Adapting Plants to Feed the World

Credit: Edwin Remsberg Getty Images

Writing in the Atlantic, Charles Mann raises an important question: Can Planet Earth Feed 10 Billion People? Humanity has 30 years to find out.  Excerpts below with my images and bolds.

Context

In 1970, when I was in high school, about one out of every four people was hungry—“undernourished,” to use the term preferred today by the United Nations. Today the proportion has fallen to roughly one out of 10. In those four-plus decades, the global average life span has, astoundingly, risen by more than 11 years; most of the increase occurred in poor places. Hundreds of millions of people in Asia, Latin America, and Africa have lifted themselves from destitution into something like the middle class. This enrichment has not occurred evenly or equitably: Millions upon millions are not prosperous. Still, nothing like this surge of well-being has ever happened before. No one knows whether the rise can continue, or whether our current affluence can be sustained.

Today the world has about 7.6 billion inhabitants. Most demographers believe that by about 2050, that number will reach 10 billion or a bit less. Around this time, our population will probably begin to level off. As a species, we will be at about “replacement level”: On average, each couple will have just enough children to replace themselves. All the while, economists say, the world’s development should continue, however unevenly. The implication is that when my daughter is my age, a sizable percentage of the world’s 10 billion people will be middle-class.

Like other parents, I want my children to be comfortable in their adult lives. But in the hospital parking lot, this suddenly seemed unlikely. Ten billion mouths, I thought. Three billion more middle-class appetites. How can they possibly be satisfied? But that is only part of the question. The full question is: How can we provide for everyone without making the planet uninhabitable?

Two Schools of Plant Development: Followers of William Vogt and Norman Borlaug

Both men thought of themselves as using new scientific knowledge to face a planetary crisis. But that is where the similarity ends. For Borlaug, human ingenuity was the solution to our problems. One example: By using the advanced methods of the Green Revolution to increase per-acre yields, he argued, farmers would not have to plant as many acres, an idea researchers now call the “Borlaug hypothesis.” Vogt’s views were the opposite: The solution, he said, was to use ecological knowledge to get smaller. Rather than grow more grain to produce more meat, humankind should, as his followers say, “eat lower on the food chain,” to lighten the burden on Earth’s ecosystems. This is where Vogt differed from his predecessor, Robert Malthus, who famously predicted that societies would inevitably run out of food because they would always have too many children. Vogt, shifting the argument, said that we may be able to grow enough food, but at the cost of wrecking the world’s ecosystems.

I think of the adherents of these two perspectives as “Wizards” and “Prophets.” Wizards, following Borlaug’s model, unveil technological fixes; Prophets, looking to Vogt, decry the consequences of our heedlessness.

Even though the global population in 2050 will be just 25 percent higher than it is now, typical projections claim that farmers will have to boost food output by 50 to 100 percent. The main reason is that increased affluence has always multiplied the demand for animal products such as cheese, dairy, fish, and especially meat—and growing feed for animals requires much more land, water, and energy than producing food simply by growing and eating plants. Exactly how much more meat tomorrow’s billions will want to consume is unpredictable, but if they are anywhere near as carnivorous as today’s Westerners, the task will be huge. And, Prophets warn, so will the planetary disasters that will come of trying to satisfy the world’s desire for burgers and bacon: ravaged landscapes, struggles over water, and land grabs that leave millions of farmers in poor countries with no means of survival.

What to do? Some of the strategies that were available during the first Green Revolution aren’t anymore. Farmers can’t plant much more land, because almost every accessible acre of arable soil is already in use. Nor can the use of fertilizer be increased; it is already being overused everywhere except some parts of Africa, and the runoff is polluting rivers, lakes, and oceans. Irrigation, too, cannot be greatly expanded—most land that can be irrigated already is. Wizards think the best course is to use genetic modification to create more-productive crops. Prophets see that as a route to further overwhelming the planet’s carrying capacity. We must go in the opposite direction, they say: use less land, waste less water, stop pouring chemicals into both.

The Rub is Rubisco

All the while that Wizards were championing synthetic fertilizer and Prophets were denouncing it, they were united in ignorance: Nobody knew why plants were so dependent on nitrogen. Only after the Second World War did scientists discover that plants need nitrogen chiefly to make a protein called rubisco, a prima donna in the dance of interactions that is photosynthesis.

