This project aims to develop and test remote-sensing based approaches to gathering two typesof aid-relevant data: data on agricultural productivity and data on household assets, with a focus on Sub-Saharan Africa. The work will combine new high-resolution satellite imagery with household survey data to develop algorithms to measure crop yields and key household assets remotely (i.e. from space), with the household survey data providing the “ground truth” with which to train the algorithms.
Large-scale monitoring of crop growth and yield has important value for forecasting food production and prices and ensuring regional food security. A newly emerging satellite retrieval, solar-induced fluorescence (SIF) of chlorophyll, provides for the first time a direct measurement related to plant photosynthetic activity (i.e. electron transport rate). Here, we provide a framework to link SIF retrievals and crop yield, accounting for stoichiometry, photosynthetic pathways, and respiration losses. We apply this framework to estimate United States crop productivity for 2007–2012, where we use the spaceborne SIF retrievals from the Global Ozone Monitoring Experiment-2 satellite, benchmarked with county-level crop yield statistics, and compare it with various traditional crop monitoring approaches. We find that a SIF-based approach accounting for photosynthetic pathways (i.e. C3 and C4 crops) provides the best measure of crop productivity among these approaches, despite the fact that SIF sensors are not yet optimized for terrestrial applications. We further show that SIF provides the ability to infer the impacts of environmental stresses on autotrophic respiration and carbon-use-efficiency, with a substantial sensitivity of both to high temperatures. These results indicate new opportunities for improved mechanistic understanding of crop yield responses to climate variability and change.
A Stanford-led team has discovered how to estimate crop yields with more accuracy than ever before with satellites that measure a special form of light emitted by plants. This breakthrough will help scientists study how crops respond to climate change.
As Earth's population grows toward a projected 9 billion by 2050 and climate change puts growing pressure on the world's agriculture, researchers are turning to technology to help safeguard the global food supply.
A research team, led by Kaiyu Guan, a postdoctoral fellow in Earth system science at Stanford's School of Earth, Energy, & Environmental Sciences, has developed a method to estimate crop yields using satellites that can measure solar-induced fluorescence, a light emitted by growing plants. The team published its results in the journal Global Change Biology.
Scientists have used satellites to collect agricultural data since 1972, when the National Aeronautics and Space Administration (NASA) pioneered the practice of using the color – or "greenness" – of reflected sunlight to map plant cover over the entire globe.
"This was an amazing breakthrough that fundamentally changed the way we view our planet," said Joe Berry, professor of global ecology at the Carnegie Institution for Science and a co-author of the study. "However, these vegetation maps are not ideal predictors of crop productivity. What we need to know is growth rate rather than greenness.
The growth rate can tell researchers what size yield to expect from crops by the end of the growing season. The higher the growth rate of a soybean plant or stalk of corn, for instance, the greater the harvest from a mature plant.
"What we need to measure is flux – the carbon dioxide that is exchanged between plants and the atmosphere – to understand photosynthesis and plant growth," Guan said. "How do you use color to infer flux? That's a big gap."
Solar-induced fluorescence
Recently, researchers at NASA and several European institutes discovered how to measure this flux, called solar-induced fluorescence, from satellites that were originally designed for measuring ozone and other gases in the atmosphere.
A plant uses most of the energy it absorbs from the sun to grow via photosynthesis, and dissipates unused energy as heat. It also passively releases between 1 and 2 percent of the original solar energy absorbed by the plant back into the atmosphere as fluorescent light. Guan's team worked out how to distinguish the tiny flow of specific fluorescence from the abundance of reflected sunlight that also arrives at the satellite.
"I think of it like crumbs falling to the ground as people are eating. It's a very small trail," said co-author David Lobell, associate professor of Earth system science at Stanford's School of Earth, Energy, & Environmental Science. "This glow that plants have seems to be very proportional to how fast they're growing. So the more they're growing, the more photosynthesis they're doing, and the brighter they're fluorescing." Lobell is also deputy director of the Center on Food Security and the Environment.
The research team saw an opportunity to use this new data to close the knowledge gap about crop growth, beginning with a major corn- and soybean-producing region of the U.S. Midwest.
"With the fluorescence breakthrough, we can start to directly measure photosynthesis instead of color," Guan said.
