Climate-agriculture interactions and needs for policy making

Research exploring climate change interactions with agriculture has evolved from simplistic “delta T” simulation experiments with crop models to work highlighting the importance of climate variability and extreme events, which characterized the negative impacts possible if no adaptation occurred. There soon followed consideration of socioeconomic factors allowing for adaptive strategies that are likely to mitigate the worst case outcomes originally projected. At the same time, improved understanding of biophysical feedbacks has led to a greater recognition of the role that agriculture plays in modifying climate, with a great deal of attention recently paid to strategies to enhance carbon sequestration in agricultural systems. Advances in models of biogeochemical cycling applied to agronomic systems have allowed for new insights into greenhouse gas emissions and sinks associated with current, conventional farming systems. Yet this work is still relatively simplistic in that it seldom addresses interactions between climate dynamics, adoption of mitigation strategies, and feedbacks to the climate system and the surrounding environment. In order for agricultural policy to be developed that provides incentives for appropriate adaptation and mitigation strategies over the next 50 years, a systems approach needs to be utilized that addresses feedbacks and interactions at field, farm and regional scales in a broader environmental context. Interactions between carbon and climate constraints on the one hand, and environmental impacts related to water, nutrient runoff, and pest control all imply a transformation of farming practices that is as of yet not well defined. Little attention has been paid to studying the implications of “alternative” farming strategies such as organic systems, intensive rotational grazing of livestock, or increases in the perennial component of farmscapes, all of which may be necessary responses to energy and other environmental constraints over the coming century, interacting with a changing climate. Examples of interactions that need further exploration include the degree to which increases in soil organic matter to enhance carbon sequestration will improve system resilience and help mitigate the effects of an increase in climate variability, and how we can optimize the role of below-ground microbial communities in methane and nitrous-oxide emissions and sinks as well as in nutrient cycling and plant-water relations. These and other key areas where agroecosystem research is needed to advance policy will be discussed.