Abstract
Many approaches have been used to investigate climate change impacts on agriculture. However, several caveats remain in this field: (i) analyses focus only on a few major crops, (ii) large differences in yield impacts are observed between projections from site-based crops models and Global Gridded Crop Models (GGCMs), (iii) climate change impacts on livestock are rarely quantified, and (iv) several causal relations among biophysical, environmental, and socioeconomic aspects are usually not taken into account. We investigate how assumptions about these four aspects affect agricultural markets, food supply, consumer well-being, and land use at global level by deploying a large-scale socioeconomic model of the global economy with detailed representation of the agricultural sector. We find global welfare impacts several times larger when climate impacts all crops and all livestock compared to a scenario with impacts limited to major crops. At the regional level, food budget can decrease by 10 to 25% in developing countries, challenging food security. The role of land area expansion as a major source of adaptation is highlighted. Climate impacts on crop yields from site-based process crop models generate more challenging socioeconomic outcomes than those from GGCMs. We conclude that the agricultural research community should expand efforts to estimate climate impacts on many more crops and livestock. Also, careful comparison of the GGCMs and traditional site-based process crop models is needed to understand their major implications for agricultural and food markets.
Highlights
Studies dating to the 1980s have investigated climate change effects on agriculture, a sector highly exposed to the weather (Blanc and Reilly 2017). Porter et al (2014) find that climate 29 Page 2 of 21Climatic Change (2021) 166: 29 change has already affected agriculture, and is a likely threat to future food security
Given the complex interactions among regions through trade, and within the agricultural sector in terms of food consumption, crops, livestock, land use change, and land use emissions, we identify several metrics to quantify the potential economic importance of some of the major oversights we have seen in evaluating agricultural risks from climate change
The change in macroeconomic welfare measured as equivalent variation—the change in the total value of all goods consumed by households—is the broadest economic indicator of all effects and adjustments in the human activities needed to accommodate the impacts of climate changes on crop yields
Summary
Studies dating to the 1980s have investigated climate change effects on agriculture, a sector highly exposed to the weather (Blanc and Reilly 2017). Porter et al (2014) find that climate 29 Page 2 of 21Climatic Change (2021) 166: 29 change has already affected agriculture, and is a likely threat to future food security. Rosenzweig et al (2014) notes that site-based models consider the complexity of crop, soil, atmosphere, and management component interactions at the field level, while agro-ecosystem models deal with larger spatial scale simulations of the carbon and nitrogen dynamics, energy, soil, and water balance. Both approaches have been used to build Global Gridded Crop Models (GGCMs) that estimate crop yield impacts at the global scale
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