A social–ecological analysis of the globalagrifood systemElisa Oteros-Rozasa,b,1,2, Adriana Ruiz-Almeidac,1, Mateo Aguadod, José A. Gonzálezd, and Marta G. Rivera-Ferrea,e

aAgroecology and Food Systems, Research Group Inclusive Societies, Policies and Communities, University of Vic–Central University of Catalonia, 08500 Vic,Spain; bFRACTAL Collective, 28022 Madrid, Spain; cSustainability Measurement and Modeling Lab, Research Institute for Sustainability Science andTechnology, Polytechnic University of Catalonia, 08034 Barcelona, Spain; dSocial–Ecological Systems Laboratory, Department of Ecology, UniversidadAutónoma de Madrid, 28049 Cantoblanco, Spain; and eCenter Agroecology, Water and Resilience, University of Coventry, CV8 3LG Coventry,United Kingdom

Edited by B. L. Turner II, Arizona State University, Tempe, AZ, and approved November 7, 2019 (received for review July 23, 2019)

Eradicating world hunger—the aim of Sustainable DevelopmentGoal 2 (SDG2)—requires a social–ecological approach to agrifoodsystems. However, previous work has mostly focused on one orthe other. Here, we apply such a holistic approach to depicting theglobal food panorama through a quantitative multivariate assess-ment of 43 indicators of food sovereignty and 28 indicators of socio-demographics, social being, and environmental sustainability in 150countries. The results identify 5 world regions and indicate the ex-istence of an agrifood debt (i.e., disequilibria between regions in thenatural resources consumed, the environmental impacts produced,and the social wellbeing attained by populations that play differ-ent roles within the globalized agrifood system). Three spotlightsunderpin this debt: 1) a severe contrast in diets and food securitybetween regions, 2) a concern about the role that internationalagrifood trade is playing in regional food security, and 3) a mis-match between regional biocapacity and food security. Our resultscontribute to broadening the debate beyond food security froma social–ecological perspective, incorporating environmental andsocial dimensions.

agrifood system | food sovereignty | hunger | social wellbeing |sustainability development goals

Agrifood systems, given their place among the most vulner-able coupled nature–human systems (1, 2), have multiple

interactions with global environmental change and play a majorrole in the present and future of humanity (3, 4). They contem-porarily sustain and challenge social wellbeing and human life onthe planet (4) by providing food while contributing to globalgreenhouse gas emissions, land degradation, eutrophication, andwater quality depletion (5–7). Five of the 7 planetary boundariesare directly linked to agrifood systems (8, 9). However, in a contextin which enough calories are produced to feed the entire humanpopulation (10), chronic hunger still affects 1 in 9 people in theworld (11). The evident failure of policies to end hunger and theenvironmental deterioration underpinning agrifood systems haveprompted a paradigm shift in the way that food security isapproached both scientifically and in policy terms: from beingmostly focused on the technical and agrarian aspects of foodproduction (1, 5, 12, 13) to adopting a social–ecological systemsapproach (14) and more precisely, an agrifood system approach,including both environmental sustainability and social wellbeing(4, 6, 14–18). This systemic perspective allows emphasis on the useof natural resources for primary production as well as foodtransformation, commercialization, and consumption, thereforeconnecting pieces within agrifood systems that previous analyseshad studied separately.Likewise, the multiple social and ecological dimensions of food

security are transversal to 14 of the 17 United Nations’ 2030Sustainable Development Goals (SDGs) (19). The SDGs aim toeradicate poverty, establish socioeconomic inclusion, and protectthe environment (20), and therefore, the need for an integrativeapproach to address them has already been discussed (21). How-ever, critical studies have elicited an incompatibility between the

environmental and the social and economic aspirations of theSDGs (22).While food security is commonly defined as the physical, so-

cial, and economic ability to access sufficient, safe, and nutritiousfood (23), SDG2 implicitly recognizes that a broader approach tofood security is needed to end hunger. Indeed, for the first time,SDG2 links the objectives of zero hunger, food security, and im-proved nutrition (subgoal 1) with the need to promote sustainableagriculture (subgoal 2) (19). SDG2 explicitly refers to the globalmoral imperative to eradicate hunger while respecting environ-mental sustainability. However, this entails controversy about thetradeoffs between achieving food security mainly through in-creasing food production (24, 25), addressing and minimizing theenvironmental impacts of agriculture and food (6), and adapting toclimate change (26). Therefore, actions toward the transformationof agrifood systems need to account for the synergies and tradeoffsthat exist between SDG2 and other SDGs (27), which need to beidentified through social–ecological systems approaches.The international debate around the social–ecological sustain-

ability of food systems is prolific, and different authors have re-cently suggested a change from the land sparing/sharing debate toa focus on human wellbeing (4); proposed “leverage points” forimproving global food security and environmental sustainability(6); argued for sustainable healthy diets to keep food systemswithin the planetary boundaries (28); developed assessments of the

Significance

The failure to end hunger and the environmental deteriorationunderpinning food systems have prompted a paradigm shiftaround food security. We propose a social–ecological approachand carry out a quantitative analysis of 43 indicators of foodsovereignty and 28 indicators of the sociodemographic, socialwellbeing, and environmental sustainability situation in 150countries. The results highlight the existence of an agrifooddebt among countries (i.e., disequilibria in the natural re-sources consumed, the environmental impacts, and the socialwellbeing in regions that play different roles within the glob-alized agrifood system). Three spotlights underpin this debt: 1)interregional contrasts in food security, 2) a concern about therole of agrifood trade, and 3) a mismatch between regionalbiocapacity and food security.

Author contributions: E.O.-R., J.A.G., and M.G.R.-F. designed research; E.O.-R., A.R.-A.,M.A., J.A.G., and M.G.R.-F. performed research; E.O.-R. analyzed data; and E.O.-R.,A.R.-A., M.A., J.A.G., and M.G.R.-F. wrote the paper.

The authors declare no competing interest.

This article is a PNAS Direct Submission.

Published under the PNAS license.1E.O.-R. and A.R.-A. contributed equally to this work.2To whom correspondence may be addressed. Email: elisa.oterosrozas@gmail.com.

This article contains supporting information online at https://www.pnas.org/lookup/suppl/doi:10.1073/pnas.1912710116/-/DCSupplemental.

