Agronomic approach to understanding climate change and food security

Authors: O'Brien, Peter; KRAL-O'BRIEN, KATHERINE - North Dakota State University; HATFIELD, JERRY - Retired ARS Employee

Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/15/2021
Publication Date: 5/30/2021
Citation: O'Brien, P.L., Kral-O'Brien, K.C., Hatfield, J.L. 2021. Agronomic approach to understanding climate change and food security. Agronomy Journal. https://doi.org/10.1002/agj2.20693.
DOI: https://doi.org/10.1002/agj2.20693

Interpretive Summary: The United States is a global leader in agricultural production and food exports, and it plays a crucial role in global food security. Climate change has the potential to affect the capacity of US agricultural systems to continue to meet food demand, especially as the world population continues to grow. The discussion about how climate change will affect agriculture is often framed around consequences in the future, e.g., how will climate change affect agriculture in 2050 or 2100? However, we review evidence that climate change is already affecting agriculture across the US, and it may have the potential to dramatically affect food production and, consequently, food security in the next decade. The effects of climate change are not uniform, as the combined interactions of increased CO2 levels with altered precipitation and temperature regimes create different conditions across the agricultural regions of the US. Thus, we propose the concept of yield gaps to quantify the effects of climate change. Yield gaps are the difference between the potential yield of a crop (PY), the maximum possible yield of a crop assuming no limitations of growth, and farm yield (FY), the observed yield from an actual farming operation. Evidence suggests that PY is increasing due to genetic advances and improved management efficiency, but FY is not increasing as fast as PY, thereby leading to larger yield gaps. The increase in yield gaps may be attributed to climate change exacerbating land degradation that is already occurring due to tillage, simplified crop rotations, and excessive chemical applications. We propose that a framework including genetics, environmental factors, and management practices (G x E x M) is a potential path towards reducing the yield gaps. Using the G x E x M framework in conjunction with yield gaps may be useful in guiding both researchers and farmers in developing strategies for climate change adaptation and mitigation, which is critical to maintaining a sustainable, resilient food production system.

Technical Abstract: Climate impacts agricultural productivity and the distribution of crops grown around the world. Because the United States is a leader in food exports, climate change impacts in the US have the potential to disproportionately affect the global food supply. Further, the global food supply is already stressed as a result of population growth. Given the change in temperature, precipitation, and carbon dioxide occurring now and expected into the future, the potential for agroecosystems to produce sufficient quantities of food to meet world demand is in question. To address this question, the concept of yield gaps, as the difference between potential yield (PY) and farm yield (FY) provides a framework for the evaluation of progress in production. Across all crops there have been increases in both PY (breeding, technological advances) and FY (implementation of improved genetic resources and management practices); however, climate change threatens to diminish those advances due to temperature stresses and more uncertain precipitation patterns. Climate change will increase the yield gap in the future and will be increased by the degradation of the soil resource due to climate and management. Modern agricultural systems must adapt to become more resilient, and the tools to this adaptation involve genetics, environmental monitoring, and evolving management practices. This framework of Genetic x Environment x Management (G x E x M) interactions has the potential to facilitate development of effective strategies to achieve food security. However, progress can only begin once agricultural systems are managed from a more holistic view of providing both quantity and quality of a more diverse mixture of agricultural crops that will provide sustainability, equity, nutrition, and a secure food future.