In a recent speech, Stanford professor Rosamond Naylor examined the wide range of challenges contributing to global food insecurity, which Naylor defined as a lack of plentiful, nutritious and affordable food. Naylor's lecture, titled "Feeding the World in the 21st Century," was part of the quarterly Earth Matters series sponsored by Stanford Continuing Studies and the Stanford School of Earth Sciences. Naylor, a professor of Environmental Earth System Science and director of the Center on Food Security and the Environment at Stanford, is also a professor (by courtesy) of Economics, and the William Wrigley Senior Fellow at the Freeman Spogli Institute for International Studies and the Stanford Woods Institute for the Environment.

"One billion people go to bed day in and day out with chronic hunger," said Naylor. The problem of food insecurity, she explained, goes far beyond food supply. "We produce enough calories, just with cereal crops alone, to feed everyone on the planet," she said. Rather, food insecurity arises from a complex and interactive set of factors including poverty, malnutrition, disease, conflict, poor governance and volatile prices. Food supply depends on limited natural resources including water and energy, and food accessibility depends on government policies about land rights, biofuels, and food subsidies. Often, said Naylor, food policies in one country can impact food security in other parts of the world. Solutions to global hunger must account for this complexity, and for the "evolving" nature of food security.

As an example of this evolution, Naylor pointed to the success of China and India in reducing hunger rates from 70 percent to 15 percent within a single generation. Economic growth was key, as was the "Green Revolution," a series of advances in plant breeding, irrigation and agricultural technology that led to a doubling of global cereal crop production between 1970 and 2010. But Naylor warned that the success of the Green Revolution can lead to complacency about present-day food security challenges. China, for example, sharply reduced hunger as it underwent rapid economic growth, but now faces what Naylor described as a "second food security challenge" of micronutrient deficiency. Anemia, which is caused by a lack of dietary iron and which Naylor said is common in many rural areas of China, can permanently damage children's cognitive development and school performance, and eventually impede a country’s economic growth.

Hunger knows no boundaries

Although hunger is more prevalent in the developing world, food insecurity knows no geographic boundaries, said Naylor. Every country, including wealthy economies like the United States, struggles with problems of food availability, access, and nutrition. "Rather than think of this as 'their problem' that we don't need to deal with, really it's our problem too," Naylor said.

She pointed out that one in five children in the United States is chronically hungry, and 50 million Americans receive government food assistance. Many more millions go to soup kitchens every night, she added. "We are in a precarious position with our own food security, with big implications for public health and educational attainment," Naylor said. A major paradox of the United States' food security challenge is that hunger increasingly coexists with obesity. For the poorest Americans, cheap food offers abundant calories but low nutritional value. To improve the health and food security of millions of Americans, "linking policy in a way that can enhance the incomes of the poorest is really important, and it's the hard part,” she said.” It's not easy to fix the inequality issue."

Success stories

When asked whether there were any "easy" decisions that the global community can agree to, Naylor responded, "What we need to do for a lot of these issues is pretty clear, but how we get after it is not always agreed upon." She added, "But I think we've seen quite a few success stories," including the growing research on climate resilient crops, new scientific tools such as plant genetics, improved modeling techniques for water and irrigation systems, and better knowledge about how to use fertilizer more efficiently. She also said that the growing body of agriculture-focused climate research was encouraging, and that Stanford is a leader on this front.

Naylor is the editor and co-author of The Evolving Sphere of Food Security, a new book from Oxford University Press. The book features a team of 19 faculty authors from 5 Stanford schools including Earth science, economics, law, engineering, medicine, political science, international relations, and biology. The all-Stanford lineup was intentional, Naylor said, because the university is committed to interdisciplinary research that addresses complex global issues like food security, and because "agriculture is incredibly dominated by policy, and Stanford has a long history of dealing with some of these policy elements. This is the glue that enables us to answer really challenging questions." 