First published December 16, 2019.

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environmental impacts of food systems (29, 30); applied metricsfor the assessment of the sustainable nutrition outcomes of foodsystems (31); and provided valuable systemic analyses of globalfood systems (18). However, although it is widely acknowledgedthat the social and environmental costs and benefits associatedwith environmental change are not distributed equally among ac-tors and regions (32), how this phenomenon occurs is still poorlyunderstood, because less than 6% of food security publications inthe past 25 y included equity or justice as part of their analysis (14).A tipping point in these international debates was the 2012

32nd Regional Conference for Latin America and the Caribbean(33), where the United Nations Organization for Food and Ag-riculture (FAO) agreed to initiate discussions about alternativeapproaches to address hunger and the unsustainability of agri-food systems. One such approach was food sovereignty (FSv)(33). FSv emerged in the late 1990s, arguing that hunger is notmerely a matter of food availability and quality but that equallyor more critical issues are political aspects harnessing equity andjustice within food systems. Some of those political aspects mayinclude agricultural trade liberalization, power relations betweendifferent actors (from small producers to large transnationalcorporations and consumers, therefore within and betweencountries), a lack of wide social participation along the whole foodchain, or access to the means of production (34, 35). FSv, as apolitical concept, was coined by La Via Campesina, an in-ternational movement of farmers, peasants, and landless workers,and has been developed and discussed at large by civil societyorganizations, farmers’ trade unions, academia, governments, andinternational institutions (36) to become a well-rooted concept(37). Within this approach, food is framed as a human right, in-cluding its environmental and sociocultural aspects, which areviewed as both drivers and outcomes of food security and wheresmall farmers are considered to play a central role (34).However, progress toward ending hunger needs to be mea-

surable through indicators that aid societies in assessing theirperformance (20). Gustafson et al. (31) and Ruiz-Almeida andRivera-Ferre (38) expressed the need to address food securityfrom a systems perspective that incorporates social–ecologicalsustainability, and to do so, they provided comprehensive sets ofindicators at the national scale. Ruiz-Almeida and Rivera-Ferre(38) proposed a panel of 97 indicators, but they did not performany analyses on data. Gustafson et al. (31) suggested 23 indica-tors but applied them only to 9 countries. Chaudhary et al. (18),based on Gustafson et al. (31) and adding 2 additional indicatorson biodiversity impacts and health-sensitive nutrient intake, ap-plied descriptive analyses to quantify 156 nations performance.However, achieving SDG2 requires not only measuring per-

formance but also, understanding the social–ecological relationsamong different countries beyond national patterns. Therefore,based on data for the set of indicators proposed by Ruiz-Almeidaand Rivera-Ferre (38), we analyze here the global agrifood sys-tem from a social–ecological perspective.While previous works advanced in the same direction, we be-

lieve that our contribution constitutes a step farther in 2 ways.First, with the multivariate analysis of 43 indicators of FSv, 150countries are grouped according to their relative scores. Hence, apicture of the dynamics of the global agrifood system at a largerscale is provided. Second, we enlarge the social–ecological ap-proach by incorporating the description of world regions accordingto 7 demographic and economic indicators, 4 social wellbeing in-dicators, and 17 environmental sustainability indicators.In particular, we carried out a principal component analysis

(PCA) of indicators (variables) describing the agrifood system(SI Appendix, Tables S3–S7) in countries (observations). Someindicators were originally published as indexes or proportions,while others needed to be transformed in relative terms withrespect to country area or population size in order to adjustmagnitudes and allow comparison between countries (details of

the definitions, sources, and data transformations are given in SIAppendix, Tables S1 and S2). Using the standardized coordinatesof the most significant PCA factors, we performed a hierarchicalcluster analysis (HCA) based on the Euclidean distance andWard’s agglomerative method. Finally, we used Kruskal–Wallisand χ2 tests to characterize each cluster of countries according toits performance in terms of FSv, social wellbeing, and environ-mental sustainability (a more detailed description of statisticalmethods and results can be found in SI Appendix). This approachaims to contribute to other ongoing efforts to provide indicatorsfor monitoring SDG progress (http://indicators.report).Through the proposed analyses, we 1) identify world regions

formed by countries under similar conditions of FSv, 2) relate thestate of FSv of the different regions with their state of socialwellbeing and environmental sustainability, and 3) critically reflecton the implications for SDG2 of an agrifood debt between worldregions that has been so far poorly addressed. Within-countriesagrifood debt and inequalities can be also relevant to provide acomplete picture, but their analysis is out of the scope of this paper.

ResultsThe State of Food Sovereignty: Who Is Who in the Global AgrifoodSystem. The 150 countries analyzed were statistically clustered into5 groups (Fig. 1 and SI Appendix, Table S8) according to theirperformance in the 43 indicators across the 6 pillars of FSv (Figs. 1and 2). By also characterizing them according to their bioregionalcontext (SI Appendix, Table S9), socioeconomic characteristics (SIAppendix, Table S10), FSv (SI Appendix, Table S11), environ-mental sustainability, and social wellbeing (SI Appendix, TableS12), we grasp who is in the global food system and what relationwith the ecological and sociopolitical dimensions of food the dif-ferent groups of countries have.

Landgrabbed and Undernourished: Agricultural Exporters but FoodImporters. The first group includes 45 countries (SI Appendix,Fig. S4 and Table S8) mostly from eastern, middle, and westernAfrica (Fig. 1 and SI Appendix, Table S9). The countries in thisgroup show the lowest gross domestic product (GDP) percapita and very low income (SI Appendix, Table S10). The foodsystems in the countries of this group are characterized by aproductive model based on the largest rural and agriculturalpopulation of the sample, the smallest cultivated area per farmer,the largest total economically active population in agriculture, alimited use of fertilizers, and a low production of meat (Fig. 2 andSI Appendix, Table S11). Agriculture is responsible for a high shareof the GDP of these countries, which are, on the one hand, thelargest exporters of agricultural products (significantly differentfrom all other groups) and on the other hand, the largest importersof food (although only significantly different from groups 4 and 5),showing net reception of official development assistance for foodand agriculture (SI Appendix, Table S11). This group of countriesranks first in suffered landgrabbing (SI Appendix, Table S10). Thepopulation in the countries of this group shows the lowest levels ofaccess to resources, such as electricity, sanitation, and drinkingwater; the most severe food deficits; and significant vulnerability,which is consistent with the lowest protein supply and adequacy ofthe dietary energy supply among the groups (Fig. 2 and SI Ap-pendix, Table S11). That is, the value added of the agriculturalproducts produced is not retained, exporting huge amounts ofagricultural products while failing to feed large shares of theirpopulation. These countries also show the lowest degree of eco-nomic, social, and political globalization, despite some of thembeing among the biggest exporters of luxury commodities, likecoffee and cocoa. The indicators of social wellbeing are coherentwith the former, as this group of countries has the worst scores forall of the indicators analyzed, including significantly shortest lifeexpectancy and worse life satisfaction (Fig. 3 and SI Appendix,Table S12). In terms of environmental sustainability, these

