When Rattan Lal was awarded the Japan Prize for Biological Production, Ecology in April—the Asian equivalent of a Nobel—the audience at Tokyo's National Theatre included the emperor and empress. Lal's acceptance speech, however, was down-to-earth in the most literal sense.
Carbon, in its proper place, holds landscapes and ecosystems together.
"I'd like to begin, rather unconventionally, with the conclusion of my presentation," he told the assembled dignitaries. "And the conclusion is four words: In soil we trust."
That statement could serve as the motto for a climate crisis-fighting strategy that has gained remarkable momentum over the past five years or so—and whose rise to international prominence was reflected in that glittering award ceremony. Lal, a septuagenarian professor of soil science at Ohio State University, is one of the foremost exponents of carbon farming, an approach that centers on correcting a man-made, planetary chemical imbalance.
A Solution to Several Problems at Once?
The chemical in question is carbon. Too much of it in the atmosphere (in the form of carbon dioxide, a potent greenhouse gas) is the main driver of global heating. Too little of it in the soil is the bane of farmers in many parts of the world, and a threat to our ability to feed a ballooning global population. Advocates say agriculture can mitigate both problems—by adopting techniques that keep more soil carbon from escaping skyward, and draw more atmospheric carbon down into fields and pastures.
The potential impacts go beyond slowing climate change and boosting food production. "There are so many benefits," says Lal. "Water quality, drought, flooding, biodiversity—this is a natural solution for all these problems." That's because carbon, in its proper place, holds landscapes and ecosystems together. Plants extract it from the air and convert it into sugars for energy; they also transfer it to the soil through their roots and in the process of decomposition. In the ground, carbon feeds microbes and fungi that form the basis of complex food webs. It helps soil absorb and retain water, resist erosion, and hold onto nitrogen and phosphorous—keeping those nutrients from running off into waterways and creating toxic algal blooms.
Government and private support for research into carbon-conscious agriculture is on the rise, and growing numbers of farmers are exploring such methods. How much difference these methods can make, however, remains a matter of debate. Lal sees carbon farming as a way to buy time until CO2 emissions can be brought under control. Skeptics insist that such projections are overly optimistic. Some allies, meanwhile, think Lal's vision is too timid. "Farming can actually fix the climate," says Tim LaSalle, co-founder of the Center for Regenerative Agriculture at California State University, Chico. "That should be our only focus."
Yet Can soil solve the climate crisis? may be not be the key question in assessing the promise of carbon farming, since it implies that action is worthwhile only if a solution is ensured. A more urgent line of inquiry might be: Can the climate crisis be solved without addressing soil?
A Chance Meeting Leads to the Mission of a Lifetime
Lal was among the earliest scientists to grapple with that question. Born in Pakistan, he grew up on a tiny subsistence farm in India, where his family had fled as refugees. The only one of his siblings who learned to read and write, he attended a local agricultural university, then headed to Ohio State on scholarship for his PhD. In 1982, he was working at the International Institute of Tropical Agriculture in Nigeria, trying to develop sustainable alternatives to Africa's traditional slash-and-burn farming, when a distinguished visitor dropped by: oceanographer Roger Revelle, who 25 years earlier had published the first paper warning that fossil fuel combustion could throw the climate dangerously off-kilter.
Rattan Lal, Distinguished University Professor of Soil Science at Ohio State, received the Japan Prize at a ceremony in April.
(Photo: Ken Chamberlain. CFAES.)
Lal showed Revelle the soil in his test plots—hard and reddish, like much of Africa's agricultural land. Then (as described in Kristin Ohlson's book The Soil Will Save Us), he led the visitor to the nearby forest, where the soil was dark, soft, and wriggling with earthworms. In the forest, the soil's carbon content was 2 to 3 percent; in Lal's plots, it had dwindled to 0.5 percent. When Revelle asked him where all that carbon had gone, Lal confessed he didn't know. Revelle suggested that much of it might have floated into the atmosphere, adding to the burden of greenhouse gases. "Since then," Lal told me, "I've been looking for ways to put it back."
Back at Ohio State, Lal found that the United States Department of Agriculture (USDA) and Environmental Protection Agency (EPA) were also interested in the connection between soil carbon and climate change. With a small group of other scientists, he began investigating the dimensions of the problem, and how it might be solved.
