traction in vegetables and other high-value crops. Eventually, if the economics and logistics work out, these could catch on in row crops, those planted in rows that can be tilled by machinery. 

A company called Carbon Robotics, for example, produces an AI-driven system called the LaserWeeder that, as the name implies, uses lasers to kill weeds. It is designed to pilot itself up and down crop rows, recognizing unwanted plants and vaporizing them with one of its 30 lasers. LaserWeeders are now active in at least 17 states, according to the company.  

You can also shock weeds by using electricity, and several apparatuses designed to do so are commercially available in the United States and Europe. A typical design involves the use of a height-adjustable copper boom that zaps weeds it touches. The most obvious downside with this method is that the weeds usually have to be taller than the crop. By the time the weeds have grown that high, they’ve probably already caused a decline in yield. 

Weed seed destructors are another promising option. These devices, commonly used in Australia and catching on a bit in places like the Pacific Northwest, grind up and kill the seeds of weeds as wheat is harvested.

In general, AI-driven rigs and precision spraying are very likely to eventually reduce herbicide use, says Stephen Duke, who studies herbicides at the University of Mississippi: “Eventually I expect we’ll see robotic weeding and AI-driven spray rigs taking over.” But he expects that to take a while on crops like soybeans and corn, since it is economically difficult to invest a lot of money in tending such “low-value” agronomic crops planted across such vast areas.

A handful of startups are pursuing new types of herbicides, based on natural products found in fungi or used by plants to compete with one another. But none of these promise to be ready for market anytime soon.

Field day 

Some of the most successful tools for preventing resistance are not exactly high-tech. That much is clear from the presentations at the Aurora Farm Field Day, organized by Cornell University just north of its campus in Ithaca, New York. 

For example, one of the most important things farmers can do to prevent the spread of weed seeds is to clean out their combines after harvest, especially if they’re buying or using equipment from another state, says Lynn Sosnoskie, an assistant professor and weed scientist at Cornell. 

Combines are believed to have already introduced Palmer amaranth into the state, she says—there are now at least five populations in New York. 

Another classic approach is crop rotation—switching between crops with different life cycles, management practices, and growth patterns is a mainstay of agriculture, and it helps prevent weeds from becoming accustomed to one cropping system. Yet another option is to put in a winter cover crop that helps prevent weeds from getting established. 

“We’re not going to solve weed problems with chemicals alone,” Sosnoskie says. That means we have to start pursuing these kinds of straightforward practices.

It’s an especially important point to hammer home in places like New York state, where the problem isn’t yet top of mind. That’s in part because the state isn’t dominated by monocultures the way the Midwest is, and it has a more diverse patchwork of land use. 

But it’s not immune to the issue. Resistance has arrived and threatens to “blow up,” says Vipan Kumar, also a weed expert at Cornell.

“We have to do everything we can to prevent this,” Kumar says. “My role is to educate people that this is coming, and we have to be ready.”

Douglas Main is a journalist and former senior editor and writer at National Geographic.

Sales of new electric vehicles in Germany have plummeted, dropping nearly 37% in July 2024 from the same month one year ago.

One of the main reasons traces back to mid-December 2023, when the German government gave less than one week’s notice before ending its subsidy program for electric vehicles. The program had given drivers small grants (up to around €6,000) toward the purchase of new battery-electric and plug-in hybrid cars.

The end of the subsidy program isn’t the only factor contributing to Germany’s EV slowdown, but the abrupt axing certainly had an effect: While many countries across Europe saw steady or growing sales of new EVs in the past year, Germany’s sales fell. It’s not just Germany ending these subsidy programs, either. Sweden and New Zealand have also scrapped their schemes and seen a resulting slowdown or drop in sales. This all comes at a time when the world needs to dramatically ramp up efforts to move to zero-emissions vehicles and pull fossil-fuel-powered ones off the roads to address climate change.