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countries are associated with the lowest ecological footprint andlow CO2 emissions and water withdrawal from agriculture (Fig. 3and SI Appendix, Table S12).

Diverse Intensive Producers of Crops. The second class is the largestand most heterogeneous group, clustering together 49 countries,mostly from Asia and the Americas (Fig. 1 and SI Appendix,Tables S8 and S9). In comparison with the other groups, thesecountries have the largest population densities and low–mediumincome (SI Appendix, Table S10). These countries show mediumlevels of rural and agricultural populations, however, with thesmallest agricultural area and production of mammals (Fig. 2 andSI Appendix, Table S11). What they have in common is that theyare characterized by intensive production models based on a largeuse of fertilizers and agricultural water withdrawal (also usedfor wheat, maize, and/or rice production, for which some of thecountries in this group, such as China and India, are among thelargest producers in the world) and the vastest surfaces of perma-nent crops (as percentage of agricultural area) that are dedicatedpartly to fruit production (mostly in Southeast Asia and Central andSouth America). They are large food exporters (Figs. 2 and 3 and SIAppendix, Table S11), and also, they are characterized by the secondhighest food deficit, low energy and protein intake (Fig. 2 and SIAppendix, Table S11), and overall intermediate levels of socialwellbeing (Fig. 3 and SI Appendix, Table S12).

Least Ecologically Wealthy and Landgrabbers. The 18 countriesclustered in this class are not geographically or ecoregionallygrouped (Fig. 1 and SI Appendix, Tables S8 and S9). They showmedium population densities and GDP per capita (SI Appendix,Table S10). Countries in this group show a limited proportionof agricultural area and forests as well as overall very little ce-real, meat, and fruit production but the greatest use of fertilizersper hectare (Fig. 2 and SI Appendix, Table S11). Little of thepopulation lives in rural areas or is dedicated to agriculture, and

overall, the population in these countries seems to have goodaccess to all resources except renewable water (the group includesseveral island states) (Fig. 2 and SI Appendix, Table S11). Thesecountries have limited exports of agricultural products, and theyare net food importers, with limited value added to agriculture (Fig.2 and SI Appendix, Table S11). Most of these countries coincide withthose in which the importance of food imports has increased inrecent years. They show an intermediate level of food securityand consumption in comparison with the other groups, despitelimited subsidies invested in supporting agriculture (SI Appendix,Table S11). Overall, they seem to have a good situation in termsof social wellbeing (Fig. 3 and SI Appendix, Table S12). Twosignificant characteristics of this group are the largest bio-capacity deficit in comparison with the other 4 groups (Fig. 3 andSI Appendix, Table S12) and the largest area of land grabbedabroad as a percentage of its total area (SI Appendix, Table S10).

Intensive Food Producers and Exporters. The fourth group clusters8 vast countries from Oceania and the Americas with the largestintragroup variance (Fig. 1 and SI Appendix, Tables S8 and S9).This group exhibits high income and the largest GDP per capitaalongside the smallest population densities (SI Appendix, TableS10). Access to resources is high in these countries, and the agri-food system is focused largely on a model of intensive productionof cereals, fruit, meat, and biofuels dependent on large inputs ofpesticides and with very low rural and agricultural populations(Fig. 2 and SI Appendix, Table S11). However, organic agriculture(as a percentage of total agricultural area) scores high in this groupdue to Uruguay and the United States. Countries in this groupseem to be the “breadbasket of the world”: they show a large shareof food and agricultural exports while indicating limited food im-ports (Fig. 2 and SI Appendix, Table S11). In fact, some of them,such as Australia, Argentina, Canada, the United States, and mostrecently, Brazil dominate global food exports. This group alsoshows the largest financial support for agriculture (Fig. 2 and

Landgrabbed and undernourished:agricultural exporters but food importers

Intensive food producers and exporters

Diverse intensive producers

Overnourished agricultural importers

Least ecologically wealthy and landgrabbers

Not included in the classification

Fig. 1. World map with the countries colored according to the groups that emerged from the PCA and the HCA: purple is group 1, blue is group 2, green isgroup 3, yellow is group 4, red is group 5, and gray indicates the countries excluded from the analysis due to a lack of data.

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SI Appendix, Table S11). Food deficit is quite low, and the proteinsupply is high, consistent with the high level of energy adequacy(Fig. 2 and SI Appendix, Table S11). Another common feature ofcountries in this group is their large ecological footprints and

agricultural CO2 emissions as well as a large biocapacity thatsustains their large biocapacity reserves (Fig. 3 and SI Appendix,Table S12). Furthermore, they have the best records for all socialwellbeing indexes (Fig. 3 and SI Appendix, Table S12).

Fig. 2. Box plots of FSv indicators in the 5 clusters identified. Only indicators with statistically significant differences between the groups are represented.The 6 pillars of FSv are separated into (A) access to resources, (B) productive models, (C) commercialization, (D) food security and food consumption, (E)agrarian policies and civil society organizations, and (F) gender. The letters at the top of each box plot (A–D and combinations) correspond to the statisticallysignificant differences in the pair comparisons (more details are in SI Appendix).