Comparing carbon in forested and cultivated soils around the globe, the researchers calculated that about 100 billion tons had vanished into the air since the dawn of agriculture 10,000 years ago. The culprits were common practices—including plowing, overgrazing, and keeping fallow fields bare—that exposed soil carbon to oxygen, transforming it into carbon dioxide. Yet the process could also be reversed, Lal and his colleagues argued. Although there was a limit to the amount of carbon that soil could hold, they theorized that it would be possible to sequester several billion tons of global CO2 emissions each year for decades before reaching maximum capacity.
Lal set up projects on five continents to explore practices that could help accomplish that goal, such as minimizing tillage, planting cover crops, and leaving residue on fields after harvest. He organized conferences, pumped out papers and books. As other researchers launched similar efforts, policymakers worldwide took notice.
But before long, recalls Colorado State University soil scientist Keith Paustian (a fellow carbon-farming pioneer, who served with Lal on the UN's International Panel on Climate Change), official attention "kind of faded away. The bigger imperative was to cut emissions." And because agriculture accounted for only about 13 percent of greenhouse gas pollution, Paustian says, the sectors that emitted the most—energy and transportation—got the bulk of funding.
A Movement on the Rise
In recent years, however, carbon farming has begun to look like an idea whose time has come. One factor is that efforts to reduce emissions haven't worked; in 2018 alone, global CO2 output rose by an estimated 2.7 percent, according to the Global Carbon Project. Last month, researchers from the Scripps Institute of Oceanography reported that atmospheric CO2—under 350 ppm when Lal began his quest—had reached 415 ppm, the highest in 3 million years. And with the world's population expected to approach 10 billion by 2050, the need for sustainable technologies to augment food production has grown increasingly pressing.
Today, carbon-conscious methods are central to the burgeoning movement known as "regenerative agriculture," which also embraces other practices aimed at improving soil health and farming in an ecologically sound (though not always strictly organic) manner. In the United States, the latest Farm Bill includes $25 million to incentivize soil-based carbon sequestration. State and local governments across the country are supporting such efforts, as are at least a dozen nonprofits. The Department of Energy's Advanced Projects Research Agency (ARPA-e) is working to develop crops and technologies aimed at increasing soil carbon accumulation by 50 percent. General Mills recently announced plans to advance regenerative farming on 1 million acres by 2030, and many smaller companies have made their own commitments.
The toughest challenge, Lal suggests, may be persuading farmers to change their ways.
Internationally, the biggest initiative is the French-led "4 per 1,000" initiative, which aims to increase the amount of carbon in the soil of farms and rangelands worldwide by 0.4 percent per year—a rate that the project's website contends would "halt the increase of CO2 (carbon dioxide) concentration in the atmosphere related to human activities."
Given the current pace of research, Lal believes that goal—which equates to sequestering 3.6 billion tons of CO2 annually, or 10 percent of global emissions—is doable. The toughest challenge, he suggests, may be persuading farmers to change their ways. Although carbon farming can reduce costs for chemical inputs such as herbicides and fertilizers, while building rich topsoil, agriculturalists tend to be a conservative lot.
And getting low-income farmers to leave crop residue on fields, instead of using it for fuel or animal feed, will require more than speeches about melting glaciers. Lal proposes a $16 per acre subsidy, totaling $64 billion for the world's 4 billion acres of cropland. "That's not a very large amount," he says, "if you're investing in the health of the planet."
Experimental Methods Attract Supporters and Skeptics
Some experts question whether enough CO2 can be stashed in the soil to prevent the rise in average global temperature from surpassing the 2º C mark—set by the 2016 Paris Agreement as the limit beyond which climate change would become catastrophic. But others insist that carbon farming's goal should be to reverse climate change, not just to put it on pause.
"That's the only way out of this predicament," says Tim LaSalle, whose Center for Regenerative Agriculture supports the use of experimental methods ranging from multi-species cover cropping to fungal-dominant compost solutions. Using such techniques, a few researchers and farmers claim to be able to transfer carbon to the soil at rates many times higher than with established practices. Although several of these methods have yet to be documented in peer-reviewed studies, LaSalle believes they point the way forward. "We can't fix the climate, or even come close to it, using Rattan's numbers," he says, referring to Lal. "If we can replicate these experiments, we can fix it."
Even scientists sympathetic to regenerative ag warn that relying on unproven techniques is risky. "Some of these claims are beyond anything we've seen in agricultural science," says Andrew McGuire, an agronomist at Washington State University. "They could be right, but extraordinary claims require extraordinary evidence."