Experts are now cautioning that ending these support systems too soon could jeopardize progress on climate change. As EVs continue to enter the mainstream, the question facing policymakers is how to decide when the technology is ready to stand on its own—something that will likely vary in each market.

Money can be a powerful tool to persuade people to adopt a new technology. “Cost is the main driver,” says Robbie Orvis, senior director for modeling and analysis at Energy Innovation, a policy research firm specializing in energy and climate.

A government’s toolbox to support new tech includes economic incentives, standards and rules, and research and development support. Generally, a mix of those things will be most effective at boosting new technologies, Orvis says.

Economic incentives can either make a new technology cheaper or make the incumbent one more expensive. Either way, they help level the playing field early on in a technology’s development, Orvis says. This pattern played out with solar power—the cost of solar panels is 90% lower than it was just a decade ago, in part because of government programs that subsidized their production. 

Eventually, as the new technology scales, costs should drop until the point when you don’t need incentives anymore and can instead turn to other tools like mandates, he says.

Electric vehicles are being produced in much greater numbers and are much closer in cost to gas-powered ones than they were just a few years ago, but there’s still a difference in the sticker price.

Today, the cost of owning an EV over its entire lifetime rivals the lifetime cost of a gas-powered car. However, electric vehicles often have a higher up-front price and deliver savings over time in the form of cheaper maintenance and operating costs. Gas-powered cars can be cheaper initially but bring higher maintenance and fueling costs over time. 

To bridge this gap, governments around the world have encouraged buyers to purchase EVs by offering subsidies that would make the initial price difference negligible.

Many EV markets in the West have plans for mandates in the future, with some kicking in roughly a decade from now. The European Union, along with some US states, will mandate that all new vehicles sold be zero-emissions by 2035. The question is when governments can safely sunset subsidy programs.

The German government announced in December 2023 that it would be halting EV subsidies, with virtually immediate effect. The move came after the country faced a budget crisis. Germany had paid out €10 billion for 2.1 million electric vehicles since 2016, and the announcement called the program a success. 

This abrupt change contributed to a drop in EV sales in the country in the first half of 2024, according to analysis by the European Federation for Transport and Environment.

The end of German EV subsidies came too early, says Peter Mock, regional lead for Europe at the International Council on Clean Transportation. Most manufacturers are still far from the emissions targets they’re expected to hit by 2025. The sales slump for EVs raises questions about whether manufacturers will be able to hit those targets on time, and some in the auto industry are loudly raising doubts over whether the targets are feasible at all.

Electric vehicles have become much more common on roads around the world, but they’re still a minority option in most markets, reaching 18% of new-vehicle sales globally in 2023.  

Germany’s EV market is in an early, somewhat delicate place. Battery-electric vehicles made up just over 20% of new-vehicle sales in Germany before incentives ended in 2023. This point, Mock explains, falls at what many economists call the chasm separating early adopters (who are often willing to spend more) from majority customers.

Ending a subsidy program will basically always have an effect on sales, though. Even if EVs were significantly cheaper than gas-powered cars, if you took away a big incentive you’d likely see a sales slump, Energy Innovation’s Orvis says. “People still care about the cost,” he adds.

Take Sweden, which ended EV incentives at the end of 2022. The country saw an immediate slump in its sales from December 2022 to January 2023, but the market has roughly leveled out. One reason: The transition there was significantly farther along, with roughly 35% of new vehicles sold being battery-electric in August 2024. If you lump in plug-in hybrids, the share of plug-in vehicles is nearly 50%. Because the market was farther along, there’s not as much concern that the country will see a major stall in moving toward zero-emissions vehicles from fossil-fuel ones, Mock says.

One potential way to address concerns about subsidy cost is to pair them with fees on the incumbent technology. These are sometimes called feebate programs, and they work by adding a fee to a high-emissions vehicle while providing a subsidy for a low-emissions one, Mock says. 

Each country, and even each region within the same country, will have its own unique transition to a new mode of driving. “Each market has to be convinced,” says Robbie Andrew, a senior researcher at the Center for International Climate Research in Norway, who compiles EV sales data.