The fact that fluorescence can now be detected from space allows researchers to measure plant growth across much larger areas and over long periods of time, giving a much clearer picture of how yields fluctuate under changing weather conditions.
"One of the really cool things about fluorescence is that it opens up a whole new set of questions that we can ask about vegetation, and often times it's these new measurements that drive the science forward," Lobell said.
Next steps
The research team has already identified a number of potential uses of this approach by agricultural scientists, farmers, crop insurance providers and government agencies concerned with agricultural productivity.
If there is a day when the plant is really stressed, the fluorescence will drop significantly, Lobell said. Capturing these short-term responses to environmental changes will help scientists understand what factors plants are responding to on the daily time scale.
"That helps us, for example, figure out what we need to worry about in terms of stresses that crops are responding to," Lobell said. "What should we really be focusing on in terms of the next generation of cropping systems? What should they be able to withstand that the current crops can't withstand?"
At this early stage, fluorescence measurements are relatively low-resolution (a single measurement covers about 50 square kilometers) and because it is only collected once per day, cloudy skies can interfere with the fluorescence signal. For now, researchers have to supplement the data with other information and with on-the-ground observations to refine the measurements.
"Now that we have demonstrated the concept, we hope to soon be orbiting some new satellites specifically designed to make fluorescence measurements with better spatial and temporal resolution," Berry said.
The team plans to continue its research on U.S. crop yields while expanding measurements to other parts of the world.
"In the future, we hope to directly use this technology to monitor global food production, for example in China or Brazil, or even in your backyard," Guan said.
David Lobell is also deputy director of the Center on Food Security and the Environment, and William Wrigley Senior Fellow at the Freeman Spogli Institute for International Studies and the Stanford Woods Institute for the Environment. The study was also co-authored by Youngguan Zhang of the International Institute for Earth System Sciences at Nanjing University and the German Research Center for Geosciences (GFZ); Joanna Joiner of the NASA Goddard Space Flight Center Laboratory for Atmospheric Chemistry and Dynamics; Luis Guanter of GFZ; and Grayson Badgley of Stanford's Department of Earth System Science and Department of Global Ecology at the Carnegie Institution for Science.
CONTACTS:
p> Kaiyu Guan, Stanford School of Earth, Energy, & Environmental Sciences: kaiyug@stanford.edu
Laura Seaman, Stanford's Center on Food Security and the Environment: lseaman@stanford.edu, (650) 723-4920
Governments must do more to diversify the types of crops grown throughout the world. If they don’t, climate change may jeopardize the global food supply, a leading agriculture researcher told a Stanford audience.
Cary Fowler, a senior advisor and former executive director of the Global Crop Diversity Trust, was a driving force behind the creation of the Svalbard Global Seed Vault in Norway. Commonly known as the “doomsday vault,” the repository of ancient and modern seeds from around the world ensures that future generations will have access to a wide enough range of crop traits to adapt global agriculture to a changing climate.
Dr. Cary Fowler in Svalbard, Norway, the home of the Svalbard Global Seed Vault.
During a May 6 talk sponsored by FSE as part of the center’s Food and Nutrition Policy Symposium, Fowler warned that increasingly high temperatures and water shortages interfere with the natural growing cycles of many crops and can even reduce the nutritional quality of some plants. Higher temperatures also give way to new pests, diseases, and soil microorganisms that threaten yields.
“The biggest impacts from climate change will be in sub-Saharan Africa,” Fowler said, a region where many people already suffer serious poverty and hunger, and where crop yields lag behind the rest of the world. Fowler said that as climate pressure on agriculture intensifies, the world can expect to see an uptick in civil conflict, restrictive trade policies, and suffering among the world’s poorest people.
“Crops are going to be facing new combinations of conditions for which there is no historical experience,” said Fowler. “They will require new combinations of traits” that can only be developed by preserving genetic diversity and proactively breeding new varieties.
“There are 1.3 billion people living on subsistence farms today,” said Dr. Cary Fowler to a Stanford audience on May 6. “How will they adapt to climate change without access to diversity?”
Fowler called for the U.S. and foreign governments to embrace their “inherited evolutionary responsibility” for preserving the huge diversity of crops grown by farmers throughout human history.
