James Gerber’s research while affiliated with University of Minnesota Duluth and other places

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Publications (48)


Average relative yield gaps for ten major crops in 1975 and 2010
Crops include barley, cassava, maize, oil palm, rapeseed, rice, sorghum, soybean, sugar cane and rice. Relative yield gap (shown as the percentage of the attainable yield achieved) in each grid cell is calculated as an area-weighted average across the crops and is shown on the top 98% of the growing area.
Time to closure of yield gaps based on linear extrapolation of trends from circa 2000 to circa 2010 for maize, rice, wheat and soybean
Yield gap closure time is defined as the crossing point of the linear trend of attainable yield and the linear trend of actual yield relative to 2010. ‘No trend’ indicates that no yield gap closure occurs within 95th percentile confidence intervals. ‘Widen’ indicates that yield ceiling and linear trend are significantly diverging (that is, the crossing point is before 2010). See Supplementary Fig. 3 for other crops.
Typologies of yield gap closure
a, ‘Steady growth’ category, an archetype of which is the situation when attainable yield (‘ceiling’) and actual yield (‘floor’) benefit from agronomic investment in new technologies and increased uptake of management practices. b, ‘Stalled floor’ category; yield gap is increasing because ‘best in class’ management practices for maximizing yield are not widely adopted for reasons that could include economic barriers, selection of lower-yielding higher-quality cultivars or adoption of environmental policies. c, ‘Ceiling pressure’ category, in which small yield gaps indicate a need for breeding and ‘new agronomy’²⁴ to improve yield ceilings. Some archetypal examples are shown in Supplementary Fig. 5.
Maps of typologies of yield gap change for maize, rice, wheat and soybean
Typologies are as defined in the text and illustrated in Fig. 3. Maps for other crops are shown in Supplementary Fig. 4.
Global spatially explicit yield gap time trends reveal regions at risk of future crop yield stagnation
  • Article
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January 2024

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417 Reads

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25 Citations

Nature Food

James S. Gerber

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Lindsey Sloat

Yield gaps, here defined as the difference between actual and attainable yields, provide a framework for assessing opportunities to increase agricultural productivity. Previous global assessments, centred on a single year, were unable to identify temporal variation. Here we provide a spatially and temporally comprehensive analysis of yield gaps for ten major crops from 1975 to 2010. Yield gaps have widened steadily over most areas for the eight annual crops and remained static for sugar cane and oil palm. We developed a three-category typology to differentiate regions of ‘steady growth’ in actual and attainable yields, ‘stalled floor’ where yield is stagnated and ‘ceiling pressure’ where yield gaps are closing. Over 60% of maize area is experiencing ‘steady growth’, in contrast to ∼12% for rice. Rice and wheat have 84% and 56% of area, respectively, experiencing ‘ceiling pressure’. We show that ‘ceiling pressure’ correlates with subsequent yield stagnation, signalling risks for multiple countries currently realizing gains from yield growth.

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Juan Mayorga 53 ; Hans van Meijl 54 ; Dan Miller 55 ; Zsolt Molnar 56 ; Nathaniel Mueller 57 ; Nibedita Mukherjee 1 ; Robin Naidoo 58 ; Katia Nakamura 59 ; Prakash Nepal 60 ; RF Noss 61 ; Beth O'Leary 62 ; D Olson 63 ; Juliano Palcios Abrantes 64 ; Midori Paxton 65 ; Alexander Popp 40 ; Hugh Possingham 66 ; Jeff Prestemon 67

February 2023

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590 Reads

Working paper analysing the economic implications of the proposed 30% target for areal protection in the draft post-2020 Global Biodiversity Framework


Fig. 7. Uncertainty range in Pareto frontiers after 100 simulations for the United States and Argentina. Arrows demonstrate the degree of trade-offs between cost savings and emission reductions between different solutions on the Pareto frontier.
Fig. 8. Spatial variation of meat production after 100 simulations with the example of Argentina.
Fig. 9. Robustness of feed options illustrated by the frequency of the most common feed option selected after 100 simulations, with the example of Argentina.
MOO-GAPS: A multi-objective optimization model for global animal production and sustainability

February 2023

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212 Reads

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4 Citations

Journal of Cleaner Production

Agricultural and livestock production involves significant trade-offs between multiple sustainable development goals, including reducing hunger and poverty, and reducing emissions of greenhouse gasses. Here we describe a multi-objective optimization tool for livestock production to evaluate trade-offs among environmental and economic objectives with high spatial granularity and the capability to be aggregated to national or global scales. We illustrate the use of this tool analysing how and where to produce beef to optimize the weighted sum of environmental and economic objectives, in this case minimizing greenhouse gas emissions and minimizing costs of production. We present how the outputs of this model can inform a sustainable transition of the industry and policy decisions, with a focus on inherent trade-offs. By comparing optimal production with current production, we highlight the potential environmental and economic efficiencies that can be made by changing the location or methods of production. As such, this tool provides a platform to identify trade-offs and synergies among multiple diverse sustainability goals, critical in the livestock and agricultural sectors.