One key consideration for policymakers in each area should be the speed with which subsidies are sunsetted, Mock says. Giving automakers and consumers a firm schedule in advance can ensure that there’s less of a dramatic shock to the market. Ramping down support slowly over time can also be better than cutting a subsidy to zero in one swoop. 

The German government is already taking steps to improve its falling EV sales. In early September, the government agreed on measures that would allow companies to deduct part of the value of electric vehicles from tax consideration. 

Taking our collective foot off the pedal now when it comes to EV adoption likely won’t doom the technology, but it could be a major setback. And ultimately, what matters is not only that the world adopts technologies to cut emissions in the transportation sector—the speed at which we do so will have massive implications for climate change as well. The longer we drive polluting vehicles, the more emissions will wind up in the atmosphere. And the higher those pollution levels, the more we’ll feel the effects of a warming world. 

In the 1800s, aluminum was considered more valuable than gold or silver because it was so expensive to produce the metal in any quantity. Thanks to the Hall-Héroult smelting process, which pioneered the electrochemical reduction of aluminum oxide in 1886, electrochemistry advancements made aluminum more available and affordable, rapidly transforming it into a core material used in the manufacturing of aircraft, power lines, food-storage containers and more.

As society mobilizes against the pressing climate crisis we face today, we find ourselves seeking transformative solutions to tackle environmental challenges. Much as electrochemistry modernized aluminum production, science holds the key to revolutionizing steel and iron manufacturing.

Electrochemistry can help save the planet

As the world embraces clean energy solutions such as wind turbines, electric vehicles, and solar panels to address the climate crisis, changing how we approach manufacturing becomes critical. Traditional steel production—which requires a significant amount of energy to burn fossil fuels at temperatures exceeding 1,600 °C to convert ore into iron—currently accounts for about 10 percent of the planet’s annual CO₂ emissions. Continuing with conventional methods risks undermining progress toward environmental goals.

Scientists already are applying electrochemistry—which provides direct electrical control of oxidation-reduction reactions—to convert ore into iron. The conversion is an essential step in steel production and the most emissions-spewing part. Electrochemical engineers can drive the shift toward a cleaner steel and iron industry by rethinking and reprioritizing optimizations.

When I first studied engineering thermodynamics in 1998, electricity—which was five times the price per joule of heat—was considered a premium form of energy to be used only when absolutely required.

Since then the price of electricity has steadily decreased. But emissions are now known to be much more harmful and costly.

Engineers today need to adjust currently accepted practices to develop new solutions that prioritize mass efficiency over energy efficiency.

In addition to electrochemical engineers working toward a cleaner steel and iron industry, advancements in technology and cheaper renewables have put us in an “electrochemical moment” that promises change across multiple sectors.

The plummeting cost of photovoltaic panels and wind turbines, for example, has led to more affordable renewable electricity. Advances in electrical distribution systems that were designed for electric vehicles can be repurposed for modular electrochemical reactors.

Electrochemistry holds the potential to support the development of clean, green infrastructure beyond batteries, electrolyzers, and fuel cells. Electrochemical processes and methods can be scaled to produce metals, ceramics, composites, and even polymers at scales previously reserved for thermochemical processes. With enough effort and thought, electrochemical production can lead to billions of tons of metal, concrete, and plastic. And because electrochemistry directly accesses the electron transfer fundamental to chemistry, the same materials can be recycled using renewable energy.

As renewables are expected to account for more than 90 percent of global electricity expansion during the next five years, scientists and engineers focused on electrochemistry must figure out how best to utilize low-cost wind and solar energy.

The core components of electrochemical systems, including complex oxides, corrosion-resistant metals, and high-power precision power converters, are now an exciting set of tools for the next evolution of electrochemical engineering.

The scientists who came before have created a stable set of building blocks; the next generation of electrochemical engineers needs to use them to create elegant, reliable reactors and other systems to produce the processes of the future.