Still, the assorted methods currently being tested—which also include amending soil with biochar (made by heating agricultural wastes with minimal oxygen), planting long-rooted perennial crops instead of short-rooted annuals, and deploying grazing animals in ways that enrich soil rather than depleting it—offer a catalogue of hope at a time when environmental despair is all too tempting.
Last October, the National Academy of Sciences, Engineering, and Medicine issued a report acknowledging that it was too late to stave off apocalyptic overheating just by reducing CO2 emissions; removing carbon from the atmosphere would be necessary as well. The document laid out several options for doing so—most of which, it cautioned, had serious limitations.
"Soil is a bridge to the future. We can't do without it."
One possibility was planting more forests. To absorb enough carbon dioxide, however, trees might have to replace areas of farmland, reducing the food supply. Another option was creating biomass plantations to fuel power plants, whose emissions would be stored underground. But land use would be a problem: "You'd need to cover an area the size of India," explains Paustian, who was a co-author of the report. Yet another alternative was direct-air capture, in which chemical processes would be used to extract CO2 from the air. The technology was still in its infancy, though—and the costs and power requirements would likely be astronomical.
The report took up agriculture-based methods on page 95. Those needed further research as well, the authors wrote, to determine which approaches would be most effective. But of all the alternatives, this one seemed the least problematic. "Soil carbon is probably what you can do first, cheapest, and with the most additional co-benefits," says Paustian. "If we can make progress in that area, it's a huge advantage."
In any case, he and other researchers agree, we have little choice but to try. "Soil is a bridge to the future," Lal says. "We can't do without it."
In November 2020, messenger RNA catapulted into the public consciousness when the first COVID-19 vaccines were authorized for emergency use. Around the same time, an equally groundbreaking yet relatively unheralded application of mRNA technology was taking place at a London hospital.
Over the past two decades, there's been increasing interest in harnessing mRNA — molecules present in all of our cells that act like digital tape recorders, copying instructions from DNA in the cell nucleus and carrying them to the protein-making structures — to create a whole new class of therapeutics.
Scientists realized that artificial mRNA, designed in the lab, could be used to instruct our cells to produce certain antibodies, turning our bodies into vaccine-making factories, or to recognize and attack tumors. More recently, researchers recognized that mRNA could also be used to make another groundbreaking technology far more accessible to more patients: gene editing. The gene-editing tool CRISPR has generated plenty of hype for its potential to cure inherited diseases. But delivering CRISPR to the body is complicated and costly.
"Most gene editing involves taking cells out of the patient, treating them and then giving them back, which is an extremely expensive process," explains Drew Weissman, professor of medicine at the University of Pennsylvania, who was involved in developing the mRNA technology behind the COVID-19 vaccines.
But last November, a Massachusetts-based biotech company called Intellia Therapeutics showed it was possible to use mRNA to make the CRISPR system inside the body, eliminating the need to extract cells out of the body and edit them in a lab. Just as mRNA can instruct our cells to produce antibodies against a viral infection, it can also teach them to produce the two molecular components that make up CRISPR — a guide molecule and a cutting protein — to snip out a problem gene.
"The pandemic has really shown that not only are mRNA approaches viable, they could in certain circumstances be vastly superior to more traditional technologies."
In Intellia's London-based clinical trial, the company applied this for the first time in a patient with a rare inherited liver disease known as hereditary transthyretin amyloidosis with polyneuropathy. The disease causes a toxic protein to build up in a person's organs and is typically fatal. In a company press release, Intellia's president and CEO John Leonard swiftly declared that its mRNA-based CRISPR therapy could usher in a "new era of potential genome editing cures."
Weissman predicts that turning CRISPR into an affordable therapy will become the next major frontier for mRNA over the coming decade. His lab is currently working on an mRNA-based CRISPR treatment for sickle cell disease. More than 300,000 babies are born with sickle cell every year, mainly in lower income nations.
"There is a FDA-approved cure, but it involves taking the bone marrow out of the person, and then giving it back which is prohibitively expensive," he says. It also requires a patient to have a matched bone marrow done. "We give an intravenous injection of mRNA lipid nanoparticles that target CRISPR to the bone marrow stem cells in the patient, which is easy, and much less expensive."
Meanwhile, the overwhelming success of the COVID-19 vaccines has focused attention on other ways of using mRNA to bolster the immune system against threats ranging from other infectious diseases to cancer.
