Developing climate change impact metrics for agriculture

Abstract

We propose a framework for the analysis of the benefits of climate change policies on the agricultural sector, identifying biophysical factors, agricultural system characteristics, socio-economic data, and climate policy as key categories for analysis, and relating them to vulnerability criteria of agricultural systems in terms of their exposure, sensitivity, adaptive capacity, and synergy with mitigation strategies under climate change. Based on such a framework, a set of metrics is developed, comprised of variables that can be easily extracted from current impact assessment models and used to obtain consistent and comparable information on climate change impacts and benefits, in both monetary and non-monetary terms. Specifically, this work focuses on development of metrics for regional, national, and global scales, characterizing the short-term (20-30 years) and long-term (80-100 years) impacts of climate change on agriculture. The metrics, which include crop yield and variability, water stress indicators, production and land value, as well as a nutrition index for the number of people at risk of hunger, can help to identify risk thresholds and to evaluate policies related to adaptation. Finally, a number of improvements needed within current agronomic and economic models to address key uncertainties in assessing benefits of climate policies are discussed, with attention to the representation of the effects of climate extremes (heat waves, droughts, and floods), pest and disease interactions, and elevated CO2 on crops.