Three decades ago, electrochemical engineering courses were, for the most part, electives and graduate-level. Now almost every institutional top-ranked R&D center has full tracks of electrochemical engineering. Students interested in the field should take both electroanalytical chemistry and electrochemical methods classes and electrochemical energy storage and materials processing coursework.

Although scaled electrochemical production is possible, it is not inevitable. It will require the combined efforts of the next generation of engineers to reach its potential scale.

Just as scientists found a way to unlock the potential of the abundant, once-unattainable aluminum, engineers now have the opportunity to shape a cleaner, more sustainable future. Electrochemistry has the power to flip the switch to clean energy, paving the way for a world in which environmental harmony and industrial progress go hand in hand.

According to the International Maritime Organization, shipping was responsible for over 1 billion tonnes of carbon dioxide emissions in 2018. A significant share of those emissions came from seaport activities, including ship berthing, cargo handling, and transportation within port areas. In response, governments, NGOs, and environmental watchdog groups are sounding alarms and advocating for urgent measures to mitigate pollution at the world’s ports.

One of the most promising solutions for the decarbonization of port operations involves electrifying these facilities. This plan envisions ships plugging into dockside electric power rather than running their diesel-powered auxiliary generators for lighting, cargo handling, heating and cooling, accommodation, and onboard electronics. It would also call for replacing diesel-powered cranes, forklifts, and trucks that move massive shipping containers from ship to shore with battery-powered alternatives.

To delve deeper into this transformative approach, IEEE Spectrum recently spoke with John Prousalidis, a leading advocate for seaport electrification. Prousalidis, a professor of marine electrical engineering at the National Technical University of Athens, has played a pivotal role in developing standards for seaport electrification through his involvement with the IEEE, the International Electrical Commission (IEC), and the International Organization for Standardization (ISO). As vice-chair of the IEEE Marine Power Systems Coordinating Committee, he has been instrumental in advancing these ideas. Last year, Prousalidis co-authored a key paper titled “Holistic Energy Transformation of Ports: The Proteus Plan” in IEEE Electrification Magazine. In the paper, Prousalidis and his co-authors outlined their comprehensive vision for the future of port operations. The main points of the Proteus plan have been integrated in the policy document on Smart and Sustainable Ports coordinated by Prousalidis within the European Public Policy Committee Working Group on Energy; the policy document was approved in July 2024 by the IEEE Global Policy Committee.

Professor John ProusalidisJohn Prousalidis

What exactly is “cold ironing?”

John Prousalidis: Cold ironing involves shutting down a ship’s propulsion and auxiliary engines while at port, and instead, using electricity from shore to power onboard systems like air conditioning, cargo handling equipment, kitchens, and lighting. This reduces emissions because electricity from the grid, especially from renewable sources, is more environmentally friendly than burning diesel fuel on site. The technical challenges include matching the ship’s voltage and frequency with that of the local grid, which, in general, varies globally, while tackling grounding issues to protect against short circuits.

IEEE, along with IEC and ISO, have developed a joint standard, 80005, which is a series of three different standards for high-voltage and low-voltage connection. It is perhaps (along with Wi-Fi, the standard for wireless communication) the “hottest” standard because all governmental bodies tend to make laws stipulating that this is the standard that all ports need to follow to supply power to ships.

How broad has adoption of this standard been?

Prousalidis: The European Union has mandated full compliance by January 1, 2030. In the United States, California led the way with similar measures in 2010. This aggressive remediation via electrification is now being adopted globally, with support from the International Maritime Organization.

Let’s talk about another interesting idea that’s part of the plan: regenerative braking on cranes. How does that work?

Prousalidis: When lowering shipping containers, cranes in regenerative braking mode convert the kinetic energy into electric charge instead of wasting it as heat. Just like when an electric vehicle is coming to a stop, the energy can be fed back into the crane’s battery, potentially saving up to 50 percent in energy costs—though a conservative estimate would be around 20 percent.

