Assessing agricultural risks of climate change in the 21st century in a global gridded crop model intercomparison

Abstract

Here we present the results from an intercomparison of multiple global gridded crop models (GGCMs) within the framework of the Agricultural Model Intercomparison and Improvement Project and the Inter-Sectoral Impacts Model Intercomparison Project. Results indicate strong negative effects of climate change, especially at higher levels of warming and at low latitudes; models that include explicit nitrogen stress project more severe impacts. Across seven GGCMs, five global climate models, and four representative concentration pathways, model agreement on direction of yield changes is found in many major agricultural regions at both low and high latitudes; however, reducing uncertainty in sign of response in mid-latitude regions remains a challenge. Uncertainties related to the representation of carbon dioxide, nitrogen, and high temperature effects demonstrated here show that further research is urgently needed to better understand effects of climate change on agricultural production and to devise targeted adaptation strategies.food security | AgMIP | ISI-MIP | climate impacts | agriculture T he magnitude, rate, and pattern of climate change impacts on agricultural productivity have been studied for approximately two decades. To evaluate these impacts, researchers use biophysical process-based models (e.g., refs. 1-5), agro-ecosystem models (e.g., ref. 6), and statistical analyses of historical data (e.g., refs. 7 and 8). Although these and other methods have been widely used to forecast potential impacts of climate change on future agricultural productivity, the protocols used in previous assessments have varied to such an extent that they constrain crossstudy syntheses and limit the ability to devise relevant adaptation options (9, 10). In this project we have brought together seven global gridded crop models (GGCMs) for a coordinated set of simulations of global crop yields under evolving climate conditions. This GGCM intercomparison was coordinated by the Agricultural Model Intercomparison and Improvement Project (AgMIP; 11) as part of the Inter-Sectoral Impact Model Intercomparison Project (ISI-MIP; 12). In order to facilitate analyses across models and sectors, all global models are driven with consistent biascorrected climate forcings derived from the Coupled Model Intercomparison Project Phase 5 (CMIP5) archive (13). The objectives are to (i) establish the range of uncertainties of climate change impacts on crop productivity worldwide, (ii) determine key differences in current approaches used by crop modeling groups in global analyses, and (iii) propose improvements in GGCMs and in the methodologies for future intercomparisons to produce more reliable assessments.We examine the basic patterns of response to climate across crops, latitudes, time periods, regional temperatures, and atmospheric carbon dioxide concentrations [CO 2 ]. In anticipation of the wider scientific community using these model outputs and the expanded application of GGCMs, we introduce these models and present guidelines for their pract...

Global and regional health effects of future food production under climate change: a modelling study

“…Climate change leads to changes in temperature and precipitation which are expected to reduce global crop productivity, 5,15 lead to changes in food production and consumption, 6 and impact health by altering the composition of diets and, with it, the profile of dietary and weight-related risk factors and associated mortalities. 13 The results of this study indicate that even relative modest reductions in per-capita food availability could lead to changes in the energy content and composition of diets that are associated with significant, negative health implications.…”

“…First, there is general agreement about the negative impacts that climate change is expected to have on major staple crops, in particular at low latitudes and at high levels of warming. 5 However, the impacts that climatic changes could have on crops that are relatively less important based on their land coverage and production, but of increased importance for health, such as fruits and vegetables, would greatly benefit from further research. The current state of global crop modelling allowed us to directly model climate change effects on most major crops, such as groundnuts, maize, potatoes, rice, sorghum, soybeans, and wheat, 5,15 but the impacts on other crops had to be inferred from biophysical similarities.…”

“…5 However, the impacts that climatic changes could have on crops that are relatively less important based on their land coverage and production, but of increased importance for health, such as fruits and vegetables, would greatly benefit from further research. The current state of global crop modelling allowed us to directly model climate change effects on most major crops, such as groundnuts, maize, potatoes, rice, sorghum, soybeans, and wheat, 5,15 but the impacts on other crops had to be inferred from biophysical similarities. 6,15 Second, the economic responses of agricultural commodity markets to climatic shocks are subject to high uncertainty.…”

“…Future food production and consumption is expected to increase, driven by population and income growth and mediated by market responses, such as changes in prices and management practices. 33,34 Relative to that, climate change leads to changes in temperature and precipitation, which is expected to reduce global crop productivity, 5,15 and via market responses, lead to changes in management intensity, cropping area, consumption, and international trade. 6 From a health perspective, changes in food availability and consumption affect dietary and weigh-related risk factors associated with an increased incidence of non-communicable diseases and mortality, such as low fruit and vegetable consumption, [16][17][18] high red meat consumption, [18][19][20] and increased body weight.…”

“…2 The impacts on the food supply and food security may be one of the most important consequences of climate change due to the large number of people that may be affected. [2][3][4] Climate change impacts are expected to reduce the quantity of food harvested, 5 which could lead to higher food prices and reduced consumption, 6 and to an increase in the number of malnourished people. 7,8 However, the relationship between agriculture and health goes beyond issues of food security and caloric availability.…”