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Overnourished Agricultural Importers. The fifth group is the mosthomogeneous group and includes 30 countries (SI Appendix, Fig. S4and Table S8), mostly in Europe (Fig. 1 and SI Appendix, Table S9),and it features the largest population densities, the second largestGDP per capita, and high income (SI Appendix, Table S10). Accessto resources is satisfactory in these countries (Fig. 2 and SI Ap-pendix, Table S11). Agriculture is quite intensive, with little ruraland agricultural populations, little presence of women who areeconomically active in agriculture, and a large use of fertilizers (Fig.2 and SI Appendix, Table S11). These are the largest importers ofagricultural products, however, with little imports and exports offood (Fig. 2 and SI Appendix, Table S11). People in these countriesare overall food secure but have a diet mostly based on a large

consumption of proteins (Fig. 2 and SI Appendix, Table S11). Thesecountries are in a biocapacity deficit because of the ecologicalfootprint of the built-up land and the croplands, instead showingthe lowest grazing footprint and agricultural water withdrawal butlarge CO2 agricultural emissions (Fig. 3 and SI Appendix, TableS12). These are the countries with the largest degree of globaliza-tion and net contribution of official development assistance forfood and agriculture as well as overall high levels of social wellbeing(Figs. 2 and 3 and SI Appendix, Tables S11 and S12).

DiscussionThe FSv indicator framework (38) used here to analyze agrifoodsystems from a social–ecological systems perspective (14) contributes

Fig. 3. Box plots of environmental sustainability (A) and social wellbeing (B) indicators in the 5 clusters identified. The letters at the top of each box plot (A–Dand combinations) correspond to the statistically significant differences in the pair comparisons (more details are in SI Appendix).

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to systematically and quantitatively assessing environmental, social,and economic relationships between countries within a globalizedworld. It allows us to measure progress through periodical moni-toring: ideally, countries should not be so easily clustered, and ifthey are, the groups should not show significant differences interms of their sociodemographic characteristics, environmentalsustainability, and social wellbeing. The current cluster might helpcountries to 1) be conscious of the impacts of their national agri-food policies in other countries and on their social–ecologicalsustainability; 2) evaluate the dependence of their food secu-rity, social wellbeing, and environmental sustainability on othercountries; and therefore, 3) allow governments to make sensiblechanges to agrifood policies to contribute to SDG2. In addition,these results might also provide guidance to development banksand other financial institutions.

Winners and Losers: Agrifood Debt. The International Council forScience critically pointed toward the internal inconsistency be-tween ecological sustainability and socioeconomic progression inthe SDG framework (39), and there is scientific quantitativeevidence about the nature and extent of this incompatibility ofsustainability and development (39–41). Our results provide ev-idence of the challenges to end hunger in a globalized agrifoodsystem, which is far from equitable from both socioeconomic andenvironmental perspectives. Certain countries, such as Australia,Brazil, Argentina, and those in Europe and North America, holda critical stake and should reduce overconsumption, while othercountries, such as most of Africa, would benefit from improvingtheir self-sufficiency. Consistent with previous research, our re-sults suggest that intertwined and nested material flows in globalagrifood systems result in interregional social inequities in thedistribution of both costs and benefits of producing, trading, andconsuming food, hence affecting social wellbeing, unevenly dis-tributing environmental impacts, and challenging environmentalsustainability.In line with the concept of “ecological debt,” which was coined

by academics in 1992 and further adopted and developed by civilsociety organizations and governments (42), the results presentedhere illustrate an agrifood debt (i.e., the interregional social–eco-logical disequilibria in the natural resources consumed, the envi-ronmental impacts produced, and the social wellbeing attained bypopulations in regions that play different roles within the global-ized agrifood system). Given that a substantial proportion of theworld’s 815 million people who are unable to meet daily foodneeds are food producers, such as small-scale farmers and fishers(11), our results are consistent with and strengthen the conclusionsof extensive previous research showing that food security is largelya matter of redistribution, entitlements, food access, and access toservices and means of production (22, 43). Globalization posescomplex tradeoffs for food system resilience across scales due tohigh social, economic, and ecological interconnectedness, trade-offs, and, hence, vulnerability (14). We suggest that this agrifooddebt, which has been poorly addressed to date, should be recog-nized, assessed, and monitored through 3 spotlights: 1) a severecontrast in diets and food security between regions, 2) a concernabout the role that international agrifood trade is playing in re-gional food security, and 3) a mismatch between regional bio-capacity and food security.

Nutritional and Environmental Contrasts in Diets and Food Securitybetween Regions. An unbalanced food system features a contrastbetween high rates of undernutrition (group 1) vs. overnutrition(in groups 4 and 5), leading to increasing overweight and obesity(11), which highlights the need to promote dietary changes inmany countries of the Global North (18, 28, 29, 44). Divergencesin diets are reflected by the differences in carbon footprints be-tween the groups: mean dietary carbon footprints vary from ca.0.7 kg CO2 eq. per capita per day for certain African countries (all

in group 1) to 4 kg CO2 eq. per capita per day for New Zealand,Australia, the United States, France, Austria, Argentina, andBrazil (all in groups 4 and 5) (18). If current crop production usedfor animal feed and other nonfood uses, such as biofuels (partic-ularly in the United States, China, Western Europe, and Brazil),were used for direct human consumption, ca. 70% more calorieswould be available, potentially satisfying the basic needs of 4 bil-lion people (26). Our results confirm that most countries with highnutritional quality show high ecological footprints, and therefore,changes in the diets in North America (group 4) and Europe(group 5) would entail the largest reductions in environmentalimpacts of the global agrifood system (18, 45, 46). The nutritiontransition, however, is also affecting the Global South (47, 48).Hence, concerns about nutrient density and public health must beincorporated into considerations around the environmental im-pacts of food and consequently, integrated into agricultural poli-cies (14, 18, 49). The point at which the higher carbon footprint ofsome nutrient-dense foods is offset by their higher nutritionalvalue is a priority area for additional research.Therefore, “doubling the agricultural productivity of small-scale

food producers,” as stated by SDG2, is per se not the way toeradicate hunger in a context where the world is already producingfood to feed 12 billion people (50, 51). On the contrary, only in-creasing agricultural productivity has led to reduced prices (ulti-mately harming farmers) and created health problems and theassociated costs (52). It might be even ecologically counterpro-ductive unless other agrifood policies are adopted, such as thereduction of the demand side and particularly, animal-sourcedfood in the diets of countries in groups 4 and 5 and of somecountries in group 3, the diminution of impacts of the supply chain,and the incentive of low-impact and crop-diversifying farmingsystems (14, 18, 29, 45, 46).