The United States is the ideal candidate to lead the world in using crop genetic diversity to adapt agriculture to climate challenges, he said. “The U.S. is well-positioned to research diversity, model future climate and assemble seed packages,” enlisting farmers in the U.S. and abroad in “another mass adaptation experiment” like the one American agriculture undertook in the 18th and 19th centuries.
“I know that sounds like a wild and crazy idea,” Fowler said. “But I haven’t heard any alternatives to it. If we’re assuming we’re going to have development without diversity, that would really be a historically unprecedented experiment.”
“If agriculture doesn’t adapt,” he added, “neither will we.”
A diverse history
In the late 1700s the United States food system lacked diversity and infrastructure. “Very few of the crops we grow now in the U.S. are native,” said Fowler. Early on, “it wasn’t always evident what crops from abroad would grow well in the U.S.”
The government soon set out to expand and diversify American agriculture. U.S. Navy ships collected seeds on overseas voyages, and U.S. diplomats brought back new crops from postings abroad. Government-sponsored expeditions sought out foreign plants with specific disease-resistant traits. The U.S. signed two dozen seed-exchange agreements with other countries, and lowered taxes on imported seeds to boost global crop exchange.
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“The United States amassed a much more diverse array of seeds and crops as a result,” said Fowler. One program introduced 600 new apple varieties, 700 new types of pears, and 353 new varieties of mangoes to American farmers.
But the United States did not simply collect new crops. It also invested in research to develop new varieties, including through plant breeding.
Genetic erosion
Research into plant breeding quickly yielded many of the modern varieties of crops we grow today in the United States.
“With plant breeding came the rise of modern varieties that had useful traits like disease resistance,” said Fowler. A small handful of new varieties quickly gained popularity with American farmers, who now had a choice about whether or not to save seeds and grow many varieties of a crop at once. Most farmers chose not to, instead relying on the same few mainstream varieties their neighbors were growing.
This shift has led to what Fowler described as the “genetic erosion” of agriculture, a trend that can only be reversed by reviving the tradition of seed saving and plant breeding on a global scale.
Seed banks
“I have probably been to more seed banks than any other person,” said Fowler. Seeds from most crops can survive hundreds or even thousands of years in storage, but most storage facilities lack the physical security to provide lasting safe haven. Many seed banks are poorly built, too warm or humid for long-term storage, and vulnerable to natural disasters. Other facilities suffer damaged during civil wars and uprisings.
Even if banks are physically secure, said Fowler, most simply do not operate on a large enough scale to protect global crop diversity. “Most crops in the world have between one and 10 total seed samples in storage, and most have no plant breeders working on them at all,” said Fowler.
The doomsday vault
In 2005 Fowler was chosen to lead an international coalition to build the Svalbard Global Seed Vault. The Norwegian government owns the facility, and it is also managed by the Global Crop Diversity Trust and the Nordic Genetic Resource Center.
The vault is built into the side of a mountain in the far north of Norway, said Fowler, because the ideal temperature for storing seeds is minus 18 degrees Celsius.
Inside the frozen walls of the vault are shelves full of boxes holding duplicate seeds from smaller seed banks around the world. Foreign governments that contribute samples pay nothing for storage, and the seed packages are never opened by vault staff, said Fowler.
“The vault now houses seeds from over 864,000 varieties of plants,” said Fowler, adding that not a single sample has ever been lost.
Seed storage boxes at the Svalbard Global Seed Vault.
The facility’s nickname, “the doomsday vault,” comes not only from its rugged physical location but from its capacity to withstand disasters – something its planners took great care to design. “We calculated how high the water would go if all ice in the world melted and we had the world’s largest ever tsunami,” said Fowler. “The vault is five stories above that.”
“Not a solution”
Fowler emphasized that no doomsday vault, no matter how secure its walls or how ample its seed collection, can solve the problem of crop genetic erosion. Building a vault “doesn’t mean that we as a society are getting serious about adapting agriculture to climate change,” Fowler said. Plant breeding and crop research programs focused on developing new climate-resilient varieties are just as crucial as saving seeds.
Although a few major staple crops like rice, wheat and corn are continually bred and improved in research labs around the world, most crops are largely ignored by researchers. For example, there are only six breeders of yams worldwide.
“Why conserve it if you’re not going to use it?” Fowler asked. “We are acting like crops are going to adapt by themselves, and we are assuming all but a handful of crops are unimportant.”