What are the estimated upfront costs for implementing cold ironing at, say, the Port of Los Angeles, which is the largest port in the United States?

Prousalidis: The cost for a turnkey solution is approximately US $1.7 million per megawatt, covering grid upgrades, infrastructure, and equipment. A rough estimate using some established rules of thumb would be about $300 million. The electrification process at that port has already begun. There are, as far as I know, about 60 or more electrical connection points for ships at berths there.

How significant would the carbon reduction from present levels be if there were complete electrification with renewable energy at the world’s 10 biggest and busiest ports?

Prousalidis: If ports fully electrify using renewable energy, the European Union’s policy could achieve a 100-percent reduction in ship emissions in the port areas. According to the IMO’s approach, which considers the energy mix of each country, it could lead to a 60-percent reduction. This significant emission reduction means lower emissions of CO₂, nitrogen oxides, sulfur oxides, and particulate matter, thus reducing shipping’s contribution to global warming and lowering health risks in nearby population centers.

If all goes according to plan, and every country with port operations goes full bore toward electrification, how long do you think it will realistically take to completely decarbonize that aspect of shipping?

Prousalidis: As I said, the European Union is targeting full port electrification by 1 January 2030. However, with around 600 to 700 ports in Europe alone, and the need for grid upgrades, delays are possible. Despite this, we should focus on meeting the 2030 deadline rather than anticipating extensions. This recalls the words of Gemini and Apollo pioneer astronaut, Alan Shepard, when he explained the difference between a test pilot and a normal professional pilot: “Suppose each of them had 10 seconds before crashing. The conventional pilot would think, In 10 seconds I’m going to die. The test pilot would say to himself, I’ve got 10 seconds to save myself and save the craft.” The point is that, in a critical situation like the fight against global warming, we should focus on the time we have to solve the problem, not on what happens after time runs out. But humanity doesn’t have an eject button to press if we don’t make every effort to avoid the detrimental consequences that will come with failure of the “save the planet” projects.

A maze of brackish and freshwater ponds covers Taiwan’s coastal plain, supporting aquaculture operations that produce roughly NT $30 billion (US $920 million) worth of seafood every year. Taiwan’s government is hoping that the more than 400 square kilometers of fishponds can simultaneously produce a second harvest: solar power.

What is aquavoltaics?

That’s the impetus behind the new 42.9-megawatt aquavoltaics facility in the southern city of Tainan. To build it, Taipei-based Hongde Renewable Energy bought 57.6 hectares of abandoned land in Tainan’s fishpond-rich Qigu district, created earthen berms to delineate the two dozen ponds, and installed solar panels along the berms and over six reservoir ponds.

Tony Chang, general manager of the Hongde subsidiary Star Aquaculture, says 18 of the ponds are stocked with mullet (prized for their roe) and shrimp, while milkfish help clean the water in the reservoir ponds. In 2023, the first full year of operation, Chang says his team harvested over 100,000 kilograms of seafood. This August, they began stocking a cavernous indoor facility, also festooned with photovoltaics, to cultivate white-legged shrimp.

A number of other countries have been experimenting with aquavoltaics, including China, Chile, Bangladesh, and Norway, extending the concept to large solar arrays floating on rivers and bays. But nowhere else is the pairing of aquaculture and solar power seen as so crucial to the economy. Taiwan is striving to massively expand renewable generation to sustain its semiconductor fabs, and solar is expected to play a large role. But on this densely populated island—slightly larger than Maryland, smaller than the Netherlands—there’s not a lot of open space to install solar panels. The fishponds are hard to ignore. By the end of 2025, the government is looking to install 4.4 gigawatts of aquavoltaics to help meet its goal of 20 GW of solar generation.

Is Taiwan’s aquavoltaics plan unrealistic?