In photosynthesis, as children learn in school, plants use energy from the sun to tear apart carbon dioxide and water, blending their constituents into the compounds necessary to make roots, stems, leaves, and seeds. Rubisco is an enzyme that plays a key role in the process. Enzymes are biological catalysts. Like jaywalking pedestrians who cause automobile accidents but escape untouched, enzymes cause biochemical reactions to occur but are unchanged by those reactions. Rubisco takes carbon dioxide from the air, inserts it into the maelstrom of photosynthesis, then goes back for more. Because these movements are central to the process, photosynthesis walks at the speed of rubisco.

Alas, rubisco is, by biological standards, a sluggard, a lazybones, a couch potato. Whereas typical enzyme molecules catalyze thousands of reactions a second, rubisco molecules deign to involve themselves with just two or three a second. Worse, rubisco is inept. As many as two out of every five times, rubisco fumblingly picks up oxygen instead of carbon dioxide, causing the chain of reactions in photosynthesis to break down and have to restart, wasting energy and water. Years ago I talked with biologists about photosynthesis for a magazine article. Not one had a good word to say about rubisco. “Nearly the world’s worst, most incompetent enzyme,” said one researcher. “Not one of evolution’s finest efforts,” said another. To overcome rubisco’s lassitude and maladroitness, plants make a lot of it, requiring a lot of nitrogen to do so. As much as half of the protein in many plant leaves, by weight, is rubisco—it is often said to be the world’s most abundant protein. One estimate is that plants and microorganisms contain more than 11 pounds of rubisco for every person on Earth.

The Promise of C4 Photosynthesis

Evolution, one would think, should have improved rubisco. No such luck. But it did produce a work-around: C4 photosynthesis (C4 refers to a four-carbon molecule involved in the scheme). At once a biochemical kludge and a clever mechanism for turbocharging plant growth, C4 photosynthesis consists of a wholesale reorganization of leaf anatomy.

When carbon dioxide comes into a C4 leaf, it is initially grabbed not by rubisco but by a different enzyme that uses it to form a compound that is then pumped into special, rubisco-filled cells deep in the leaf. These cells have almost no oxygen, so rubisco can’t bumblingly grab the wrong molecule. The end result is exactly the same sugars, starches, and cellulose that ordinary photosynthesis produces, except much faster. C4 plants need less water and fertilizer than ordinary plants, because they don’t waste water on rubisco’s mistakes. In the sort of convergence that makes biologists snap to attention, C4 photosynthesis has arisen independently more than 60 times. Corn, tumbleweed, crabgrass, sugarcane, and Bermuda grass—all of these very different plants evolved C4 photosynthesis.

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Balinese Rice Fields

The Rice Consortium Moonshot

In the botanical equivalent of a moonshot, scientists from around the world are trying to convert rice into a C4 plant—one that would grow faster, require less water and fertilizer, and produce more grain. The scope and audacity of the project are hard to overstate. Rice is the world’s most important foodstuff, the staple crop for more than half the global population, a food so embedded in Asian culture that the words rice and meal are variants of each other in both Chinese and Japanese. Nobody can predict with confidence how much more rice farmers will need to grow by 2050, but estimates range up to a 40 percent rise, driven by both increasing population numbers and increasing affluence, which permits formerly poor people to switch to rice from less prestigious staples such as millet and sweet potato.

Funded largely by the Bill & Melinda Gates Foundation, the C4 Rice Consortium is the world’s most ambitious genetic-engineering project. But the term genetic engineering does not capture the project’s scope. The genetic engineering that appears in news reports typically involves big companies sticking individual packets of genetic material, usually from a foreign species, into a crop. The paradigmatic example is Monsanto’s Roundup Ready soybean, which contains a snippet of DNA from a bacterium that was found in a Louisiana waste pond. That snippet makes the plant assemble a chemical compound in its leaves and stems that blocks the effects of Roundup, Monsanto’s widely used herbicide. The foreign gene lets farmers spray Roundup on their soy fields, killing weeds but leaving the crop unharmed. Except for making a single tasteless, odorless, nontoxic protein, Roundup Ready soybeans are otherwise identical to ordinary soybeans.