International Agrifood Trade, Food Security, and EnvironmentalSustainability. International trade plays an important role in foodsecurity (50), and the promotion and maintenance of certainlifestyles and diets rich in calories have been possible thanks to theglobal food trade (53); SDG2 states that “access to financial ser-vices, markets and opportunities to value addition” is needed.However, unless regulated and complemented with other policyinstruments, the global agrifood trade entails tradeoffs in terms ofsocial equity and environmental sustainability (54, 55). In fact,securing the food supply through imports occurs only in strong-enough economies (46, 53). In a globalized and financialized sys-tem, food tends to flow toward money and power, not towardhunger, and therefore, international agrifood trade can contributeto increase social inequality in the form of food insecurity by fa-cilitating food being exported/traded away from the hungry (51).The results presented here show how certain groups of countrieslose (groups 1 and 2) with respect to others (4, 5). In particular, thefirst group of countries (mostly in Africa) is a clear example of this:despite their large exports of agricultural products and the largestimports of food, undernutrition remains a critical constraint.More than one-fifth of global calorie production is exported,

mostly from countries in group 4 (the United States, Canada,Brazil, and Argentina) (56). Industrialized countries with highGDP per capita tend to be major net importers of biodiversity,while tropical countries, such as Argentina and Brazil, sufferhabitat degradation and biodiversity loss as a result of producingcrops for exports (57). Land use for export production is re-sponsible for 25% of the projected global extinctions and relatedbiodiversity loss (57, 58), ∼20% of global harvested croplandarea is devoted to export production (56), and most of the newcropland expansion is globally attributed to the production ofcrops for export (59). International food trade has been relatedto a virtual transfer of water (60), carbon (61), nitrogen (62), andphosphorus (63), while the environmental impacts of agriculturalproduction tend to remain in the producing countries (64).

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Mismatch between Regional Biocapacity and Food Security. Therehas been a strong decoupling between regional biocapacity andfood consumption. The global telecoupling (65) and increasinginterdependence among countries in regard to availability andaccess to food sources and the genetic resources supporting theirproduction (66) result in the increasing reliance of some regionson social and natural resources from other regions of the world,which also increases agrifood debt. A clear example of thisphenomenon is land grabbing, which is largely exerted by com-panies mostly from countries in groups 3 (the Middle East), 2(e.g., China), and 5 (e.g., Europe) on countries from group 1 (e.g.,Africa) (67, 68). For example, restrictions on agricultural pro-duction and changes in bioenergy demand have nurtured the de-pendence of the European Union (group 5) on the appropriationof biological productivity outside its boundaries, with increasingreliance on Latin America as the main supplier (59). Additionalevidence in that direction is related to food loss and waste: in-dustrialized Asia (China, India, and North Korea), Europe, NorthAmerica, and Oceania have the highest per capita carbon foot-print of food loss and waste, while sub-Saharan Africa has thelowest (69).

Limitations. The intricacy and complexity of the currently global-ized food system are impossible to fully disentangle with a purelystatistical exercise, like the one presented here. For instance,certain dimensions of FSv, such as power relations between dif-ferent actors within the agrifood system, cannot be easily assessedat a national scale. Nonetheless, new data sources that mightcontribute to the monitoring of FSv are continuously appearing,such as the Land Matrix project (https://landmatrix.org) for large-scale land acquisitions. A participatory, qualitative assessment withstakeholder collaboration could improve both the selection of in-dicators and the interpretation of results, for example, to be tai-lored at the national or regional levels, therefore also improvingthe usability of the knowledge generated (70). Clustering 150countries into 5 groups entails that intragroup variance remainslarge, therefore providing a relevant picture at a global scale butnot illustrating regional differences. Moreover, using the countryscale as a unit of analysis implies that environmental, social, andnutritional inequities cannot be accounted for. For example, dataon ethnic minorities, regional groups, indigenous populations,slum dwellers, and women aged 50 and over are rarely collected(20). A further constraint is the limited quality and/or availabilityof data: while data on economic indicators are widely availablefor most countries, data on environmental and social indicatorsof contested phenomena (e.g., land grabbing) are incompleteand of poor quality (20). However, given the international legiti-macy of the data sources (e.g., Food and Agriculture Organiza-tion’s Statistical Database [FAOSTAT], World DevelopmentIndicators [WDI]) and their broad use in previous scientific re-search, we are confident that data quality/availability issues donot undermine the main conclusions of this research.

ConclusionsIn the last 4 decades, there has been an intense debate about thebest policies needed to achieve what is currently stated in SDG2.Between the mid-1960s and the early 2000s, food availabilityimproved globally, and global per capita exports of agriculturalproducts almost doubled, but food self-sufficiency did not changesignificantly (53). The global population increased 2.5 times be-tween 1961 and 2016, while calorie production increased by morethan 4 times by 2013 (71). While the need to increase food pro-duction has been repeated like a mantra in many instances (6, 72),old policies focused on productivity, favoring agricultural indus-trialization, trade liberalization, privatization, and deregulation,have failed to end hunger (73). As this study corroborates, un-dernutrition is not only a matter of food availability and access (14,53). Instead, the eradication of hunger would be facilitated by a

redistribution of current consumption levels (74, 75). Furthermore,the challenges and responsibility for achieving SDG2 as well asother SDGs, still within planetary boundaries, are not evenly dis-tributed across the globe (6, 20). Providing quantitative agrifoodsystem metrics at the global scale using FSv indicators togetherwith other sociodemographic, social wellbeing, and environmentalindicators allows the identification of tradeoffs in environmentaland social justice within the global agrifood system and is currentlylargely ignored (76) but needed in order to comprehensively ad-dress SDGs. On a global scale, our results are consistent withprevious extensive research and with what we would expect to seeif wealthy countries are exporting environmental degradation toimport cheap food that is largely wasted and overconsumed:groups 4 and 5 (European and North American countries) shouldplay a prominent role in the transformation of the global agrifoodsystem toward one that is more environmentally sustainable andsocially equitable.There is no fundamental tradeoff between eradicating hunger,

achieving environmental sustainability (76), and social equity.However, for the achievement of SDG2 through transformational,socially fair, environmentally sustainable, and resilient food sys-tems, our results point to the following key wedges: biodiversityconservation through environmentally friendly agrifood practices(77), the reduction of agrifood waste (14), the regionalization offood distribution (14), and the adoption of healthy and sustainablediets (26). We need to make these steps fast enough to advanceSDG2 while preserving environmental sustainability and socialwellbeing.

