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Environ. Res. Lett. 00 (2015) 000000

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Scenarios for the risk of hunger in the twenty ﬁrst century using
shared socioeconomic pathways

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9 November 2014

Q1

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23 December 2014
PUBLISHEDDD MM 2014

Tomoko Hasegawa, Shinichiro Fujimori, Kiyoshi Takahashi and Toshihiko Masui
Center for Social and Environmental Systems Research, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki 3058506, Japan
E-mail: hasegawa.tomoko@nies.go.jp
Keywords: risk of hunger, SSP, CGE model, socioeconomic scenario

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Abstract
Shared socioeconomic pathways (SSPs) are being developed internationally for cross-sectoral assessments of climate change impacts, adaptation, and mitigation. These are ﬁve scenarios that include
both qualitative and quantitative information for mitigation and adaptation challenges to climatechange. In this study, we quantiﬁed scenarios for the risk of hunger in the 21st century using SSPs, andclariﬁed elements that inﬂuence future hunger risk. There were two primary ﬁndings: (1) risk of hunger in the 21st-century greatly differed among ﬁve SSPs; and (2) population growth, improvement in
the equality of food distribution within a country, and increases in food consumption mainly driven
by income growth greatly inﬂuence future hunger risk and are important elements in its long-term
assessment.

1. Introduction

Q2

Models that integrate changing climate conditions
with agricultural and economic models can assess thelikely impact of climate change on future foodsupplies. However, although these studies are useful,they provide limited insight into understanding thefuture of food security, given that social welfare,
distribution, political and institutional effectiveness,among other factors, come into play (Barrett 2010,
Godfray et al 2010). Nelson et al (2014) found that (1)population and gross domestic product (GDP) weresigniﬁcant in determining the impact of climatechange on food consumption and child malnutrition,and (2) that climate change would increase thenumber of malnourished children regardless of population and GDP assumptions, with the largest impact
in low-income countries. Schmidhuber and Tubiello(2007) found that the impact of climate change
strongly depended on population and GDP, andwould be particularly serious in sub-Saharan Africa.
However, these studies were based on the Special
Report on Emissions Scenarios (SRES) (Nakicenovicet al 2000) and past climate data (Meehl et al 2007), so
impact assessments must be updated.

© 2015 IOP Publishing Ltd

Hasegawa et al (2014) analyzed the effects ofautonomous adaptations in crop production to reducerisk of hunger using the latest climate data (Tayloret al 2011) with a new scenario framework (introducedbelow). They found that these adaptations wouldreduce risk of hunger regardless of population, GDP,and climate conditions. While the above studies did
not consider socioeconomic factors, van Ruijven et al(2013) showed that socioeconomic indicators should
be considered, and expected that explicit treatment ofthese additional indicators would accelerate climateresearch. For example, Kii et al (2013) used inequalityof domestic food distribution as a socioeconomic indicator when assessing food consumption. They foundthat average food consumption would be higher withlower inequality in food distribution.
A new, interdisciplinary scenario framework has
recently been designed for climate change research(O’Neill et al 2014, van Vuuren et al 2014). It consistsof two key elements: the magnitude and extent of climate change and climate policy (as characterized by
the representative concentration pathways (RCPs));
and a set of alternative trajectories of future globaldevelopment (described by shared socioeconomicpathways (SSPs)). The framework enables us to separate these elements to study the effects of climate