Coordinating AgMIP data and models across global and regional scales for 1.5°C and 2.0°C assessments

Abstract

The Agricultural Model Intercomparison and Improvement Project (AgMIP) has developed novel methods for Coordinated Global and Regional Assessments (CGRA) of agriculture and food security in a changing world. The present study aims to perform a proof of concept of the CGRA to demonstrate advantages and challenges of the proposed framework. This effort responds to the request by the UN Framework Convention on Climate Change (UNFCCC) for the implications of limiting global temperature increases to 1.5°C and 2.0°C above pre-industrial conditions. The protocols for the 1.5°C/2.0°C assessment establish explicit and testable linkages across disciplines and scales, connecting outputs and inputs from the Shared Socio-economic Pathways (SSPs), Representative Agricultural Pathways (RAPs), Half a degree Additional warming, Prognosis and Projected Impacts (HAPPI) and Coupled Model Intercomparison Project Phase 5 (CMIP5) ensemble scenarios, global gridded crop models, global agricultural economics models, site-based crop models and within-country regional economics models. The CGRA consistently links disciplines, models and scales in order to track the complex chain of climate impacts and identify key vulnerabilities, feedbacks and uncertainties in managing future risk. CGRA proof-of-concept results show that, at the global scale, there are mixed areas of positive and negative simulated wheat and maize yield changes, with declines in some breadbasket regions, at both 1.5°C and 2.0°C. Declines are especially evident in simulations that do not take into account direct CO effects on crops. These projected global yield changes mostly resulted in increases in prices and areas of wheat and maize in two global economics models. Regional simulations for 1.5°C and 2.0°C using site-based crop models had mixed results depending on the region and the crop. In conjunction with price changes from the global economics models, productivity declines in the Punjab, Pakistan, resulted in an increase in vulnerable households and the poverty rate.This article is part of the theme issue 'The Paris Agreement: understanding the physical and social challenges for a warming world of 1.5°C above pre-industrial levels'.

Global wheat production with 1.5 and 2.0°C above pre‐industrial warming

“…Baseline (1980–2010) climate data for each wheat modeling site come from the AgMERRA climate dataset, which combines observations, reanalysis data, and satellite data products to provide daily climate forcing data for agricultural modeling (Ruane, Goldberg, & Chryssanthacopoulos, ). Climate scenarios here are consistent with the AgMIP Coordinated Global and Regional Assessments (CGRA) 1.5 and 2.0°C World study (Rosenzweig et al, ; Ruane, Antle, et al, ; Ruane, Phillips, et al, ), utilizing the methods summarized below and in the Supporting Information Appendix S1 and fully described by Ruane, Phillips, et al (). Climate changes from large (83–500 member for each model) climate model ensemble projections of the +1.5 and +2.0ºC scenarios from the Half a Degree Additional Warming, Prognosis and Projected Impacts project (HAPPI; Mitchell et al, ) are combined with the local AgMERRA baseline to generate driving climate scenarios from five GCMs (MIROC5, NorESM1‐M, CanAM4 [HAPPI], CAM4‐2degree [HAPPI], and HadAM3P) for each location (Ruane, Phillips, et al, ).…”

“…The shaded areas show the distribution of the data related to CO 2 impacts in the 1.5 and 2.0°C worlds, as well as peculiarities in the definition of CO 2 concentrations in HAPPI. CO 2 is also identified as the primary cause of increases between 1.5 and 2.0°C worlds in Rosenzweig et al (2018). Our study focused on stabilized 1.5 and 2.0°C worlds rather than the transient pathways that get us there, which will include gradually increasing CO 2 concentrations even as some scenarios include an overshoot in global mean temperatures.…”

Global Response Patterns of Major Rainfed Crops to Adaptation by Maintaining Current Growing Periods and Irrigation

“…Crop models allow for the conducting of virtual experiments to study the complex and interdependent biophysical effects of atmosphere and soil processes on crop growth and yield formation. As such, they are widely applied tools for the analysis of climate change impacts on agriculture and play a fundamental role in integrated assessment studies (Rosenzweig et al, ). Here we present the first spatially explicit global study of the adaptation potential of the major staple crops to local temperature increase in rainfed systems.…”

The GGCMI Phase II experiment: global gridded crop model simulations under uniform changes in CO<sub>2</sub>, temperature, water, and nitrogen levels (protocol version 1.0)

“…GGCMI Phase II compares simulations across a set of inputs with uniform perturbations to historical climatology, including CO 2 , temperature, precipitation, and applied nitrogen (collectively referred to as "CTWN"), as well as adaptation to shifting growing seasons. The CTWN experiment is inspired by AgMIP's Coordinated Climate-Crop Modeling Project (C3MP Ruane et al, 2014;McDermid et al, 2015) and 25 contributes to the AgMIP Coordinated Global and Regional Assessments (CGRA) Rosenzweig et al, 2018).…”