Materials and MethodsData Collection. Ruiz-Almeida and Rivera-Ferre (38) compiled data on 97indicators for 223 regions (countries or officially recognized territories) be-tween 1961 and 2012 and followed a 6-step methodology to select the mostsuitable indicators according to data availability, quality, and representa-tiveness of the 6 categories of FSv (more detailed information is provided inSI Appendix, Fig. S1). Indicators were collected from open source databasescompiled by international organizations with recognized legitimacy, such aspublic institutions, agencies, and programs related to the United Nationsorganization (FAO, United Nations Development Program [UNDP], andUnited Nations Environmental Programme [UNEP]), international financialinstitutions (World Bank), and other international organizations (e.g., Or-ganization for Economic Co-operation and Development [OECD] and WorldTrade Organization [WTO]). Nine indicators were selected to describe thepillar of “access to resources,” 16 were selected for “productive models,” 8were selected for “commercialization,” 5 were selected for “food securityand consumption,” 3 were selected for “agrarian policies and civil societyorganization,” and 2 were selected for “gender.” For the objectives of thisresearch, we selected indicators following 4 main steps (SI Appendix, Fig. S3):1) we retrieved the historical data available from all indicators; 2) we se-lected the indicators for which the last data available referred to the time-frame between 2008 and 2012—for 223 countries or territories, there were92 indicators that fulfilled these criteria; 3) we debugged the database toreduce the extrapolation of data as much as possible and to avoid outliersdue to country or population size; and finally, 4) we incorporated extra datacharacterizing the bioregional location of the country, the social wellbeing,and the environmental sustainability of each country. The debuggingprocess, which included 4 steps, reduced the initial database to 150 coun-tries and 43 FSv indicators (SI Appendix, Fig. S3). In the final database, 200missing values (3.1% of the full database) were estimated through thenonlinear iterative partial least squares algorithm. To relate the state of FSvof the groups of countries with their state of social wellbeing and envi-ronmental sustainability, further indicator selection was conducted. Wescanned more than 200 indicators of social wellbeing and environmentalsustainability and selected 17 indicators for environmental sustainability (SIAppendix, Table S3) and 4 indicators for social wellbeing (SI Appendix, TableS4) based on the following criteria: 1) capacity to express the required in-formation, 2) availability of the information for a sufficient number ofcountries, 3) availability of the information for the selected timeframe (2008to 2012), and 4) veracity of the data according to internationally legitimizedsources. For the description of the demographic and economic contexts ofeach country, another 7 indicators were selected (SI Appendix, Table S6). Forthe bioregional characterization of the groups, we used a synthesis of the

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classification of the world ecoregions (i.e., the 26 categories included 14terrestrial, 7 inland water, and 5 marine ecoregions) (70) (SI Appendix,Table S7).

Data Analysis. Tests for the normality of the distribution of all 43 indicators ofFSv were performed. Only 1 indicator proved to follow a normal distributionand was standardized (n − 1). The indicators that did not follow a normaldistribution or show negative values were transformed through ln(x) orln(x + 1) when the indicator (x) showed a value equal to 0. The indicatorsthat did not follow a normal distribution and showed negative values werefirst rescaled (0 to 100) and then transformed through ln(x + 1).

For the identification of groups of countries, we carried out a PCA[covariance (n − 1)] based on the matrix of countries (observations) andindicators (variables). We followed the Kaiser criterion (eigenvalue >1) todetermine the significant number of components. To identify possible

groups of countries with similar values of FSv indicators, we carried out anHCA based on the Euclidean distance (percentage of distance similarity at a 95%level of confidence) and Ward’s agglomerative method (71) using the stan-dardized coordinates of the most significant factors of the PCA. Finally, tocharacterize each group resulting from the HCA in terms of ecoregions,socioeconomic characteristics, FSv, social wellbeing, and environmentalsustainability indicators, we performed Kruskal–Wallis and χ2 tests. Allstatistical analyses were run with XLSTAT69.

The characterization of the groups of countries clustered together inthe HCA was represented in a world map (Fig. 1) and 2 sets of box plots(Figs. 2 and 3).

Data Availability. The full database used, with all indicators, is available inDataset S1.

1. J. R. Porter et al., “Food security and food production systems” in Climate Change2014: Impacts, Adaptation, and Vulnerability. Part A: Global and Sectoral Aspects.Contribution of Working Group II to the Fifth Assessment Report of the Intergovern-mental Panel on Climate Change (Cambridge University Press, Cambridge, UK, 2014), pp.485–533.

2. M. G. Rivera-Ferre, M. Ortega-Cerdà, J. Baumgärtner, Rethinking study and man-agement of agricultural systems for policy design. Sustainability 5, 3858–3875 (2013).

3. C. Raudsepp-Hearne et al., Untangling the environmentalist’s paradox: Why is humanwell-being increasing as ecosystem services degrade? Bioscience 60, 576–589 (2010).

4. E. M. Bennett, Changing the agriculture and environment conversation. Nat. Ecol.Evol. 1, 18 (2017).

5. J. A. Foley et al., Solutions for a cultivated planet. Nature 478, 337–342 (2011).6. P. C. West et al., Leverage points for improving global food security and the envi-

ronment. Science 345, 325–328 (2014).7. P. Smith et al., “Agriculture, forestry and other land use (AFOLU)” in Climate Change

2014: Mitigation of Climate Change. Contribution of Working Group III to the FifthAssessment Report of the Intergovernmental Panel on Climate Change, O. Edenhoferet al., Eds. (Cambridge University Press, Cambridge, UK, 2014), pp. 811–922.

8. J. Rockström et al., Planetary boundaries: Exploring the safe operating space forhumanity. Ecol. Soc. 14, 32 (2009).

9. W. Steffen et al., Sustainability. Planetary boundaries: Guiding human developmenton a changing planet. Science 347, 1259855 (2015).