Hunger touches the lives of people throughout the world, from the affluent Bay Area to the most impoverished regions of rural Africa. Food security – the availability of plentiful, nutritious, and affordable food – is a pressing issue for rich and poor countries alike as the world population moves toward 9 billion by mid-century.

In her new book The Evolving Sphere of Food Security (Oxford University Press, August), Professor Rosamond Naylor takes a holistic approach to the question of how to feed the world. Naylor, a professor of environmental earth system science and director of the Center on Food Security and the Environment (FSE), convened 18 colleagues from across Stanford’s diverse disciplines to shed light on the interdependent issues that affect global food security.

Throughout its 14 chapters, and a foreword by former United Nations Secretary-General Kofi Annan, the book takes up two important questions: How does the challenge of achieving food security change as countries develop economically? And how do food and agriculture policies in one country affect nutrition, food access, natural resources and national security in other countries?

Collaboration across disciplines

Naylor, who edited the volume and co-authored several chapters, explained that The Evolving Sphere of Food Security is the first book of its kind to engage faculty and scholars from across Stanford’s campus on issues of global hunger.

Professor Rosamond Naylor

“This book grew out of a recognition by Stanford scholars that food security is tied to security of many other kinds,” said Naylor, who is also William Wrigley Senior Fellow at the Freeman Spogli Institute for International Studies and the Stanford Woods Institute for the Environment. “Food security has clear connections with energy, water, health, the environment and national security, and you can’t tackle just one of those pieces.”

Stanford has a long history of fostering cross-disciplinary work on global issues. It is in this spirit that the idea for the book was born, Naylor said. The book weaves together the expertise of authors from the fields of medicine, political science, engineering, law, economics and climate science.

“Stanford was the ideal place for this project. A book like this exemplifies how collaborative, interdisciplinary research can be greater than the sum of its parts,” Naylor said. “We have painted a much more inclusive picture of food security than if we had approached these questions from only one discipline.”

Rooted in field research

Another unique feature of the book is that each author’s insights are shaped by years of hands-on research and policymaking experience around the world.

Several authors, for example, have been instrumental in shaping U.S. and global food policy for decades. Walter Falcon, professor emeritus of economics and the deputy director of FSE, traces his career as an agricultural economics advisor to the Indonesian government, where he witnessed the country’s dramatic improvements in combating hunger and poverty since the 1960s.

Political science professor Stephen Stedman recounts his experience as a security policy advisor to the United Nations during the 2000s. Recognizing that food insecurity can exacerbate civil conflict, weaken governments and threaten international stability, Stedman worked to integrate food security into traditional security agendas.

Other authors have spent many years working in East Asia, Africa, South America, the Middle East and Europe. As a whole, said Naylor, the team has conducted well over a hundred years’ worth of field research all over the world.

Challenges evolve as countries develop

A recurring theme throughout the book – also reflected in its title – is the evolving nature of the food security challenges countries face as they move through stages of economic growth. At low levels of development, countries struggle to meet people’s basic needs. For example, Naylor’s chapter on health, co-authored with Eran Bendavid (medicine), Jenna Davis and Amy Pickering (civil and environmental engineering), describes a recent study showing that poor nutrition and rampant disease in rural Kenya is closely tied to contaminated, untreated drinking water. Addressing these essential health and sanitation issues is a key first step toward food security for the poorest countries.

As nations rise above the bottom rungs of development, they encounter new challenges. Scott Rozelle, director of the Rural Education Action Program, warns that middle income countries like China now face a “second food security crisis” of widespread micronutrient deficiency. Recent rapid economic and agricultural advancements have largely solved the problem of supplying sufficient calories. But this progress masks what Rozelle describes as “hidden hunger,” or a lack of vitamins and minerals that impedes kids’ school performance and could slow China’s long-term growth. Even in rich countries like the U.S., said Naylor, malnutrition can be a drag on educational and economic performance.

