Citation: Ugwoke, B.; Tieman, R.; Mill, A.; Denkenberger, D.; Pearce, J.M. Quantifying Alternative Food Potential of Agricultural Residue in Rural Communities of Sub-Saharan Africa. Biomass 2023, 3, 138–162. https://doi.org/10.3390/ biomass3020010 Academic Editor: Lasse Rosendahl Received: 19 March 2023 Revised: 18 April 2023 Accepted: 26 April 2023 Published: 10 May 2023 Copyright: © 2023 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). Article Quantifying Alternative Food Potential of Agricultural Residue in Rural Communities of Sub-Saharan Africa Blessing Ugwoke 1 , Ross Tieman 2 , Aron Mill 2 , David Denkenberger 2,3 and Joshua M. Pearce 4, * 1 Energy Center Lab, Department of Energy Politecnico di Torino Italy, Via Paolo Borsellino 38, 1, 10138 Torino, Italy 2 Alliance to Feed the Earth in Disasters (ALLFED), Fairbanks, AK 99775, USA 3 Faculty of Engineering, University of Canterbury, Christchurch 8140, New Zealand 4 Department of Electrical & Computer Engineering, Ivey School of Business, Western University, 1151 Richmond St. N., London, ON N6A 3K7, Canada * Correspondence: joshua.pearce@uwo.ca Abstract: African countries have been severely affected by food insecurity such that 54% of the population (73 million people) are acutely food insecure, in crisis or worse. Recent work has found technical potential for feeding humanity during global catastrophes using leaves as stop-gap alter- native foods. To determine the potential for adopting agricultural residue (especially crop leaves) as food in food-insecure areas, this study provides a new methodology to quantify the calories available from agricultural residue as alternative foods at the community scale. A case study is performed on thirteen communities in Nigeria to compare national level values to those available in rural communities. Two residue utilization cases were considered, including a pessimistic and an optimistic case for human-edible calories gained. Here, we show that between 3.0 and 13.8 million Gcal are available in Nigeria per year from harvesting agricultural residue as alternative food. This is enough to feed between 3.9 and 18.1 million people per year, covering from 10 to 48% of Nigeria’s current estimated total food deficit. Keywords: alternative food; agricultural waste; sub-Saharan Africa; global catastrophic risk; existential risk 1. Introduction There is a risk of global hunger due to a confluence of regional catastrophes attributed to rising cases of conflicts, civil unrest, weather extremes and adverse climate, crop pests (e.g., desert locusts) and economic shocks, all of which were further exacerbated by the global coronavirus (COVID-19) pandemic [1,2]. Since 2015, the number of people battling acute hunger has been steadily rising, and it was estimated that in 2019 this figure had reached 135 million people (who were in crisis or worse, having reached IPC/CH Phase 3 or above), according to the Integrated Food Security Phase Classification (IPC) and the Cadre Harmonisé (CH), which estimate the populations of people in need of food, nutrition and livelihood assistance [2]. Some studies have attributed micronutrient deficiencies to difficulties learning; decreased academic productivity; some health issues, including chronic physical conditions such as asthma; and some mental health issues, such as anxiety, depression and substance use disorders, to the incidence of hunger [3–5]. Hunger has also been pegged as a global problem associated with suicide attempts [6]. Therefore, addressing this problem could translate to improvements in mental health worldwide, especially for adolescents [6,7]. In addition to these current problems, there is a risk of hunger caused by global catastrophic risks (GCRs). There are a number of catastrophes that could cause an abrupt 10% reduction in global food supply. These include abrupt regional climate change (~10 ◦ C drop in one decade, which has happened in the past) [8]; multiple breadbasket failures due to coincident extreme weather on multiple continents [9]; super-resistant crop pests that are Biomass 2023, 3, 138–162. https://doi.org/10.3390/biomass3020010 https://www.mdpi.com/journal/biomass