10. M. J. Chappell, L. A. LaValle, Food security and biodiversity: Can we have both? Anagroecological analysis. Agric. Human Values 28, 3–26 (2011).

11. FAO, The state of food and agriculture—leveraging food systems for inclusive ruraltransformation (2017). http://www.fao.org/3/a-i7658e.pdf. Accessed 26 November2019.

12. M. Tester, P. Langridge, Breeding technologies to increase crop production in achanging world. Science 327, 818–822 (2010).

13. H. C. J. Godfray et al., Food security: The challenge of feeding 9 billion people. Science327, 812–818 (2010).

14. M. E. Schipanski et al., Realizing resilient food systems. Bioscience 66, 600–610 (2016).15. P. J. Ericksen, Conceptualizing food systems for global environmental change re-

search. Glob. Environ. Change 18, 234–245 (2008).16. V. Vallejo-Rojas, F. Ravera, M. G. Rivera-Ferre, Developing an integrated framework

to assess agri-food systems and its application in the Ecuadorian Andes. Reg. Environ.Change 16, 2171–2185 (2016).

17. J. Loos et al., Putting meaning back into “sustainable intensification.” Front. Ecol.Environ. 12, 356–361 (2014).

18. A. Chaudhary, D. Gustafson, A. Mathys, Multi-indicator sustainability assessment ofglobal food systems. Nat. Commun. 9, 848 (2018).

19. UN, Sustainable development goals (2016). https://www.un.org/sustainabledevelopment/sustainable-development-goals/. Accessed 8 April 2016.

20. R. Swain, “A critical analysis of the sustainable development goals” in Handbook ofSustainability Science and Research, W. L. Filho, Ed. (Springer, 2018), pp. 341–355.

21. M. M. L. Lim, P. Søgaard Jørgensen, C. A. Wyborn, Reframing the sustainable devel-opment goals to achieve sustainable development in the anthropocene—A systemsapproach. Ecol. Soc. 23, 22 (2018).

22. V. Spaiser, S. Ranganathan, R. B. Swain, D. J. T. Sumpter, The sustainable developmentoxymoron: Quantifying and modelling the incompatibility of sustainable develop-ment goals. Int. J. Sustain. Dev. World Ecol. 24, 457–470 (2017).

23. FAO, Rome Declaration on world food security and world food summit plan of action(Rome, Italy) (1996). http://www.fao.org/3/w3613e/w3613e00.htm. Accessed 26 No-vember 2019.

24. D. Tilman, C. Balzer, J. Hill, B. L. Befort, Global food demand and the sustainableintensification of agriculture. Proc. Natl. Acad. Sci. U.S.A. 108, 20260–20264 (2011).

25. M. C. Hunter, R. G. Smith, M. E. Schipanski, L. W. Atwood, D. A. Mortensen, Agri-culture in 2050: Recalibrating targets for sustainable intensification. Bioscience 67,386–391 (2017).

26. S. J. Vermeulen, B. M. Campbell, J. S. I. Ingram, Climate change and food systems.Annu. Rev. Environ. Resour. 37, 195–222 (2012).

27. B. M. Campbell et al., Urgent action to combat climate change and its impacts (SDG13): Transforming agriculture and food systems. Curr. Opin. Environ. Sustain 34, 13–20(2018).

28. W. Willett et al., Food in the anthropocene: The EAT-lancet commission on healthydiets from sustainable food systems. Lancet 393, 447–492 (2019).

29. J. Poore, T. Nemecek, Reducing food’s environmental impacts through producers andconsumers. Science 360, 987–992 (2018).

30. M. Springmann, H. C. J. Godfray, M. Rayner, P. Scarborough, Analysis and valuation ofthe health and climate change cobenefits of dietary change. Proc. Natl. Acad. Sci.U.S.A. 113, 4146–4151 (2016).

31. D. Gustafson et al., Seven food system metrics of sustainable nutrition security. Sus-tainability 8, 196 (2016).

32. M. Nilsson et al., Mapping interactions between the sustainable development goals:Lessons learned and ways forward. Sustain. Sci. 13, 1489–1503 (2018).

33. FAO, Thirty-second FAO Regional Conference for Latin America and the Caribbean(Buenos Aires, Argentina) (2012). http://www.fao.org/3/mj764e/mj764e.pdf. Accessed26 November 2019.

34. P. Claeys, Human Rights and the Food Sovereignty Movement: Reclaiming Control(Routledge, London, UK, 2015).

35. L. Levidow, M. Pimbert, G. Vanloqueren, Agroecological research: Conforming - ortransforming the dominant agro-food regime? Agroecol. Sustain. Food Syst. 38,1127–1155 (2014).

36. O. De Schutter, Report of the special rapporteur on the right to food (A/HRC/25/57,New York) (2014). http://www.ohchr.org/EN/HRBodies/HRC/RegularSessions/Session25/Documents/A_HRC_25_57_ENG.DOC. Accessed 26 November 2019.

37. R. Patel, Food sovereignty. J. Peasant Stud. 36, 663–706 (2009).38. A. Ruiz-Almeida, M. G. Rivera-Ferre, Internationally-based indicators to measure agri-

food systems sustainability using food sovereignty as a conceptual framework. FoodSyst, 10.1007/s12571-019-00964-5 (2019).

39. ICSU ISSC, Review of Targets for the Sustainable Development Goals: The SciencePerspective (International Science Council, Paris, France, 2015).

40. D. I. Stern, M. S. Common, E. B. Barbier, Econonmic growth and environmental de-gredation: A critique of the environmental Kuznets Curve. Univ York 44, 24 (1994).

41. C. J. A. Bradshaw, X. Giam, N. S. Sodhi, Evaluating the relative environmental impactof countries. PLoS One 5, e10440 (2010).

42. G. Goeminne, E. Paredis, The concept of ecological debt: Some steps towards anenriched sustainability paradigm. Environ. Dev. Sustain. 12, 691–712 (2010).