Meanwhile, though, solar developers are struggling to deliver on Taiwan’s ambitious goals, even as some projections suggest Taiwan will need over eight times more solar by 2050. And aquavoltaics in particular have come under scrutiny from environmental groups. In 2020, for example, reporter Cai Jiashan visited 100 solar plants built on agricultural land, including fishponds, and found dozens of cases where solar developers built more solar capacity than the law intended, or secured permits based on promises of continued farming that weren’t kept.

Star Aquaculture grows milkfish to help clean water for its breeding ponds.HDRenewables

On 7 July 2020, Taiwan’s Ministry of Agriculture responded by restricting solar development on farmland, in what the solar industry called the “Double-Seven Incident.” Many aquavoltaic projects were canceled while others were delayed. The latter included a 10-MW facility in Tainan that Google had announced to great fanfare in 2019 as its first renewable-energy investment in Asia, to supply power for the company’s Taiwan data centers. The array finally started up in 2023, three years behind schedule.

Critics of Taiwan’s renewed aquavoltaic plans thus see the government’s goal as unrealistic. Yuping Chen, executive director of the Taiwan Environment and Planning Association, a Taipei-based nonprofit dedicated to resolving conflicts between solar energy and agriculture, says of aquavoltaics, “It is claimed to be crucial by the government, but it’s impossible to realize.”

How aquavoltaics could revive fishing, boost revenue

Solar developers and government officials who endorse aquavoltaics argue that such projects could revive the island’s traditional fishing community. Taiwan’s fishing villages are aging and shrinking as younger people take city jobs. Climate change has also taken a toll. Severe storms damage fishpond embankments, while extreme heat and rainfall stress the fish.

4.4

Gigawatts of aquavoltaics that Taiwan wants to install by the end of 2025

Solar development could help reverse these trends. Several recent studies examining fishponds in Taiwan found that adding solar improves profitability, providing an opportunity to reinvigorate communities if agrivoltaic investors share their returns. Alan Wu, deputy director of the Green Energy Initiative at Taiwan’s Industrial Technology Research Institute, says the Hsinchu-based lab has opened a research station in Tainan to connect solar and aquaculture firms. ITRI is helping aquavoltaics facilities boost their revenues by figuring out how they can raise “species of high economic value that are normally more difficult to raise,” Wu says.

Such high-value products include the 27,000 pieces of sun-dried mullet roe that Hongde Renewable Energy’s Tainan site produced last year. The new indoor facility, meanwhile, should boost yields of the relatively pricey whiteleg shrimp. Chang expects the indoor harvests to fetch $500,000 to $600,000 annually, compared to $800,000 to $900,000 from the larger outdoor ponds.

The solar roof over the 100,000-liter indoor growth tanks protects the 2.7 million shrimp against weather and bird droppings. Chang says a patent-pending drain mechanically removes waste from each tank, and also sucks out the shrimp when they’re ready for harvest.

Land that Star Aquaculture set aside for wildlife now attracts endangered birds like the black-faced spoonbill [left] and the oriental stork [right].iStock (2)

The company has also set aside 9 percent of the site for wildlife, in response to concerns from conservationists. “Egrets, endangered oriental storks, and black-faced spoonbills continue to use the site,” Chang says. “If it was all covered with PV, it could impact their habitat.”

Such measures may not satisfy environmentalists, though. In a review published last month, researchers at Fudan University in Shanghai and two Chinese power firms concluded that China’s floating aquavoltaic installations—some of which already span 5 square kilometers—will “inevitably” alter the marine environment.

Aquavoltaic facilities that are entirely indoors may be an even harder sell as they scale up. Toshiba is backing such a plant in Tainan, to generate 120 MW for an unspecified “semiconductor manufacturer,” with plans for a 360-MW expansion. The resulting buildings could exclude wildlife from 5 square kilometers of habitat. Indoor projects could compensate by protecting land elsewhere. But, as Chen of the Taiwan Environment and Planning Association notes, developers of such sites may not take such measures unless they’re required by law to do so.