Developed countries face other unique tradeoffs in the use of resources for food production. In his chapter on water institutions, Buzz Thompson, professor of law and co-director of the Woods Institute, explains that conflicts over water increase between smallholder and industrial users as countries develop. Eric Lambin, professor of environmental earth system science, and Ximena Rueda, research associate in earth sciences, offer the paradox that as countries grow wealthier, changing patterns of agricultural land use may actually worsen food security by fueling the spread of obesity and diabetes.

At its core, said Naylor, The Evolving Sphere of Food Security is about more than economic and policy trends. “The book puts a human face to food security, because hunger is an intensely human experience,” she said. “This book tells an integrated story about people’s lives, and how they are shaped by resource use and the policy process around global food security.”

According to a new study co-authored by Stanford professor David Lobell, the chance of a worldwide slowdown in agricultural yield growth in the next two decades is significantly higher due to global warming.

Lobell and co-author Claudia Tebaldi, a senior researcher at the National Center for Atmospheric Research, set out to estimate the odds of a steep drop in global wheat and corn yield progress under several climate scenarios. The study, “Getting caught with our plants down: the risks of a global crop yield slowdown from climate trends in the next two decades” appeared in Environmental Research Letters.

Lobell said he was motivated to pursue the study based on questions posed by stakeholders and decision makers in governments and the private sector.

“I’m often asked whether climate change will threaten food supply, as if it’s a simple yes or no answer,” Lobell said. “The truth is that over a 10 or 20 year period, it depends largely on how fast the Earth warms, and we can’t predict that very precisely. So the best we can do is try to determine the odds.”

Lobell and Tebaldi calculated the chance of a 10 percent global yield loss from climate change over the next 20 years, which would represent a severe impact on food supply, enough to roughly halve the rate of yield growth.

The short time frame of the study was deliberate, Lobell said. “Many studies have looked at climate and agriculture trends over the coming 50 or 100 years. But the next two decades are when most of the global population growth, and dietary shifts driven by a growing middle class, will occur. The growth rate of food demand will be higher during this time than at any other time in the next century.”

Without human-induced global warming – in other words, in a world with only natural climate variability – the likelihood of a yield drop that large is only 1 in 200. But when the team accounted for global warming, they saw the odds jump to 1 in 10 for corn and 1 in 20 for wheat. “In this study, we did not try to estimate the most likely impacts of climate change on crops,” Lobell said. “Rather, we estimated the likelihood of a really major impact, not because we want to scare people, but because there are many people who want to be prepared for all contingencies.”

“The point of the paper is to move from hand-waving about scenarios of what could go wrong, to specific and transparent estimates of the actual odds,” Lobell said. “The odds are not very high, but they are significant and a lot bigger than they used to be. The people asking these questions are accustomed to planning for scenarios with much less than a 10 percent chance of happening, so it will be interesting to see whether this study has any effect on how they operate.”

Lobell adds that organizations working toward global food security, and related issues such as conflict prevention, are most interested in the next 20 years because their decisions rarely consider the more distant future.  “As scientists, we might prefer to work on time scales in which the answers are clearer, but we also want to be responsive to the actual concerns and questions that decision makers have.”

Lobell is associate professor of Environmental Earth System Science at Stanford and associate director of the Center on Food Security and the Environment. He is also a senior fellow at the Stanford Woods Institute for the Environment and the Freeman Spogli Institute for International Studies.

Contact:

David Lobell: dlobell@stanford.edu

Laura Seaman, Communications and External Relations Manager, Center on Food Security and the Environment: lseaman@stanford.edu

New research from Stanford scientists shows that farmers in Europe will see crop yields affected as global temperatures rise, but that adaptation can help slow the decline for some crops.

A new study by Stanford Ph.D. student Frances Moore and professor David Lobell finds that with the average 3.5 degrees Fahrenheit of warming expected by 2040, yields of wheat and barley across Europe are expected to be more than 20% lower than they would be without warming.  For corn, the loss is roughly 10% less than without warming. Farmers of these crops have already seen yield growth slow down since 1980 as temperatures have risen, although other policy and economic factors have also played a role.

