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Farming systems that support locally diverse agricultural production and high levels of biodiversity are in rapid decline, despite evidence of their benefits for climate, environmental health, and food security. Yet, agricultural policies, financial incentives, and market concentration increasingly constrain the viability of diversified farming systems. Here, we present a conceptual framework to identify novel processes that promote the emergence and sustainability of diversified farming systems, using three real-world examples where farming communities have found pathways to diversification despite major structural constraints. By applying our framework to analyze these bright spots in the United States, Brazil, and Malawi, we identify two distinct pathways—network and institutional—to diversification. These pathways emerge through alignment of factors related to social and ecological structure (policies, institutions, and environmental conditions) and agency (values, collective action, and management decisions). We find that, when network and institutional pathways operate in tandem, the potential to scale up diversification across farms and landscapes increases substantially.

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.

Global food calorie supply per person is more than 2900 kcal per day on average, but we have failed to ensure equitable access to these calories. Yet how uneven food access is within countries has remained poorly understood, as has the progress made over the past five decades on closing the access gap. Using publicly available data, we developed a theoretically-grounded statistical model to estimate the cross-national relationship between average per capita expenditure and per capita food availability and used this to estimate within-country access to food for income deciles in 135 countries. We find that, from 1961 to 2013, despite between-country inequality declining by 48% (decline in Gini coefficient from 0.15 to 0.078), within-country inequality in food access increased by 25% for the countries in our study sample (Gini coefficient increased from 0.088 to 0.111). Furthermore, we find that the poorest 10% of the population in the majority of countries in South Asia, South East Asia and Africa—home to the majority of the world's food insecure—continue to access their calories primarily from staple foods and have extremely limited access to nutrient-dense foods, resulting in inequality in access to nutrient-dense foods that is even greater than inequality in access to total calories (within-country Gini coefficient of 0.2). These results strongly support continued investments in social safety nets targeted at the poorest half of the income distribution to swiftly reduce inequality in food access, and proactive programs that help vulnerable households build assets to sustain themselves through future food crises.

The widely reported claim that smallholders produce 70–80% of the world’s food has been a linchpin of agricultural development policy despite limited empirical evidence. Recent empirical attempts to reinvestigate this number have lacked raw data on how much food smallholders produce, and have relied on model assumptions with unknown biases and with limited spatial and commodity coverage. We examine variations in crop production by farm size using a newly-compiled global sample of subnational level microdata and agricultural censuses covering more countries (n=55) and crop types (n=154) than assessed to date. We estimate that farms under 2ha globally produce 28–31% of total crop production and 30–34% of food supply on 24% of gross agricultural area. Farms under 2ha devote a greater proportion of their production to food, and account for greater crop diversity, while farms over 1000ha have the greatest proportion of post-harvest loss.

From COVID-19 to the war in Ukraine, virtual models could inform global food policy before emergencies unfold.

AbstractTimely monitoring of crop production using a remote sensing-based approach offers promise toward enhancing food security. Statistical models developed using satellite data typically employ a single vegetation index from a single sensor for yield estimation. With the increasing availability of satellite datasets, there is now an opportunity to investigate the potential of available vegetation indices from different sensors in estimating yields. The key objective of this study was to develop a best-performing satellite-based yield model for the Canadian Prairies for wheat, barley, and canola, trained using municipality-level data from 2009 to 2019. We tested the statistical performance of models built using (a) indices from different sensors (Landsat and Sentinel-2), (b) indices sensitive to different yield properties, and (c) single versus multiple vegetation indices. Results showed Landsat-NDWI as the best performing single-index across all indices and sensors for each crop. Sentinel-2-EVI performed best for wheat and canola and Sentinel-2-SR for barley; but these models were built using only 4 years of data. We found that best-performing single-index models recorded similar predictive accuracy as multi-index models during model validation. The results from this work suggest that satellite-based yield estimation can be improved by selecting the right index related to different crop properties.

There is widespread concern that the risk of food shocks — sudden disruptions to food supply — is increasing. It emerges that a city’s vulnerability to food shocks can be reduced by diversifying its supply chains.

Letter to the Editor

Food security is uncertain under future climate change, but is there a threat of food system collapse? Now research assesses the probability of weather hazards occurring at the same time in the world’s major breadbaskets and reveals that the weather-related component of this risk could be increasing.

Letter to the Editor