Efficient global beef production for the National Beef scenario
a, Pareto frontier of global beef production with the same quantity of beef produced in each country (national beef scenario). Five solutions along the frontier show feasible combinations of GHG emissions and production cost: minimize cost, achieves production at the lowest feasible production cost; lower cost, minimizes production cost constrained to not increase GHG emissions; GHG target, meets global GHG emissions reduction target at minimum cost; lower GHG, minimizes GHG emissions constrained to not increase cost; and minimize GHG, achieves production with the lowest feasible GHG emissions. Map insets show the change in spatial distribution of beef production when production costs are minimized versus current production (2018 levels) and when GHG emissions are minimized versus the simulated current production. b, Breakdown of emission sources among enteric fermentation (ent. ferm.), manure, fertilizer, aboveground biomass (AGB) carbon, belowground biomass (BGB) carbon from land clearing and reforestation, and postfarm (composed of transport, export and processing) emissions, for current production and the five solutions described above. c, Sources of economic costs, including establishment, opportunity, feed production, postfarm (transport and export) and reforestation costs. Economic costs are shown for the simulated current production and the five solutions described above.
Land use strategies to achieve efficient beef production
a,b, Most efficient strategies and locations that minimize production costs (a) and minimize emissions for the national beef scenario (b). The pie charts (a,b) indicate the percentage of optimal beef production from different actions: increase production through land expansion or increase in production on current area; maintain current production; and decrease production or removal of current production with or without forest restoration. c, Map showing where and which actions agree and where actions disagree to produce the most efficient feed between the solutions minimizing costs and minimizing GHG for the national beef scenario. The pie chart shows the percentage of beef production in cells where the actions and locations agree or disagree and which actions are the same for the two solutions.
Pareto frontiers of beef without borders (blue) compared to national beef scenario (grey) and simulated current production
Map insets show the net change in the spatial distribution of beef production in beef without borders compared to the simulated current beef distribution.
Uncertainty range of optimization results for national beef scenario
Monte Carlo sampling using uniform distributions was conducted for 11 parameters that were deemed to be most uncertain and most likely to affect the results. The 5th–95th and 25th–75th percentiles of economic costs and emissions are chosen to create a range for each solution along the Pareto frontier, in this case using six solutions. The range of efficiency is compared to the current production (red cross).
Navigating sustainability trade-offs in global beef production

January 2023

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511 Reads

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23 Citations

Nature Sustainability

Beef production represents a complex global sustainability challenge including reducing poverty and hunger and the need for climate action. Understanding the trade-offs between these goals at a global scale and at resolutions to inform land use is critical for a global transition towards sustainable beef. Here we optimize global beef production at fine spatial resolution and identify trade-offs between economic and environmental objectives interpretable to global sustainability ambitions. We reveal that shifting production areas, compositions of current feeds and informed land restoration enable large emissions reductions of 34–85% annually (612–1,506 MtCO2e yr−1) without increasing costs. Even further reductions are possible but come at a trade-off with costs of production. Critically our approach can help to identify such trade-offs among multiple sustainability goals, produces fine-resolution mapping to inform required land-use change and does so at the scale necessary to shift towards a globally sustainable industry for beef and to sectors beyond. Producing beef sustainably at a global level is a challenge given the multiple trade-offs between the economic and environmental objectives involved. This study presents an approach that helps to identify such trade-offs at the scale needed for the beef industry to become more sustainable.


