Abstract
The impacts of climate change on the food system are a key concern for societies and policy makers globally. Assessments of the biophysical impacts of crop productivity show modest but uncertain impacts. But crop growth is not the only factor that matters for the food production. Climate impacts on the labour force through increased heat stress also need to be considered. Here, we provide projections for the integrated climate-induced impacts on crop yields and worker productivity on the agro-economy in a global multi-sector economic model. Biophysical impacts are derived from a multi-model ensemble, which is based on a combination of climate and crop models, and the economic analysis is conducted for different socio-economic pathways. This framework allows for a comprehensive assessment of biophysical and socio-economic risks, and outlines rapid risk increases for high-warming scenarios. Considering heat effects on labour productivity, regional production costs could increase by up to 10 percentage points or more in vulnerable tropical regions such as South and South-East Asia, and Africa. Heat stress effects on labour might offset potential benefits through productivity gains due to the carbon dioxide fertilisation effect. Agricultural adaptation through increased mechanisation might allow to alleviate some of the negative heat stress effects under optimistic scenarios of socio-economic development. Our results highlight the vulnerability of the food system to climate change impacts through multiple impact channels. Overall, we find a consistently negative impact of future climate change on crop production when accounting for worker productivity next to crop yields.
Generated Summary
This research employs a recursive dynamic, multi-regional, multi-sectoral CGE model, named GRACE (Global Responses to Anthropogenic Changes in the Environment), to assess the economic implications of climate change impacts on crop production, including the effects of heat stress on worker productivity. The study utilizes a combination of climate and crop models to derive biophysical impacts, and conducts economic analysis under different socio-economic pathways. The methodology incorporates both heat-induced impacts on worker productivity and climate-induced impacts on crop productivity within a macroeconomic modeling framework. The study investigates the relevance of different types of scenario and modeling uncertainties, using two heat assessment metrics.
Key Findings & Statistics
- Considering heat effects on labor productivity, regional production costs could increase by up to 10 percentage points or more in vulnerable tropical regions such as South and South-East Asia, and Africa.
- The study considers two scenarios for changes in radiative forcing over the twenty-first century: RCP2.6 and RCP6.0.
- The climate projections and crop model simulations for the ISIMIP2b are used to derive scaling factors, which are implemented in the GRACE model.
- Future socioeconomic scenarios are modeled based on SSP1 and SSP4.
- The initial values in GRACE are calibrated using Version 9 of the Global Trade Analysis Project (GTAPv9) database.
- The study aggregated all countries and regions into 10 regions.
- Economic consequences of climate-induced impacts on crop yields and heat-induced impacts on worker productivity are calculated for the Radiative Concentration Pathways RCP2.6 and RCP6.0, two scenarios for changes in radiative forcing over the twenty-first century that attain 2.6 W/m² and 6.0 W/m² in 2100, respectively.
- By the mid-twenty-first century, global production of maize are moderate and uncertain.
- By the end-twenty-first century, global production of maize tends to decline under both RCPs because of a lower maize production in North America, South and South-East Asia, and Africa.
- Global production of both rice and soybeans tends to increase under both RCPs by the mid-twenty-first and end-twenty-first century, with the increases being more pronounced under RCP6.0.
- In the most heat-exposed and vulnerable regions, the increases in producer prices of crops lead to a decline in the production of livestock and food.
- Under RCP6.0, the economic cost of heat stress impacts on agricultural workers is substantially greater than under RCP2.6, especially by the end-twenty-first century.
- In Africa, a potential reduction in GDP could be up to 1.5% compared to the NoCC scenario.
- The choice of heat assessment metric substantially affects the cost of heat stress (Orlov et al. 2020).
Other Important Findings
- Climate impacts on the labor force through increased heat stress also need to be considered.
- Heat stress effects on labour might offset potential benefits through productivity gains due to the carbon dioxide fertilisation effect.
- Agricultural adaptation through increased mechanisation might allow to alleviate some of the negative heat stress effects under optimistic scenarios of socio-economic development.
- The study highlights the vulnerability of the food system to climate change impacts through multiple impact channels.
- The economic analysis is conducted for different socio-economic pathways.
- Considering heat effects on labor productivity, regional production costs could increase in vulnerable tropical regions.
- Our results highlight the vulnerability of the food system to climate change impacts through multiple impact channels.
- The analysis uses the Shared Socioeconomic Pathways (SSP) projections on the gross domestic product (GDP) and population growth.
- Economic costs of reduced worker productivity due to heat stress are found to be considerably high.
- Under RCP2.6, the economic responses by the mid-twenty-first century are approximately of the same order of magnitude as at the end-twenty-first century.
- Climate change-induced impacts on crop production are very uncertain and heterogeneous among regions, depending on the crop type, GCM, RCP, growing method, and crop model.
- In many regions, the impacts of heat stress result in higher producer prices.
- Developing countries are growing faster and their relative contribution to global GDP increases over time.
- The choice of heat assessment metric substantially affects the cost of heat stress.
Limitations Noted in the Document
- The study solely considers climate impacts on yields for four crops, while other agricultural crops could also be affected by climate change.
- Climate-induced impacts on crop yields are very uncertain.
- The analysis uses outputs from only four crop models and four global climate models.
- The implications of potential shifts in diets are not explored in this study.
- Proactive investments in mechanisation and R&D could further diminish the adverse impacts of heat stress.
- The effectiveness of shifting working hours has not been investigated.
- The epidemiological exposure-response relationship used in this study is also very uncertain.
- Crop yield losses tend to occur in the same period across different regions due to large scale teleconnections.
Conclusion
The research underscores the critical need to account for the effects of heat stress on worker productivity when evaluating the impacts of climate change on crop production. The study reveals that the adverse economic effects of heat stress could potentially offset the benefits of increased yields in many regions, particularly in South-East Asia and Africa, potentially leading to substantial economic losses. The economic consequences of climate-induced impacts on crop productivity are moderate because agriculture contributes a relatively small share of national income in most regions. The study emphasizes the relevance of socio-economic development pathways, as depicted by SSPs, in shaping the overall impact, with the uncertainty in the transient climate response to cumulative CO2 emissions being especially important. The research suggests that a higher climate sensitivity could lead to more pronounced welfare losses due to heat stress. Furthermore, the study highlights that the choice of heat assessment metrics significantly impacts the cost of heat stress, reinforcing the need for region- and sector-specific exposure-response functions for heat stress impacts. Overall, the study underscores that climate change impacts on crop production are very uncertain and heterogeneous among regions, the study also highlights the importance of considering heat stress on worker productivity. In the most heat-exposed and vulnerable regions, the increases in producer prices of crops lead to a decline in the production of livestock and food.