Quoting Charles Darwin, Fowler added that “it is not the strongest of the species that survives, nor the most intelligent, but the one most responsive to change.”
Full video and audio recordings of Dr. Fowler's May 6 lecture, and his interview with FSE director Roz Naylor, are available here.
Lobell's research focuses on identifying opportunities to raise crop yields in major agricultural regions, with a particular emphasis on adaptation to climate change. His current projects span Africa, South Asia, Mexico, and the United States, and involve a range of tools including remote sensing, GIS, and crop and climate models.
"David Lobell's research on climate change and food security is truly global in scope, but his work also crosses academic borders," said FSI director Mike McFaul. "David's appointment as William Wrigley Senior Fellow recognizes his ability to connect the most pressing challenges in international development with critical questions of environmental sustainability, in a way that generates real solutions on both fronts."
The William Wrigley Senior Fellowship is supported by Mrs. Julie Ann Wrigley, AB '71 (Anthropology) and Ms. Alison Wrigley Rusack, AB '80 (Communication).
"The Wrigley fellowship recognizes the important contributions of our faculty to ensuring a sustainable world and is one family’s remarkable legacy to reshape the future of the environment on which we all depend," said Perry L. McCarty Director Barton "Buzz" Thompson, who co-leads the Stanford Woods Institute with Perry L. McCarty Director Jeffrey Koseff. "Both David and the first holder of the fellowship, Roz Naylor, are leaders in the effort to provide food security to the planet's growing population, perhaps the most critical challenge the world faces."
"David's work already transcends disciplines and departments through his work with the Center on Food Security and the Environment, a synergistic partnership between Woods and the Freeman Spogli Institute," Koseff added. "The Wrigley fellowship provides important support for this type of collaborative, cross-cutting research at Stanford."
Lobell was a Senior Research Scholar at the Center on Food Security and the Environment from 2008-2009 and a Lawrence Post-doctoral Fellow at Lawrence Livermore National Laboratory from 2005-2007. He received a PhD in Geological and Environmental Sciences from Stanford University in 2005, and a Sc.B. in Applied Mathematics, Magna Cum Laude from Brown University in 2000.
Each year Stanford experts from a range of disciplines meet to discuss the interconnections and interactions among humanity's needs for and use of food, energy, water and the effect they have on climate and conflict. These experts will illustrate and evaluate some of the ways in which decisions in one resource area can lead to trade-offs or co-benefits in others, and discuss opportunities to make decisions that can have positive benefits in one area while avoiding negative or unintended consequences in other areas. This year, in celebration of our 5th anniversary of Connecting the Dots, we return to the food nexus.
Confirmed Speakers
Keynote Speaker: Karen Ross, Secretary of California Department of Food and Agriculture
Professor Stacey Bent, TomKat Center for Sustainable Energy, Precourt Institute for Energy, Chemical Engineering
Professor Roz Naylor, Center on Food Security and the Environment, Environmental Earth System Science, Stanford Woods Institute for the Environment, Freeman Spogli Institute for International Studies
Professor David Lobell, Center on Food Security and the Environment, Environmental Earth System Science, Freeman Spogli Institute for International Studies, Stanford Woods Institute for the Environment
Professor Marshall Burke (food - conflict nexus), Environmental Earth System Science, Center on Food Security and the Environment
Professor Steve Luby (food - health nexus), Stanford Medicine, Stanford Woods Institute for the Environment, Freeman Spogli Institue for International Studies
Professor Scott Rozelle (food, education and development nexus), Co-director, Rural Education Action Program, Freeman Spogli Institute for International Studies, Stanford Institute for Economic Policy Research, Center on Food Security and the Environment
Student-led Breakout Sessions
Christopher Seifert, Graduate Student, Environmental Earth System Science "Boondoggle or Risk Reducer? Crop insurance as the farm subsidy of the 21st century"
William Chapman, Graduate Student, CEE-Atmosphere and Energy "No Red Meat or a New Electric Vehicle, Food Choices and Emissions"
Priya Fielding-Singh, PhD Candidate, Sociology Maria Deloso, Coterminal B.S/M.A. Candidate, Environmental Earth System Science "From Farm to Lunch Tray: Toward a Healthy and Sustainable Federal School Lunch Program"
Rebecca Gilsdorf, PhD Candidate, Civil & Environmental Engineering Angela Harris, PhD Candidate, Civil & Environmental Engineering "Poop and Pesticides: Looking beyond production to consider food contamination"
George Azzari joined FSE as a Postdoctoral Research Scholar in February 2015. He worked with David Lobell on designing, implementing, and applying new satellite-based monitoring techniques to study several aspects of food security. His current focuses include estimates of crop yields, crop classification, and detection of management practices in Africa, Asia, and the United States. He is currently the Chief Technology Office at Atlas AI.
