The Center on Food Security and the Environment is a joint effort of the Freeman Spogli Institute for International Studies and the Stanford Woods Institute for the Environment.
(Adapted from press release by Jim Erickson, University of Michigan)
Farmers in India have adapted to warming temperatures by intensifying the withdrawal of groundwater used for irrigation, according to a new study coauthored by Stanford environmental scientist David Lobell. If the trend continues, the rate of groundwater loss could triple by 2080, further threatening India’s food and water security, according to the paper, published Sept. 1 in Science Advances.
“By looking at how farmers have responded to warm years in the recent past, we can see a dramatic increase in irrigation in hotter years,” said Lobell, the Gloria and Richard Kushel Director of Stanford’s Center on Food Security and the Environment and professor of Earth system science in the Stanford Doerr School of Sustainability. “We expected they would water more when it’s hot, but the magnitude surprised us.”
Reduced water availability in India due to groundwater depletion and climate change could threaten the livelihoods of more than one-third of the country’s 1.4 billion residents and has global implications. India recently overtook China to become the world’s most populous nation and is the second-largest global producer of common cereal grains including rice and wheat.
The study analyzed historical data on groundwater levels, climate, and crop water stress to look for recent changes in withdrawal rates due to warming. The researchers also used temperature and precipitation projections from 10 climate models to estimate future rates of groundwater loss across India.
“Using our model estimates, we project that under a business-as-usual scenario, warming temperatures may triple groundwater depletion rates in the future and expand groundwater depletion hotspots to include south and central India,” said study lead author Nishan Bhattarai of the Department of Geography and Environmental Sustainability at the University of Oklahoma.
Previous studies have focused on the individual effects of climate change and groundwater depletion on crop production in India. Those studies did not account for farmer decision-making, including how farmers may adapt to changing climate through changes in irrigation decisions.
The study takes into account the fact that warmer temperatures may increase water demand from stressed crops, which in turn may lead to increased irrigation by farmers.
Previous studies found that climate change could decrease the yield of staple Indian crops by up to 20% by mid-century. At the same time, the country’s groundwater is being depleted at an alarming rate, primarily because of water withdrawal for irrigation.
For the newly published study, the researchers developed a dataset that contains groundwater depths from thousands of wells across India, high-resolution satellite observations that measured crop water stress, and temperature and precipitation records.
Most climate models call for increased temperature, increased monsoon (June through September) precipitation and decreased winter precipitation in India over the coming decades. The research team found that warming temperatures coupled with declining winter precipitation more than offset added groundwater recharge from increased monsoon precipitation, resulting in accelerated groundwater declines.
Across various climate-change scenarios, their estimates of groundwater-level declines between 2041 and 2080 were more than three times current depletion rates, on average.
Lobell is also the William Wrigley Senior Fellow at the Stanford Woods Institute for the Environment, and a senior fellow at the Freeman Spogli Institute for International Studies and the Stanford Institute for Economic Policy Research.
The study’s senior author is Meha Jain of the University of Michigan’s School for Environment and Sustainability. Other coauthors include Balwinder Singh of the International Maize and Wheat Improvement Center in India and the Department of Primary Industries and Regional Development in Western Australia, Ram Fishman of Tel Aviv University, William Kustas of the U.S. Department of Agriculture, and Yadu Pokhrel of Michigan State University.
The research was funded by a NASA Land-Cover Land-Use Change Grant and a NASA new investigator program award to Jain. The research was supported in part by the U.S. Department of Agriculture’s Agricultural Research Service.
Farmers in India have adapted to warming temperatures by intensifying the withdrawal of groundwater used for irrigation, according to a new study. If the trend continues, the rate of groundwater loss could triple by 2080, further threatening India’s food and water security.
