FSI scholars approach their research on the environment from regulatory, economic and societal angles. The Center on Food Security and the Environment weighs the connection between climate change and agriculture; the impact of biofuel expansion on land and food supply; how to increase crop yields without expanding agricultural lands; and the trends in aquaculture. FSE’s research spans the globe – from the potential of smallholder irrigation to reduce hunger and improve development in sub-Saharan Africa to the devastation of drought on Iowa farms. David Lobell, a senior fellow at FSI and a recipient of a MacArthur “genius” grant, has looked at the impacts of increasing wheat and corn crops in Africa, South Asia, Mexico and the United States; and has studied the effects of extreme heat on the world’s staple crops.
Growing evidence demonstrates that climatic conditions can have a profound impact on the functioning of modern human societies, but effects on economic activity appear inconsistent. Fundamental productive elements of modern economies, such as workers and crops, exhibit highly non-linear responses to local temperature even in wealthy countries. In contrast, aggregate macroeconomic productivity of entire wealthy countries is reported not to respond to temperature= while poor countries respond only linearly. Resolving this conflict between micro and macro observations is critical to understanding the role of wealth in coupled human–natural systems and to anticipating the global impact of climate change. Here we unify these seemingly contradictory results by accounting for non-linearity at the macro scale. We show that overall economic productivity is non-linear in temperature for all countries, with productivity peaking at an annual average temperature of 13 °C and declining strongly at higher temperatures. The relationship is globally generalizable, unchanged since 1960, and apparent for agricultural and non-agricultural activity in both rich and poor countries. These results provide the first evidence that economic activity in all regions is coupled to the global climate and establish a new empirical foundation for modelling economic loss in response to climate change, with important implications. If future adaptation mimics past adaptation, unmitigated warming is expected to reshape the global economy by reducing average global incomes roughly 23% by 2100 and widening global income inequality, relative to scenarios without climate change. In contrast to prior estimates, expected global losses are approximately linear in global mean temperature, with median losses many times larger than leading models indicate.
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
FSE director Roz Naylor will give the opening plenary lecture at the 2nd International Conference on Global Food Security on October 12, 2015 at Cornell University. Naylor is William Wrigley Professor in Earth System Science, and senior fellow at the Stanford Woods Institute for the Environment and the Freeman Spogli Institute for International Studies at Stanford.
In addition to Naylor's lecture on "Food security in a commodity-driven world," several FSE researchers will give talks and poster sessions during the five-day conference, including professors Marshall Burke and Eric Lambin, visiting scholar Jennifer Burney, postdoctoral scholar Meha Jain, and doctoral candidate Elsa Ordway.
A research team led by FSE director Rosamond Naylor has won a $400,000 multi-year grant to study how to create sustainable palm oil supply chains that promote economic growth and environmental sustainability in Indonesia and West Africa.
Palm oil has become one of the world’s fastest growing and most valuable agricultural commodities. Global production of palm oil doubled in both volume and area each decade between 1970 and 2010, and is expected to double again by 2025. The windfall profits from this rapid expansion have come at a cost of tropical deforestation, biodiversity loss and rising greenhouse gas emissions, and in many cases the economic benefits have bypassed local smallholder farmers.
"When we talk about sustainability in the palm oil industry, we mean more than saving trees," said Naylor. "The question we are getting at with this project is how can the industry boost rural incomes and alleviate poverty among smallholder farmers, while also reducing deforestation and carbon emissions. We are able to tackle this problem from social, economic and environmental angles because we have a truly cross-disciplinary group of researchers. That's a key strength of this team, and a key strength of Stanford."
Naylor and her team of Stanford faculty, scholars and students will undertake the three-year project with funding from the Stanford Global Development and Poverty Initiative (GDP), launched in Spring 2014. GDP aims to transform Stanford’s capacity to speak to the challenges of poverty and development. This year, GDP awarded more than $2 million to 13 faculty research teams from across the university.
The new project marks the first venture that connects Stanford’s expertise in sustainability with the Graduate School of Business’ experience in value chain innovations. The team will conduct an evaluation of value chain opportunities for sustainable palm oil production, build corporate partnerships to improve smallholder incomes, and engage in policy advising.
GDP is a joint initiative of the Stanford Institute for Innovation in Developing Economies (SEED) and the Freeman Spogli Institute for International Studies (FSI). SEED is housed within the Stanford Graduate School of Business.
Rosamond Naylor is William Wrigley Professor of Earth System Science and Senior Fellow at the Stanford Woods Institute for the Environment and at FSI.
We examine how variation in local economic conditions has shaped the AIDS epidemic in Africa. Using data from over 200,000 individuals across 19 countries, we match biomarker data on individuals' serostatus to information on local rainfall shocks, a large source of income variation for rural households. We estimate infection rates in HIV-endemic rural areas increase by 11% for every recent drought, an effect that is statistically and economically significant. Income shocks explain up to 20% of variation in HIV prevalence across African countries, suggesting existing approaches to HIV prevention could be bolstered by helping households manage income risk better.
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.
FSE director Roz Naylor has been selected to deliver the 6th annual Ned Ames Honorary Lecture at the Cary Institute of Ecosystem Studies in Millbrook, NY on Friday, April 24. Her lecture on "Feeding the World in the 21st Century," is free and open to the public, and a video recording of the event will be available on the Cary Institute's website shortly after the talk.
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"
FSI scholars approach their research on the environment from regulatory, economic and societal angles. The Center on Food Security and the Environment weighs the connection between climate change and agriculture; the impact of biofuel expansion on land and food supply; how to increase crop yields without expanding agricultural lands; and the trends in aquaculture. FSE’s research spans the globe – from the potential of smallholder irrigation to reduce hunger and improve development in sub-Saharan Africa to the devastation of drought on Iowa farms. 