George's research uses a variety of satellite sensors from the private and public sector -including Landsat (NASA/USGS), Sentinel 1 and 2 (ESA), MODIS (NASA), RapidEye (Planet), Planet Scope (Planet), and Skysat (Terrabella)- combined with crop modeling and machine learning techniques. He received his Ph.D. from the University of California, Irvine, where he worked with Mike Goulden on monitoring post-fire succession of southern California ecosystems from remote sensing data. He examined the impact of topographic illumination effects on long time series of optical satellite data.
For 14 years, Mariano-Florentino Cuéllar has been a tireless Stanford professor who has strengthened the fabric of university’s interdisciplinary nature. Joining the faculty at Stanford Law School in 2001, Cuéllar soon found a second home for himself at the Freeman Spogli for International Studies. He held various leadership roles throughout the institute for several years – including serving as co-director of the Center for International Security and Cooperation. He took the helm of FSI as the institute’s director in 2013, and oversaw a tremendous expansion of faculty, research activity and student engagement.
An expert in administrative law, criminal law, international law, and executive power and legislation, Cuéllar is now taking on a new role. He leaves Stanford this month to serve as justice of the California Supreme Court and will be succeeded at FSI by Michael McFaul on Jan. 5.
As the academic quarter comes to a close, Cuéllar took some time to discuss his achievements at FSI and the institute’s role on campus. And his 2014 Annual Letter and Report can be read here.
You’ve had an active 20 months as FSI’s director. But what do you feel are your major accomplishments?
We started with a superb faculty and made it even stronger. We hired six new faculty members in areas ranging from health and drug policy to nuclear security to governance. We also strengthened our capacity to generate rigorous research on key global issues, including nuclear security, global poverty, cybersecurity, and health policy. Second, we developed our focus on teaching and education. Our new International Policy Implementation Lab brings faculty and students together to work on applied projects, like reducing air pollution in Bangladesh, and improving opportunities for rural schoolchildren in China. We renewed FSI's focus on the Ford Dorsey Program in International Policy Studies, adding faculty and fellowships, and launched a new Stanford Global Student Fellows program to give Stanford students global experiences through research opportunities. Third, we bolstered FSI's core infrastructure to support research and education, by improving the Institute's financial position and moving forward with plans to enhance the Encina complex that houses FSI.
Finally, we forged strong partnerships with critical allies across campus. The Graduate School of Business is our partner on a campus-wide Global Development and Poverty Initiative supporting new research to mitigate global poverty. We've also worked with the Law School and the School of Engineering to help launch the new Stanford Cyber Initiative with $15 million in funding from the Hewlett Foundation. We are engaging more faculty with new health policy working groups launched with the School of Medicine and an international and comparative education venture with the Graduate School of Education.
Those partnerships speak very strongly to the interdisciplinary nature of Stanford and FSI. How do these relationships reflect FSI's goals?
The genius of Stanford has been its investment in interdisciplinary institutions. FSI is one of the largest. We should be judged not only by what we do within our four walls, but by what activity we catalyze and support across campus. With the business school, we've launched the initiative to support research on global poverty across the university. This is a part of the SEED initiative of the business school and it is very complementary to our priorities on researching and understanding global poverty and how to alleviate. It's brought together researchers from the business school, from FSI, from the medical school, and from the economics department.
Another example would be our health policy working groups with the School of Medicine. Here, we're leveraging FSI’s Center for Health Policy, which is a great joint venture and allows us to convene people who are interested in the implementation of healthcare reforms and compare the perspective and on why lifesaving interventions are not implemented in developing countries and how we can better manage biosecurity risks. These working groups are a forum for people to understand each other's research agendas, to collaborate on seeking funding and to engage students.