 ”The results clearly showed that modest amounts of climate change can have a big impact on yields of several crops in Europe,” said Moore, a Ph.D. student in the Emmett Interdisciplinary Program in Environment and Resources at Stanford. “This is a little surprising because the region is fairly cool, so you might think it would benefit from moderate amounts of warming. Our next step was to actually measure the potential of European farmers to adapt to these impacts."

Moore and Lobell analyzed yield and profit records from thousands of farms between 1989 and 2009, from the European Union's annual Farmer Accountancy Data Network survey. Combining detailed climate records with the farm data, they were able to understand how yields and profits have changed over time. By comparing yields in warmer and cooler parts of Europe, they could predict how adaptation may help European farmers in the coming decades.

“By adaptation, we mean a range of options based on existing technologies, such as switching varieties of a crop, installing irrigation, or growing a different crop to one better suited to warmer temperatures” said Lobell, associate professor of Environmental Earth System Science and the associate director of the Center on Food Security and the Environment at Stanford. “These things have been talked about for a long time, but the novelty of this study was using past data to quantify the actual potential of adaptation to reduce climate change impacts. We find that in some cases adaptation could substantially reduce impacts, but in other cases the potential may be very limited with current technologies.”

According to the new analysis, corn has the highest adaptation potential. Moore and Lobell predict that corn farmers can reduce yield losses by as much as 87% through long-term adaptation. 

As Moore points out, three key areas of uncertainty make it difficult to predict the future of crop yields in Europe. Most scientists focus on the uncertainty around future climate conditions, but the Stanford team found that the biggest issue is often how quickly farmers in Europe will adapt to climate change (adaptation uncertainty), and how crop yields will respond to climate change (response uncertainty).

In future research, Moore and Lobell hope to focus on measuring how quickly farmers are adapting to changing temperatures.  

“This paper has shown that crops in Europe are sensitive to warming and that adaptation can be important in reducing that impact,” said Moore. “The next question is how quickly farmers will use the available options for adapting. Europe has already seen a lot of warming, so we should expect to already see adaptation if farmers are quick to respond to climate signals.”

The full study is available from Nature Climate Change. 

Laura Seaman is the Communications and External Relations Manager at the Center on Food Security and the Environment, a joint initiative of the Freeman Spogli Institute for International Studies and the Woods Institute for the Environment at Stanford University. 

FSE’s David Lobell finds that an increase of more than two degrees Celsius in average global temperature is likely to cause yields of wheat, rice and maize to fall throughout the 21st century. Early adaptation could increase projected yields by up to 15 percent.

If global temperatures continue to rise, the amount of crops farmers can harvest will sharply decline during the next 100 years.

Stanford professor David Lobell and an international team of climate scientists modeled future crop yields under several global climate scenarios throughout the 21^st century. They found that if average global temperatures rise by more than two degrees Celsius, farmers are likely to get less wheat, rice and maize out of each plot of land. Yields are expected to fall by an average of 4.9 percent for every one degree Celsius rise in average temperature. Year-to-year variability of harvests is also expected to rise, as drought and flooding become more frequent. Crop yield losses will speed up throughout the century, with declines in yield beginning around 2030 and with the fastest drop happening in the second half of the century.

Lobell, an associate professor of Environmental Earth System Science and the associate director of the Center on Food Security and the Environment at Stanford, reviewed over 1,700 published studies with a team of climate scientists from the United States, United Kingdom and Australia. The team found that if farmers adapt to climate change within the next few years, they have a better chance of avoiding or even reversing the predicted decline of wheat and rice yields in some regions. Agricultural adaptation strategies like irrigating fields and developing new crop breeds could increase projected yields between 7 percent and 15 percent.

The new study also highlights the need for better data on the potential future impacts of other factors that affect crop yields, like the prevalence of pests and plant diseases, and the availability of water supply. A full version of the study can be found online at Nature Climate Change.