High resolution satellite imagery and modern machine learning methods hold the potential to fill existing data gaps in where crops are grown around the world at a sub-field level. However, high resolution crop type maps have remained challenging to create in developing regions due to a lack of ground truth labels for model development. In this work, we explore the use of crowdsourced data, Sentinel-2 and DigitalGlobe imagery, and convolutional neural networks (CNNs) for crop type mapping in India. Plantix, a free app that uses image recognition to help farmers diagnose crop diseases, logged 9 million geolocated photos from 2017–2019 in India, 2 million of which are in the states of Andhra Pradesh and Telangana in India. Crop type labels based on farmer-submitted images were added by domain experts and deep CNNs. The resulting dataset of crop type at coordinates is high in volume, but also high in noise due to location inaccuracies, submissions from out-of-field, and labeling errors. We employed a number of steps to clean the dataset, which included training a CNN on very high resolution DigitalGlobe imagery to filter for points that are within a crop field. With this cleaned dataset, we extracted Sentinel time series at each point and trained another CNN to predict the crop type at each pixel. When evaluated on the highest quality subset of crowdsourced data, the CNN distinguishes rice, cotton, and “other” crops with 74% accuracy in a 3-way classification and outperforms a random forest trained on harmonic regression features. Furthermore, model performance remains stable when low quality points are introduced into the training set. Our results illustrate the potential of non-traditional, high-volume/high-noise datasets for crop type mapping, some improvements that neural networks can achieve over random forests, and the robustness of such methods against moderate levels of training set noise. Lastly, we caution that obstacles like the lack of good Sentinel-2 cloud mask, imperfect mobile device location accuracy, and preservation of privacy while improving data access will need to be addressed before crowdsourcing can widely and reliably be used to map crops in smallholder systems.
Sugar is the second largest agro-based industry in India and has a major influence on the country's water, food, and energy security. In this paper, we use a nexus approach to assess India's interconnected water-food-energy challenges, with a specific focus on the political economy of the sugar industry in Maharashtra, one of the country's largest sugar producing states. Our work underscores three points. First, the governmental support of the sugar industry is likely to persist because policymakers are intricately tied to that industry. Entrenched political interests have continued policies that incentivize sugar production. As surplus sugar has been produced, the government introduced additional policies to reduce this excess and thereby protect the sugar industry. Second, although the sugar economy is important to India, sugar policies have had detrimental effects on both water and nutrition. Long-standing government support for sugarcane pricing and sales has expanded water-intensive sugarcane irrigation in low-rainfall areas in Maharashtra, which has reduced the state's freshwater resources and restricted irrigation of more nutritious crops. Despite its poor nutritional value, empty-calorie sugar has been subsidized through the public distribution system. Third, the Indian government is now promoting sugarcane-based ethanol production. This policy has the benefit of providing greater energy security and creating a new demand for surplus sugar in the Indian market. Our analysis shows that a national biofuel policy promoting the production of ethanol from sugarcane juice versus directly from molasses may help reduce subsidized sugar for human consumption without necessarily expanding water and land use for additional production of sugarcane.
Generations of political support for sugar cultivation have helped India become the second-largest producer of sugar worldwide. Now, the country’s commitment to renewable energy could create additional benefits, like conserving natural resources and providing better nutrition to the poor.
Stanford researchers conducted the first comprehensive analysis of India’s sugar industry and its impact on water, food and energy resources through the lens of its political economy – that is, how entrenched political interests in sugar production threaten food, water and energy security over time. The results show that a national biofuel policy encouraging production of ethanol made directly from sugarcane juice may make India’s water and energy resources more sustainable. Using sugarcane juice instead of molasses would also free up land and irrigation water for growing nutrient-rich foods. The research was published July 24 in Environmental Research Letters.
“There are spillover effects between sectors, unintended consequences,” said co-author Rosamond Naylor, a food security expert and the William Wrigley Professor in Stanford’s School of Earth, Energy & Environmental Sciences (Stanford Earth). “It’s very instructive to think about the connection between food, water and energy because the solution may not be in the sector you’re focusing on.”
Somewhat analogous to the corn industry in the U.S., which has shifted about 40 percent of its output to ethanol production in recent years, policymakers in India – many of whom benefit financially from the sugar industry – are currently exploring how to use sugarcane to increase energy independence and shift toward renewable energy use.
The Indian government has set a goal to increase the ethanol-to-gasoline blending rate from its current rate of about 6 percent to 20 percent by 2030 and introduced several policies to promote production of ethanol from sugarcane. The increased blending rate is a “desirable goal for improved energy security,” the researchers write. However, its effects on human health and the environment will largely depend on which sugar product ends up being the main feedstock: juice extracted from crushed sugarcane, or molasses, a by-product from sugar processing.