The practicality of mRNA vaccines – relatively small quantities are required to induce an antibody response – coupled with their adaptable design, mean companies like Moderna are now targeting pathogens like Zika, chikungunya and cytomegalovirus, or CMV, which previously considered commercially unviable for vaccine developers. This is because outbreaks have been relatively sporadic, and these viruses mainly affect people in low-income nations who can't afford to pay premium prices for a vaccine. But mRNA technology means that jabs could be produced on a flexible basis, when required, at relatively low cost.
Other scientists suggest that mRNA could even provide a means of developing a universal influenza vaccine, a goal that's long been the Holy Grail for vaccinologists around the world.
"The mRNA technology allows you to pick out bits of the virus that you want to induce immunity to," says Michael Mulqueen, vice president of business development at eTheRNA, a Belgium-based biotech that's developing mRNA-based vaccines for malaria and HIV, as well as various forms of cancer. "This means you can get the immune system primed to the bits of the virus that don't vary so much between strains. So you could actually have a single vaccine that protects against a whole raft of different variants of the same virus, offering more universal coverage."
Before mRNA became synonymous with vaccines, its biggest potential was for cancer treatments. BioNTech, the German biotech company that collaborated with Pfizer to develop the first authorized COVID-19 vaccine, was initially founded to utilize mRNA for personalized cancer treatments, and the company remains interested in cancers ranging from melanoma to breast cancer.
One of the major hurdles in treating cancer has been the fact that tumors can look very different from one person to the next. It's why conventional approaches, such as chemotherapy or radiation, don't work for every patient. But weaponizing mRNA against cancer primes the immune cells with the tumor's specific genetic sequence, training the patient's body to attack their own unique type of cancer.
"It means you're able to think about personalizing cancer treatments down to specific subgroups of patients," says Mulqueen. "For example, eTheRNA are developing a renal cell carcinoma treatment which will be targeted at around 20% of these patients, who have specific tumor types. We're hoping to take that to human trials next year, but the challenge is trying to identify the right patients for the treatment at an early stage."
Repairing Damaged mRNA
While hopes are high that mRNA could usher in new cancer treatments and make CRISPR more accessible, a growing number of companies are also exploring an alternative to gene editing, known as RNA editing.
In genetic disorders, the mRNA in certain cells is impaired due to a rogue gene defect, and so the body ceases to produce a particular vital protein. Instead of permanently deleting the problem gene with CRISPR, the idea behind RNA editing is to inject small pieces of synthetic mRNA to repair the existing mRNA. Scientists think this approach will allow normal protein production to resume.
Over the past few years, this approach has gathered momentum, as some researchers have recognized that it holds certain key advantages over CRISPR. Companies from Belgium to Japan are now looking at RNA editing to treat all kinds of disorders, from Huntingdon's disease, to amyotrophic lateral sclerosis, or ALS, and certain types of cancer.
"With RNA editing, you don't need to make any changes to the DNA," explains Daniel de Boer, CEO of Dutch biotech ProQR, which is looking to treat rare genetic disorders that cause blindness. "Changes to the DNA are permanent, so if something goes wrong, that may not be desirable. With RNA editing, it's a temporary change, so we dose patients with our drugs once or twice a year."
Last month, ProQR reported a landmark case study, in which a patient with a rare form of blindness called Leber congenital amaurosis, which affects the retina at the back of the eye, recovered vision after three months of treatment.
"We have seen that this RNA therapy restores vision in people that were completely blind for a year or so," says de Boer. "They were able to see again, to read again. We think there are a large number of other genetic diseases we could go after with this technology. There are thousands of different mutations that can lead to blindness, and we think this technology can target approximately 25% of them."
Ultimately, there's likely to be a role for both RNA editing and CRISPR, depending on the disease. "I think CRISPR is ideally suited for illnesses where you would like to permanently correct a genetic defect," says Joshua Rosenthal of the Marine Biology Laboratory in Chicago. "Whereas RNA editing could be used to treat things like pain, where you might want to reset a neural circuit temporarily over a shorter period of time."
Much of this research has been accelerated by the COVID-19 pandemic, which has played a major role in bringing mRNA to the forefront of people's minds as a therapeutic.
"The pandemic has really shown that not only are mRNA approaches viable, they could in certain circumstances be vastly superior to more traditional technologies," says Mulqueen. "In the future, I would not be surprised if many of the top pharma products are mRNA derived."
"Making Sense of Science" is a monthly podcast that features interviews with leading medical and scientific experts about the latest developments and the big ethical and societal questions they raise. This episode is hosted by science and biotech journalist Emily Mullin, summer editor of the award-winning science outlet Leaps.org.