Pollinator Deficits, Food Consumption, and Consequences for Human Health: A Modeling Study

December 2022

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171 Reads

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32 Citations

Environmental Health Perspectives

Background: Animal pollination supports agricultural production for many healthy foods, such as fruits, vegetables, nuts, and legumes, that provide key nutrients and protect against noncommunicable disease. Today, most crops receive suboptimal pollination because of limited abundance and diversity of pollinating insects. Animal pollinators are currently suffering owing to a host of direct and indirect anthropogenic pressures: land-use change, intensive farming techniques, harmful pesticides, nutritional stress, and climate change, among others. Objectives: We aimed to model the impacts on current global human health from insufficient pollination via diet. Methods: We used a climate zonation approach to estimate current yield gaps for animal-pollinated foods and estimated the proportion of the gap attributable to insufficient pollinators based on existing research. We then simulated closing the "pollinator yield gaps" by eliminating the portion of total yield gaps attributable to insufficient pollination. Next, we used an agriculture-economic model to estimate the impacts of closing the pollinator yield gap on food production, interregional trade, and consumption. Finally, we used a comparative risk assessment to estimate the related changes in dietary risks and mortality by country and globally. In addition, we estimated the lost economic value of crop production for three diverse case-study countries: Honduras, Nepal, and Nigeria. Results: Globally, we calculated that 3%-5% of fruit, vegetable, and nut production is lost due to inadequate pollination, leading to an estimated 427,000 (95% uncertainty interval: 86,000, 691,000) excess deaths annually from lost healthy food consumption and associated diseases. Modeled impacts were unevenly distributed: Lost food production was concentrated in lower-income countries, whereas impacts on food consumption and mortality attributable to insufficient pollination were greater in middle- and high-income countries with higher rates of noncommunicable disease. Furthermore, in our three case-study countries, we calculated the economic value of crop production to be 12%-31% lower than if pollinators were abundant (due to crop production losses of 3%-19%), mainly due to lost fruit and vegetable production. Discussion: According to our analysis, insufficient populations of pollinators were responsible for large present-day burdens of disease through lost healthy food consumption. In addition, we calculated that low-income countries lost significant income and crop yields from pollinator deficits. These results underscore the urgent need to promote pollinator-friendly practices for both human health and agricultural livelihoods. https://doi.org/10.1289/EHP10947.


The lost opportunity from insufficient pollinators for global food supplies and human health

October 2022

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118 Reads

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5 Citations

The Lancet Planetary Health

Background Animal pollination supports agricultural production for many healthy foods, such as fruits, vegetables, nuts, and legumes, which provide key nutrients and protect against non-communicable diseases. Today, most crops receive suboptimal pollination because of reduced abundance and diversity of pollinating insects. Methods We modelled the effects on current global human health from insufficient pollination by quantifying the pollinator-related crop yield gap and lost consumption of pollination-dependent foods by country and region, after accounting for global trade, economic behaviours, and food waste. We also estimated the lost economic value of crop production for the following three diverse case-study countries: Honduras, Nepal, and Nigeria. Findings Globally, we found that we are currently losing 3–5% of fruit, vegetable, and nut production per year because of inadequate pollination, leading to a median estimated 427 000 (95% uncertainty interval 86 000–691 000) excess deaths annually from lost healthy food consumption and associated diseases. Effects are unevenly distributed; lost food production is concentrated in low-income countries, while impacts on food consumption and mortality attributable to insufficient pollination are greater in middle-income and high-income countries with higher rates of non-communicable diseases. Furthermore, in our three case-study countries, we found that the economic value of crop production was 12–31% lower than if pollinators were abundant (because of crop production losses of 3–19%), mainly due to lost fruit and vegetable production. Interpretation Insufficient populations of pollinators are responsible for large burdens of disease through lost healthy food consumption. Furthermore, low-income countries are losing substantial income and crop yields from pollinator deficits. These results underscore the urgent need to promote pollinator-friendly practices for both human health and agricultural livelihoods. Funding Gordon & Betty Moore Foundation, Weston Foods, Fifth Generation, CGIAR, United States Agency for International Development, Bill & Melinda Gates Foundation, and Wellcome Trust.


Figure 3a. Changes in foreign emissions by final product (GgCO2e), b. % of foreign emissions by final product, c. Changes in foreign emissions by primary input (GgCO2e), d. % of foreign emissions by primary input. Categories contributing > 1% of global foreign emissions are included, 1986 (light) vs. 2013 (dark).
Agro-food greenhouse gas emissions are increasingly driven by foreign demand

July 2022

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174 Reads

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1 Citation

Greenhouse gas emissions embodied in international trade have risen sharply over the last few decades because of the globalization of economies and countries’ productive specialization. We have built a model able to trace all agro-food emissions along global value chains for 1986–2013. The results show that while the domestic fraction of food emissions has slightly decreased, the foreign fraction has grown by 75%, accounting for 24% of all agro-food emissions today. A few supply chains concentrate most of this increase, with consumption of animal products explaining 70% of all embodied emissions in trade. It was also found that higher incomes resulted in higher percentages of foreign agro-food emissions, and that increasing the proportion of imports in these footprints can be associated with lower per capita emissions. Because trade increasingly redistributes agro-food emissions around the world, national mitigation efforts should be complemented with strong international and coordinated cooperation actions.