Meeting E20 by 2030: additional sugarcane, water and land resources needed, and extra sugar produced. Meeting the 20% ethanol-to-gasoline blending rate by 2030 with ethanol produced from molasses would require additional water and land resources and produce extra sugar. In contrast, ethanol produced from sugarcane juice could meet the blending target without risking water and land resources and would reduce extra sugar. (Image credit: Lee et al. / Environmental Research Letters)
India’s national policy on biofuels only recently began allowing use of sugarcane juice in ethanol production, in addition to molasses.
“If the energy industry continues to use molasses as the bioethanol feedstock to meet its target, it would require additional water and land resources and result in the production of extra sugar,” said co-author Anjuli Jain Figueroa, a postdoctoral researcher in Earth system science. “In contrast, if the industry used the sugarcane juice to produce ethanol, the target could be met without requiring additional water and land beyond current levels.”
Using sugarcane juice to create ethanol could also help alleviate government spending to subsidize sugar and sell it below cost in its public distribution system.
The public distribution system of sugar in India dates to the 1950s, when frequent famines plagued the country. Back then, sugar helped to meet basic calorie requirements. But today – with micronutrient deficiency leading to illness, disabilities and even death – the Indian government is more concerned with nutrition.
“In India right now, even poor populations have met their basic calorie needs,” said Naylor, who is also a senior fellow at the Stanford Woods Institute for the Environment. “They have been able to buy sugar at subsidized prices, but meanwhile they don’t have access to adequate protein and micronutrients for cognitive growth and for physical well-being.”
Micronutrient content and calories of sugar and selected crops. Sugar provides empty calories with no nutritional value. (Image credit: Lee et al. / Environmental Research Letters)
Sugarcane cultivation in India has expanded in part because of policies that incentivize production, including a minimum price, guaranteed sales of sugarcane and public distribution of sugar. These regulations have become entrenched over many generations, making the crop highly profitable to the 6 million farmers in the country, but the empty-calorie crop reduces the amount of resources available for micronutrient-rich foods.
“Using scarce natural resources to produce a crop that doesn’t fulfill nutritional needs for the second most populated country in the world can place pressure on the global food system if more and more food imports are required to meet the rising demand in India,” Naylor said.
The researchers focused their analysis on Maharashtra in western India, one of the country’s largest sugarcane-producing states. Sugarcane cultivation in Maharashtra has increased sevenfold in the past 50 years to become the dominant user of irrigation water. The study found that in 2010-11, sugarcane occupied only 4 percent of Maharashtra’s total cropped areas but used 61 percent of the state’s irrigation water. Meanwhile, irrigation for other nutritious food crops remained lower than the national averages.
Irrigation water use by major crops or crop groups in Maharashtra from 1970–71 to 2010–11. In Maharashtra, irrigation water use by sugarcane has increased more rapidly than any other crop over time, and sugarcane has used the highest share of total irrigation water in all time periods. (Image credit: Lee et al. / Environmental Research Letters)
“Irrigation of sugarcane in our study region is about four times that of all other crops and has doubled from 2000 to 2010. This resulted in about a 50 percent reduction of river flow over that period,” said co-author Steven Gorelick, the Cyrus Fisher Tolman Professor at Stanford Earth. “Given that this region is susceptible to significant drought, future water management is likely to be quite challenging.”
As part of continued efforts to examine the Indian sugar industry and its impacts, lead author Ju Young Lee, a PhD student in Earth system science, also developed satellite imagery analyses to identify sugarcane from space.
“Despite the importance of sugarcane in the water, food and energy sectors in India, there are no reliable sugarcane maps for recent years and in time series,” Lee said. “Using remote sensing data, I am developing current time-series sugarcane maps in Maharashtra – an important step forward.”
The researchers worked with stakeholders in India, including NGOs, academics and government officials, to focus the goals of the project. The research is part of Food Water Energy for Urban Sustainable Environments (FUSE), an international consortium supported in part by the National Science Foundation through the Belmont Forum to address competition for scarce resources in stressed urban food-water-energy systems – including the impacts of climate variability.
Naylor is also a senior fellow at the Freeman Spogli Institute for International Studies and a professor, by courtesy, of economics. Gorelick is also lead principal investigator of FUSE and a senior fellow at the Stanford Woods Institute for the Environment.
