AgMIP Two-Track Science Approach

The AgMIP Two-Track Science Approach addresses Model Intercomparison and Improvement (Track One) and Climate Change multi-model Assessment (Track Two). Both tracks are facilitated by global studies and workshops that focus on particular crops and on global analyses and will lead to critically important outputs, each targeting outcomes that contribute to AgMIP objectives.

The global crop studies are organized to test multiple sites across the agricultural regions worldwide with as many crop models as possible for each individual crop. Participants at the regional workshops conduct analyses at field-to-regional scales and include both crop and economic model intercomparisons and improvement activities, as well as simulations with guided climate sensitivity tests and climate change scenarios.

    Rosenzweig et al., 2013.

To examine the full range of climate change impacts on agriculture, both biophysical and economic aspects need to be considered and combined (Hillel and Rosenzweig, 2011). Methodologies for assessing the biophysical effects of climate on crop yield include statistical models (e.g., Schlenker et al., 2006; Lobell and Burke, 2010) and process-based dynamic crop growth models (e.g., Keating et al., 2003; Brisson et al., 2003; Jones et al., 2003; van Ittersum and Donatelli, 2003; Challinor et al., 2004). For simulating the combined biophysical and economic effects of climate change on agriculture, reduced form statistical models have been used (e.g., Mendelsohn et al., 1994) as well as internally or externally coupled biophysical and economic simulation models designed for integrated assessment of economic, technological, policy, and environmental changes at regional or global scales (e.g., Rosenzweig and Parry, 1994; Fischer et al., 2002; Hermans et al., 2010; Nelson et al, 2010).

Track One: Model Intercomparison and Improvement

Global Studies.

Track One includes activities for model intercomparisons and improvement and for calibrating and evaluating models for use in different regions and for different crops. Teams are organized to compare and improve models for specific crops and regions and for regional and global economic models. Global teams work on a crop-by-crop basis to intercompare crop models for accuracy and variability of model responses to climatic, management, soil, and growth-influencing factors.

Workshops facilitate model improvements by participating crop model groups through assembling leading experimentalists who can provide the best knowledge about crop responses to climate, soil, and management factors and can provide the best scientific data for improving the models. This includes, for example, assembling scientists responsible for experiments on CO2, temperature, water, and N responses.

In the process of testing multiple crop models against such data, the model developers learn from the data-comparison and each other. Economic modeling teams work with crop modeling teams on a parallel set of activities, including the design procedures to aggregate crop model simulations to appropriate spatial scales, the design of representative agricultural pathways (RAPs) to be used for both crop and economic modeling runs, and uncertainty analysis. The economic teams implement model runs based on a specified set of crop model outputs and RAPs for intercomparison and analysis. These model runs are also be used by regional teams to define price scenarios for their analyses.

Regional Workshops.

Meetings designed to contribute to the goals of Track One and to simultaneously build capacity of scientists in the regions. The workshop participants include regional experts as well as members of model development groups to work on specific crops, climate sensitivity and climate change scenarios, and on economic model data and analyses. A target number of major crops is selected for each region.

Participants at the workshop include regional contributors with expertise in agronomy, crop modeling, climate science, economic modeling and analyses, and information technologies as well as members of the AgMIP teams (Crop Modeling, Economic Modeling, Climate Scenarios, and Information Technology Teams).

See Workshop Reports here.

Track Two: Multi-Model Assessment

In Track Two, AgMIP conducts assessments of climate change effects on food production and food security at regional to global scales, including analyses of adaptation and mitigation measures over a range of agricultural futures designated Representative Agricultural Pathways (RAPs). AgMIP will produce a database of multiple crop model results from regional sentinel sites (see Crop Modeling Protocols) to create an input dataset for use in regional and global agricultural economic models. The regional assessments, facilitated by the regional workshops, make use of the best available methods for aggregation across scales and characterization of uncertainty for use by local to regional decision and policy makers.

The economic models are used for assessment of world trade and economic impacts of different climate scenarios and agricultural pathways as well as impacts on food security. A fast track use of the aggregated regional datasets is to enable analyses for the IPCC AR5. Economic modelers from the International Food Policy Research Institute (IFPRI), Global Trade Analysis Project (GTAP), Terrestrial Ecosystem Model (TEM), IIASA Basic Linked System (BLS), and others have expressed interest in running their agricultural economic models with the AgMIP input dataset. The goal is for multiple economic models to use the same input dataset and RAPs so that model results regarding the effects of climate change on global agricultural production and trade, as well as food security can be rigorously compared. As more sites and models result from the regional activities, these will be added into the AgMIP datasets for simulations by the global agricultural economic models.

Track Two utilizes the regional aggregation methods for both inputs and outputs developed in the regional workshops and in conjunction with the economic modelers. This work will integrate the regional results to facilitate simulations and transdisciplinary analyses across scales. The economic protocols detailed below will be used to guide the work of Track Two. Results from the AgMIP climate scenarios and multiple model runs will also be analyzed to gauge related uncertainties.

These efforts will be harmonized with current efforts of IFPRI, GTAP, and other groups. The regional analyses will contribute to the global analyses, which will be coordinated by the Leadership Team.