I could tell a similar story about our Mexico Initiative. We organize these groups so that they cut across generations of scholars so that they engage people who are experienced researchers but also new fellows, who are developing their own agenda for their careers. Sometimes it takes resources, sometimes it takes the engagement of people, but often what we've found at FSI is that by working together with some of our partners across the university, we have a more lasting impact.
Looking at a growing spectrum of global challenges, where would you like to see FSI increase its attention?
FSI's faculty, students, staff, and space represent a unique resource to engage Stanford in taking on challenges like global hunger, infectious disease, forced migration, and weak institutions. The key breakthrough for FSI has been growing from its roots in international relations, geopolitics, and security to focusing on shared global challenges, of which four are at the core of our work: security, governance, international development, and health.
These issues cross borders. They are not the concern of any one country.
Geopolitics remain important to the institute, and some critical and important work is going on at the Center for International Security and Cooperation to help us manage the threat of nuclear proliferation, for example. But even nuclear proliferation is an example of how the transnational issues cut across the international divide. Norms about law, the capacity of transnational criminal networks, smuggling rings, the use of information technology, cybersecurity threats – all of these factors can affect even a traditional geopolitical issue like nuclear proliferation.
So I can see a research and education agenda focused on evolving transnational pressures that will affect humanity in years to come. How a child fares when she is growing up in Africa will depend at least as much on these shared global challenges involving hunger and poverty, health, security, the role of information technology and humanity as they will on traditional relations between governments, for instance.
What are some concrete achievements that demonstrate how FSI has helped create an environment for policy decisions to be better understood and implemented?
We forged a productive collaboration with the U.N. High Commissioner for Refugees through a project on refugee settlements that convened architects, Stanford researchers, students and experienced humanitarian responders to improve the design of settlements that house refugees and are supposed to meet their human needs. That is now an ongoing effort at the UN Refugee Agency, which has also benefited from collaboration with us on data visualization and internship for Stanford students.
Our faculty and fellows continue the Institute's longstanding research to improve security and educate policymakers. We sometimes play a role in Track II diplomacy on sensitive issues involving global security – including in South Asia and Northeast Asia. Together with Hoover, We convened a first-ever cyber bootcamp to help legislative staff understand the Internet and its vulnerabilities. We have researchers who are in regular contact with policymakers working on understanding how governance failures can affect the world's ability to meet pressing health challenges, including infectious diseases, such as Ebola.
On issues of economic policy and development, our faculty convened a summit of Japanese prefectural officials work with the private sector to understand strategies to develop the Japanese economy.
And we continued educating the next generation of leaders on global issues through the Draper Hills summer fellows program and our honors programs in security and in democracy and the rule of law.
How do you see FSI’s role as one of Stanford’s independent laboratories?
It's important to recognize that FSI's growth comes at particularly interesting time in the history of higher education – where universities are under pressure, where the question of how best to advance human knowledge is a very hotly debated question, where universities are diverging from each other in some ways and where we all have to ask ourselves how best to be faithful to our mission but to innovate. And in that respect, FSI is a laboratory. It is an experimental venture that can help us to understand how a university like Stanford can organize itself to advance the mission of many units, that's the partnership point, but to do so in a somewhat different way with a deep engagement to practicality and to the current challenges facing the world without abandoning a similarly deep commitment to theory, empirical investigation, and rigorous scholarship.
What have you learned from your time at Stanford and as director of FSI that will inform and influence how you approach your role on the state’s highest court?
Universities play an essential role in human wellbeing because they help us advance knowledge and prepare leaders for a difficult world. To do this, universities need to be islands of integrity, they need to be engaged enough with the outside world to understand it but removed enough from it to keep to the special rules that are necessary to advance the university's mission.
Some of these challenges are also reflected in the role of courts. They also need to be islands of integrity in a tumultuous world, and they require fidelity to high standards to protect the rights of the public and to implement laws fairly and equally.
This takes constant vigilance, commitment to principle, and a practical understanding of how the world works. It takes a combination of humility and determination. It requires listening carefully, it requires being decisive and it requires understanding that when it's part of a journey that allows for discovery but also requires deep understanding of the past.
Dr. Cary Fowler in Svalbard, Norway, the home of the Svalbard Global Seed Vault.
Seed storage boxes at the Svalbard Global Seed Vault.