The research was supported by the U.S. National Science Foundation.
Lead study author Ju Young Lee, center, is pictured with local farmers and agricultural experts while visiting a sugarcane field in Maharashtra in western India in August 2018. (Image courtesy of Ju Young Lee)
Researchers analyzed the interconnected food, water and energy challenges that arise from the sugar industry in India – the second-largest producer of sugar worldwide – and how the political economy drives those challenges.
Join Stanford's Center on Food Security and the Environment for a lecture and reception with Dr. Junaid Ahmad, the World Bank Country Director for India.
Dr. Ahmad will look at the political economy of managing service delivery in India through the prism of water. The presentation will look at the water supply and sanitation sector and water resource management in the context of India’s federalism and urban and food policies. Ahmad argues that India’s transition to middle income will depend significantly on how water will be valued in India’s political economy.
Junaid Ahmad, from Bangladesh, is currently the World Bank Country Director for India. Over the years, Mr. Ahmad has brought an exceptional track record of management and leadership in the areas of policy reform, service delivery and international partnerships, combining intellectual and analytical rigor with strategic operational focus. Mr. Ahmad’s work has covered urban finance and city management, infrastructure finance, water, service delivery in federal systems, and local government reform. Currently, he is responsible for managing the World Bank’s India portfolio.
Irrigation has been pivotal in wheat’s rise as a major crop in India and is likely to be increasingly important as an adaptation response to climate change. Here we use historical data across 40 years to quantify the contribution of irrigation to wheat yield increases and the extent to which irrigation reduces sensitivity to heat. We estimate that national yields in the 2000s are 13% higher than they would have been without irrigation trends since 1970. Moreover, irrigated wheat exhibits roughly one-quarter of the heat sensitivity estimated for fully rainfed conditions. However, yield gains from irrigation expansion have slowed in recent years and negative impacts of warming have continued to accrue despite lower heat sensitivity from the widespread expansion of irrigation. We conclude that as constraints on expanding irrigation become more binding, furthering yield gains in the face of additional warming is likely to present an increasingly difficult challenge.
Feeding a growing population while reducing negative environmental impacts is one of the greatest challenges of the coming decades. We show that microsatellite data can be used to detect the impact of sustainable intensification interventions at large scales and to target the fields that would benefit the most, thereby doubling yield gains. Our work reveals that satellite data provide a scalable approach to sustainably increase food production.
Millions of people worldwide are absent from their country’s census. Accurate, current, and granular population metrics are critical to improving government allocation of resources, to measuring disease control, to responding to natural disasters, and to studying any aspect of human life in these communities. Satellite imagery can provide sufficient information to build a population map without the cost and time of a government census. We present two Convolutional Neural Network (CNN) architectures which efficiently and effectively combine satellite imagery inputs from multiple sources to accurately predict the population density of a region. In this paper, we use satellite imagery from rural villages in India and population labels from the 2011 SECC census. Our best model achieves better performance than previous papers as well as LandScan, a community standard for global population distribution.
Food security will be increasingly challenged by climate change, natural resource degradation, and population growth. Wheat yields, in particular, have already stagnated in many regions and will be further affected by warming temperatures. Despite these challenges, wheat yields can be increased by improving management practices in regions with existing yield gaps. To identify the magnitude and causes of current yield gaps in India, one of the largest wheat producers globally, we produced 30 meter resolution yield maps from 2001 to 2015 across the Indo-Gangetic Plains (IGP), the nation's main wheat belt. Yield maps were derived using a new method that translates satellite vegetation indices to yield estimates using crop model simulations, bypassing the need for ground calibration data. This is one of the first attempts to apply this method to a smallholder agriculture system, where ground calibration data are rarely available. We find that yields can be increased by 11% on average and up to 32% in the eastern IGP by improving management to current best practices within a given district. Additionally, if current best practices from the highest-yielding state of Punjab are implemented in the eastern IGP, yields could increase by almost 110%. Considering the factors that most influence yields, later sow dates and warmer temperatures are most associated with low yields across the IGP. This suggests that strategies to reduce the negative effects of heat stress, like earlier sowing and planting heat-tolerant wheat varieties, are critical to increasing wheat yields in this globally-important agricultural region.