In a recent study published in the journal Scientific Reports, researchers used large-scale computational models to explore the impacts of heat and water stress on global food security and production.
The findings suggest that by 2050, global food production could fall by up to 14 percent and up to 1.36 billion more people could become severely food insecure, highlighting the crucial importance of addressing water and heat stresses in climate change policies.
People with acute food insecurity (percentage of population coverage) by region in 2050 compared to 2020. Model output. Map generated using ArcGIS Pro 3.3 (https://www.esri.com). Study: Global impacts of heat and water stress on food production and acute food insecurity.
background
Previous research has revealed that climate change poses significant threats to the world’s food production systems, which are highly dependent on ecosystems and water resources. These threats include disruptions to the hydrological cycle, such as extreme weather events and groundwater depletion, and their impacts vary from region to region.
Significant risks identified include water and heat stress to food production worldwide, exacerbated by increasing water withdrawals in different sectors, especially irrigated agriculture.The Integrated Assessment Model (IAM) highlights increasing food insecurity due to population growth, dietary changes and agricultural efficiency, especially under the scenario of regional conflict and inequality, i.e. two common socio-economic pathways (SSPs).
Moreover, mitigation efforts to reduce emissions often lead to increased production costs and food prices, particularly affecting low-income regions. However, these IAMs lack detailed transparency on damage functions and temporal dynamics, requiring more comprehensive models to assess the complex interdependencies of global food security.
About the Research
The researchers used an intertemporal computable general equilibrium (CGE) model to project the impacts of climate change on global food production and food security by 2050. Unlike many IAMs, this model explicitly integrates agricultural dynamics, such as changes in irrigation and damage from climate change, into the model.
This approach allows the researchers to simulate feedbacks across multiple steps simultaneously. The model takes into account international trade, dynamic changes in water resources and water availability for agricultural production. It also takes into account factors such as heat stress that affect labor productivity.
The study used demographic data from SSP scenarios, namely SSP2 (where current social, economic and technological trends continue without any major deviations) and SSP3 (where regional conflicts, nationalism and other barriers to cooperation and trade dominate).
They also synthesized two Representative Concentration Pathways (RCPs): RCP4.5 (a scenario in which greenhouse gas emissions stabilise by the middle of the century and then decline) and RCP8.5 (a high-emissions scenario that assumes greenhouse gas emissions continue to increase throughout the 21st century).
The model then produced three projections: SSP3-RCP8.5, SSP2-RCP4.5, and SSP2-RCP8.5.
These projections used data from 141 countries, aggregated across 30 regions and 30 commodity sectors, to quantify the impacts of heat and heat stress on agricultural products and estimate the number of additional people facing severe food insecurity by 2050.
Projections are based on gigacalore (GCal) measures of food production and quantification of food insecurity using the Food Insecurity Experience Scale.
Investigation result
The study projected the impact of climate change on global food production and food security under three scenarios: SSP2-RCP4.5, SSP2-RCP8.5, and SSP3-RCP8.5. The results showed that global food production in 2050 could decrease by 6%, 10%, and 14%, respectively.
These declines in food production, measured in GCal, reflect a significant reduction in nutritional energy supplies. Specifically, global food production could fall from 9.75 million GCal in 2020 to 9.2 million, 8.8 million and 8.4 million GCal under the three scenarios, respectively.
The magnitude of declines varies by region, with more pronounced declines in parts of Africa, Australia, and South America. For example, under SSP3-RCP8.5, food production could decline by up to 19.4% in Central America and 22.4% in China.
The number of people facing severe food insecurity is expected to increase significantly, by 556 million, 935 million, and 1.36 billion under SSP2-RCP4.5, SSP2-RCP8.5, and SSP3-RCP8.5, respectively.
Africa is particularly threatened by large declines in food production and population growth. Projections also suggest large increases in food prices and changes in trade flows, with net food exporters such as China becoming food importers by 2050 and increasing imports from less water-scarce regions.
Reduction (percentage range) in regional food production from irrigated agriculture due to heat and water stress in 2050 compared to 2020. Model output. Map generated using ArcGIS Pro 3.3
Conclusion
The study concludes that heat and water stress will have significant impacts on global food production and food security, predicting large declines in food production and a sharp increase in severe food insecurity by 2050.
Unlike previous studies, this study quantifies these impacts with a detailed focus on irrigation, commodity prices, resource allocation and trade effects. The model highlights that climate change will exacerbate existing vulnerabilities in food systems and lead to severe regional disparities.
The strengths of this study are its comprehensive integration of heat and water stress drivers and its forward-looking approach that takes into account global trade trends, but it also has limitations, such as focusing only on blue water sources and not considering the impacts of water stress on rain-fed croplands.
Future research should expand the study to include the impacts of green water (stormwater) and further explore technological advances and policy interventions to mitigate these impacts.
The study highlights the urgent need to transform food systems to make them more resilient to climate change, reduce greenhouse gas emissions and sustainably manage water resources.