43. A. Sen, Poverty and Famines: An Essay on Entitlement and Deprivation (ClarendonPress, Oxford, UK, 1981).

44. J. Dixon et al., The health equity dimensions of urban food systems. J. Urban Health84 (suppl. 3), i118–i129 (2007).

45. B. Bajželj et al., Importance of food-demand management for climate mitigation.Nat. Clim. Chang. 4, 924–929 (2014).

46. M. Berners-Lee, C. Kennelly, R. Watson, C. N. Hewitt, Current global food productionis sufficient to meet human nutritional needs in 2050 provided there is radical societaladaptation. Elem. Sci. Anth. 6, 52 (2018).

47. P. Amuna, F. B. Zotor, Epidemiological and nutrition transition in developing coun-tries: Impact on human health and development. Proc. Nutr. Soc. 67, 82–90 (2008).

48. N. P. Steyn, Z. J. McHiza, Obesity and the nutrition transition in Sub-Saharan Africa.Ann. N. Y. Acad. Sci. 1311, 88–101 (2014).

49. A. Drewnowski et al., Energy and nutrient density of foods in relation to their carbonfootprint. Am. J. Clin. Nutr. 101, 184–191 (2015).

50. P. D’Odorico, J. A. Carr, F. Laio, L. Ridolfi, S. Vandoni, Feeding humanity throughglobal food trade Earth’s Future. Earths Futur. 2, 458–469 (2014).

51. J. Ziegler, Betting on Femine: Why the World Still Goes Hungry (New Press, New York,NY, 2013).

52. T. G. Benton, R. Bailey, The paradox of productivity: Agricultural productivity pro-motes food system inefficiency. Glob. Sustain. 2, e6 (2019).

53. M. Porkka, M. Kummu, S. Siebert, O. Varis, From food insufficiency towards tradedependency: A historical analysis of global food availability. PLoS One 8, e82714(2013).

54. J. Sun et al., Importing food damages domestic environment: Evidence from globalsoybean trade. Proc. Natl. Acad. Sci. U.S.A. 115, 5415–5419 (2018).

55. M. Davis, Late Victorian holocausts: El Niño famines and the making of the ThirdWorld (Verso) (2001). https://books.google.es/books?id=2LjYUY3LHkoC&printsec=rontcover&hl=es&source=gbs_ge_summary_r&cad=0#v=onepage&q&f=false. Accessed22 October 2019.

56. G. K. MacDonald et al., Rethinking agricultural trade relationships in an era ofglobalization. Bioscience 65, 275–289 (2015).

57. A. Chaudhary, T. Kastner, Land use biodiversity impacts embodied in internationalfood trade. Glob. Environ. Change 38, 195–204 (2016).

26472 | www.pnas.org/cgi/doi/10.1073/pnas.1912710116 Oteros-Rozas et al.

Dow

nloa

ded

by g

uest

on

July

20,

202

1

58. A. Chaudhary, T. M. Brooks, National consumption and global trade impacts on

biodiversity. World Dev., 10.1016/j.worlddev.2017.10.012 (2017).59. T. Kastner et al., Cropland area embodied in international trade: Contradictory results

from different approaches. Ecol. Econ. 104, 140–144 (2014).60. J. A. Allan, Virtual water: A strategic resource global solutions to regional deficits.

Gr. Water 36, 545–546 (1998).61. M. E. Schipanski, E. M. Bennett, The influence of agricultural trade and livestock

production on the global phosphorus cycle. Ecosystems (N. Y.) 15, 256–268 (2012).62. J. N. Galloway et al., International trade in meat: The tip of the pork chop. Ambio 36,

622–629 (2007).63. T. Kastner, K.-H. Erb, S. Nonhebel, International wood trade and forest change: A

global analysis. Glob. Environ. Change 21, 947–956 (2011).64. P. Meyfroidt, E. F. Lambin, K. H. Erb, T. W. Hertel, Globalization of land use: Distant

drivers of land change and geographic displacement of land use. Curr. Opin. Environ.

Sustain. 5, 438–444 (2013).65. J. Liu, W. Yang, S. Li, Framing ecosystem services in the telecoupled Anthropocene.

Front. Ecol. Environ. 14, 27–36 (2016).66. C. K. Khoury et al., Increasing homogeneity in global food supplies and the implica-

tions for food security. Proc. Natl. Acad. Sci. U.S.A. 111, 4001–4006 (2014).67. W. Anseeuw, The rush for land in Africa: Resource grabbing or green revolution?

South African J Int Aff 20, 159–177 (2013).

68. S. Batterbury, F. Ndi, “Land-grabbing in Africa” in The Routledge Handbook of AfricanDevelopment, J. A. Binns, K. Lynch, E. Nel, Eds. (Routledge, London, UK, 2018), pp. 573–582.

69. FAO, The State of Food Insecurity in the World 2013. http://www.fao.org/publications/sofi/2013/en/. Accessed 26 November 2019.

70. W. C. Clark, L. van Kerkhoff, L. Lebel, G. C. Gallopin, Crafting usable knowledge forsustainable development. Proc. Natl. Acad. Sci. U.S.A. 113, 4570–4578 (2016).

71. N. McKeon, Food Security Governance: Empowering Communities, Regulating Cor-porations (Routledge, Abingdon, UK, 2015).

72. FAO, Global Agriculture towards 2050. High Lev Expert Forum-How to Feed World2050 (Food and Agriculture Organization, Rome, Italy, 2009), pp. 1–4.

73. R. Burdock, P. Ampt, Food sovereignty: The case and the space for community ledagricultural autonomy within the global strategic framework for food security andnutrition. J. Agric. Sci. 9, 1–18 (2017).

74. C. M. Pittelkow et al., Productivity limits and potentials of the principles of conser-vation agriculture. Nature 517, 365–368 (2015).

75. W. Easterly, The trouble with sustainable development goals. Current History 114,322–324 (2015).

76. D. P. van Vuuren et al., Pathways to achieve a set of ambitious global sustainabilityobjectives by 2050: Explorations using the IMAGE integrated assessment model.Technol. Forecast. Soc. Change 98, 303–323 (2015).

77. M. Altieri, Agroecology, small farms, and food sovereignty. Mon. Rev. 61, 102–113 (2009).

Oteros-Rozas et al. PNAS | December 26, 2019 | vol. 116 | no. 52 | 26473

SUST

AINABILITY

SCIENCE

Dow

nloa

ded

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uest

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July

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