Fig S3 Years of expertise in the declared field from experts contributing to the study. Data were collected in the initial online survey.
Research priorities for global food security under extreme events

July 2022

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794 Reads

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58 Citations

One Earth

Extreme events, such as those caused by climate change, economic or geopolitical shocks, and pest or disease epidemics, threaten global food security. The complexity of causation, as well as the myriad ways that an event, or a sequence of events, creates cascading and systemic impacts, poses significant challenges to food systems research and policy alike. To identify priority food security risks and research opportunities, we asked experts from a range of fields and geographies to describe key threats to global food security over the next two decades and to suggest key research questions and gaps on this topic. Here, we present a prioritization of threats to global food security from extreme events, as well as emerging research questions that highlight the conceptual and practical challenges that exist in designing, adopting, and governing resilient food systems. We hope that these findings help in directing research funding and resources toward food system transformations needed to help society tackle major food system risks and food insecurity under extreme events.


A roadmap toward scalably quantifying field-level agricultural carbon outcome

January 2022

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331 Reads

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5 Citations

Agriculture contributes nearly a quarter of global greenhouse gas (GHG) emissions, which is motivating interest in certain farming practices that have the potential to reduce GHG emissions or sequester carbon in soil. The related GHG emission (including N2O and CH4) and changes in soil carbon stock are defined here as “agricultural carbon outcomes”. Accurate quantification of agricultural carbon outcomes is the basis for achieving emission reductions for agriculture, but existing approaches for measuring carbon outcomes (including direct measurements, emission factors, process-based modeling) fall short of achieving the required accuracy and scalability necessary to support credible, verifiable, and cost-effective measurement and improvement of these carbon outcomes. Here we propose a foundational and scalable framework to quantify field-level carbon outcomes for farmland, which is based on the holistic carbon balance of the agroecosystem: Agroecosystem Carbon Outcomes = Crops (C) × Management (M) × Environment (E). Following a comprehensive review of the scientific challenges associated with existing approaches, as well as their tradeoffs between cost and accuracy, we propose that the most viable path for the quantification of field-level carbon outcomes in agricultural land is through an effective integration of various approaches (e.g. diverse observations, sensor/in-situ data, modeling), defined as the “system- of-systems” solution. Such a “system-of-systems” solution should simultaneously comprise the following components: (1) scalable collection of ground truth data and cross-scale sensing of crop conditions (C), management practices (M), and environment (E) at the local field level; (2) advanced modeling with necessary processes to support the quantification of carbon outcomes; (3) systematic Model-Data Fusion (MDF), i.e. robust and efficient methods to integrate sensing data and models at each local farmland level; (4) high computation efficiency and artificial intelligence (AI) to scale to millions of individual fields with low cost; and (5) robust and multi-tier validation systems and infrastructures to ensure solution fidelity and true scalability, i.e. the ability of a solution to perform robustly with accepted accuracy on all targeted fields. In this regard, we provide here the detailed scientific rationale, current progress, and future R&D priorities to achieve different components of the “system-of-systems” solution, thus accomplishing the Crop×Management×Environment framework to quantify field-level agricultural carbon outcomes.


Citations (39)


... However, since the early 21st century, the growth rate of rice yield per hectare has slowed [3]. Compared to other crops, such as maize, where 60% of the cultivated area has not yet reached yield ceilings, 84% of China's rice area has already plateaued [4]. This phenomenon highlights the challenges facing rice production and emphasizes the urgency for in-depth studies on the evolution of rice cultivar performance. ...

Reference:

Evolution of Rice Cultivar Performance Across China: A Multi-Dimensional Study on Yield and Agronomic Characteristics over Three Decades
Global spatially explicit yield gap time trends reveal regions at risk of future crop yield stagnation

Nature Food

... While our data suggest that these episodic N 2 O hot spots occur in more clayey locations within our flat agricultural fields, understanding how soil texture mediates biotic and abiotic processes that regulate soil NO 3 − and DOC concentrations will inform how we can apply the cannon model more broadly. Importantly, to support spatially explicit modeling of soil N 2 O emissions across millions of acres of cropland, we ideally can identify remotely sensed variables predictive of spatial patterns in soil NO 3 − and DOC 65 . Third, the model highlights the role of higher soil NO 3 − and DOC availability in creating is the substrate that is reduced to N 2 O by denitrifying microbes using electrons donated from organic carbon when high soil moisture creates anoxic soil conditions conducive for the anaerobic process of denitrification. ...