What the C4 Rice Consortium is trying to do with rice bears the same resemblance to typical genetically modified crops as a Boeing 787 does to a paper airplane. Rather than tinker with individual genes in order to monetize seeds, the scientists are trying to refashion photosynthesis, one of the most fundamental processes of life. Because C4 has evolved in so many different species, scientists believe that most plants must have precursor C4 genes. The hope is that rice is one of these, and that the consortium can identify and awaken its dormant C4 genes—following a path evolution has taken many times before. Ideally, researchers would switch on sleeping chunks of genetic material already in rice (or use very similar genes from related species that are close cousins but easier to work with) to create, in effect, a new and more productive species. Common rice, Oryza sativa, will become something else: Oryza nova, say. No company will profit from the result; the International Rice Research Institute, where much of the research takes place, will give away seeds for the modified grain, as it did with Green Revolution rice.

Directing the C4 Rice Consortium is Jane Langdale, a molecular geneticist at Oxford’s Department of Plant Sciences. Initial research, she told me, suggests that about a dozen genes play a major part in leaf structure, and perhaps another 10 genes have an equivalent role in the biochemistry. All must be activated in a way that does not affect the plant’s existing, desirable qualities and that allows the genes to coordinate their actions. The next, equally arduous step would be breeding rice varieties that can channel the extra growth provided by C4 photosynthesis into additional grains, rather than roots or stalk. All the while, varieties must be disease-resistant, easy to grow, and palatable for their intended audience, in Asia, Africa, and Latin America.

“I think it can all happen, but it might not,” Langdale said. She was quick to point out that even if C4 rice runs into insurmountable obstacles, it is not the only biological moonshot. Self-fertilizing maize, wheat that can grow in salt water, enhanced soil-microbial ecosystems—all are being researched. The odds that any one of these projects will succeed may be small, the idea goes, but the odds that all of them will fail are equally small. The Wizardly process begun by Borlaug is, in Langdale’s view, still going strong.

Summary

To Vogtians, the best agriculture takes care of the soil first and foremost, a goal that entails smaller patches of multiple crops—difficult to accomplish when concentrating on the mass production of a single crop. Truly extending agriculture that does this would require bringing back at least some of the people whose parents and grandparents left the countryside. Providing these workers with a decent living would drive up costs. Some labor-sparing mechanization is possible, but no small farmer I have spoken with thinks that it would be possible to shrink the labor force to the level seen in big industrial operations. The whole system can grow only with a wall-to-wall rewrite of the legal system that encourages the use of labor. Such large shifts in social arrangements are not easily accomplished.

And here is the origin of the decades-long dispute between Wizards and Prophets. Although the argument is couched in terms of calories per acre and ecosystem conservation, the disagreement at bottom is about the nature of agriculture—and, with it, the best form of society. To Borlaugians, farming is a kind of useful drudgery that should be eased and reduced as much as possible to maximize individual liberty. To Vogtians, agriculture is about maintaining a set of communities, ecological and human, that have cradled life since the first agricultural revolution, 10,000-plus years ago. It can be drudgery, but it is also work that reinforces the human connection to the Earth. The two arguments are like skew lines, not on the same plane.

My daughter is 19 now, a sophomore in college. In 2050, she will be middle-aged. It will be up to her generation to set up the institutions, laws, and customs that will provide for basic human needs in the world of 10 billion. Every generation decides the future, but the choices made by my children’s generation will resonate for as long as demographers can foresee. Wizard or Prophet? The choice will be less about what this generation thinks is feasible than what it thinks is good.

Feeding the World Requires Cutting-Edge Science and Institutions

 

Doomsday was predicted but failed to happen at midnight.

5 comments

  1. hunter · January 25, 2018

    Great catch, Ron. Thanks.
    So many NGOs are merely political action lobbying groups feasting on climate hype I no longer expect much old fashioned work out of them.
    It is pleasing to find out that some of them are still engaged in doing real work.
    The debate between those who wish to advance humanity and the pastoralists was settled, for me, years ago by the pastoralist Pol Pot and his Khmer Rouge.

    Like

    • Ron Clutz · January 25, 2018

      Thanks hunter. I had not seen that connection to the “killing fields.”

      Like

  2. nzrobin · January 25, 2018

    Thanks Ron, much new stuff in there for me, interesting and important. I enjoy reading your blog – and I wish you all the best for the year ahead.

    Like

    • Ron Clutz · January 25, 2018

      thanks robin, good luck with your bet, even though we all prefer a warmer world than a cold one.

      Like

  3. Hifast · January 27, 2018

    Reblogged this on Climate Collections.

    Like

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