A scalable framework for quantifying field-level agricultural carbon outcomes

Earth-Science Reviews

... There are studies and initiatives that assess the potential to reduce greenhouse gas emissions from livestock production on a global scale (Castonguay et al. 2023; Thornton et al. 2023). Improving and optimising the bioeconomic efficiency of grazing systems by improving animal nutrition, genetics, livestock health, and management practices (Cazzuli et al. 2023;Serrano 2023) are major tasks for the scientific community at the current stage of development. ...

MOO-GAPS: A multi-objective optimization model for global animal production and sustainability

Journal of Cleaner Production

... Additionally, a high intake of beef is linked to various health issues, including cardiovascular diseases and cancer, and it contributes to the development of antibiotic resistance in pathogenic microorganisms [6][7][8]. Legume-based products as well as other plant-based products may serve as good replacement for beef and as basis for a sustainable diet [8][9][10]. Alongside the pressing issues of population growth, urbanization, and the reduction of agricultural land, the trend of overconsumption of calories among the population-an issue that inevitably leads to obesity-is becoming increasingly critical [11][12]. ...

Navigating sustainability trade-offs in global beef production

Nature Sustainability

... A recent modelling study showed that farmers in Nepal have substantial opportunities to increase their crop yields and resulting income by enhancing pollination services. Closing pollination related yield gaps (pollination deficits) in Nepal was predicted to increase the economic income of individual farmers by 31% 37 . ...

Pollinator Deficits, Food Consumption, and Consequences for Human Health: A Modeling Study
  • Citing Article
  • December 2022

Environmental Health Perspectives

... Pollinator biodiversity provide crucial ecosystem services by contributing to the processes of pollination and hence directly and indirectly assuring many other processes involving plants ( Bartholomée and Lavorel, 2019), including many Sustainable Development Goals (Patel et al., 2020) and even human health (Smith et al., 2022(Smith et al., , 2015. Pollinators are therefore pivotal characters of ecosystem functioning, and pollinator biodiversity is a crucial aspect especially in agricultural lands, where they are key to ecosystem functioning both for direct and indirect reasons. ...

The lost opportunity from insufficient pollinators for global food supplies and human health
  • Citing Article
  • October 2022

The Lancet Planetary Health

... On the one hand, international trade allows countries to buffer against local production shortfalls by importing food from other regions, thus enhancing food security (Gomez et al., 2021;Halpern et al., 2022;Hicks et al., 2022;Suweis et al., 2013). On the other hand, the interconnected nature of these networks can also facilitate the rapid spread of disruptions, such as those caused by climate change, economic crises, or geopolitical conflicts (Chung & Liu, 2022;Kreibich et al., 2022;Marchand et al., 2016;Mehrabi et al., 2022;Tamea et al., 2014). ...

Research priorities for global food security under extreme events

One Earth

... To assess the outcome of current policies and understand the factors influencing the adoption of conservation tillage, accurate spatially and temporally resolved information on cropland tillage practices is urgently needed. Furthermore, tillage intensity information is also essential for agroecosystem modeling to facilitate the accurate quantification of agroecosystem biogeochemical processes as well as cropland carbon outcomes (Maharjan et al., 2018;Guan et al., 2022). However, such information at the regional scale is still rare and only a few studies have identified regional tillage classes (e.g., two classes including high-and low-intensity tillage, Azzari et al., 2019). ...

A roadmap toward scalably quantifying field-level agricultural carbon outcome
  • Citing Preprint
  • January 2022

... Since the introduction of the Haber-Bosch process, the use of inorganic N fertilizers in commercial agriculture has significantly increased [6]. But N fertilizer use efficiency (NUE) remains below 54% [7][8][9][10], indicating that the remaining half of applied N is not utilized by plants. ...

Quantification of global and national nitrogen budgets for crop production

Nature Food

... Addressing the challenges posed by climate change (CC) to agriculture is crucial, particularly to understand the impacts on irrigation demands [1][2][3][4]. Accurate evapotranspiration (ET) estimates are becoming increasingly important when dealing with water scarcity, particularly where water resources are decreasing and demand is increasing [5,6]. Efforts to adapt to the potential effects of CC on agricultural productivity require improved information, particularly on crop evapotranspiration (ET c ). Depending on data availability and study objectives, there are different approaches to measure or estimate ET at different scales [7][8][9][10][11][12][13]. The predominant method for estimating ET c is the K c -ET o approach, which combines the reference evapotranspiration (ET o ) with a crop coefficient (K c ). ...

Global irrigation contribution to wheat and maize yield