CANCELLED - Food productivity in the US: a synthetic analysis of crop productivity in response to climate change during 1951-2050

Background/Question/Methods

Agriculture ecosystem plays an important role in climate change mitigation and adaptation in the context of multiple environmental changes. It is essential to consider the combination effects of climate variability/change and other environmental factors on food production and the impacts of agriculture ecosystem on climate warming potential when adopting a specific adaptation strategy at local or regional level. In this study, we applied a process-based ecosystem model (the agricultural module of Dynamic Land Ecosystem Model-DLEM) which fully couples crop growth and biogeochemical/hydrological cycles in terrestrial ecosystems; and developed regional and gridded database in the US during 1951-2050 including historical changes in multiple environmental factors (climate, CO₂, O₃, nitrogen deposition, land use/management) and three future climate scenarios. We first investigated the historical variations of the crop productivity/yield induced by the long-term climate variability/change combined with other factors during 1951-2000. Then we further analyzed the response of food productivity to future climate change and the impacts of agriculture ecosystem on climate warming in terms of global warming potential (GWP) of three major GHGs (CO₂, CH₄ and N₂O) by 2050. 

Results/Conclusions

The preliminary results indicate that the total crop productivity in the US doubled during the past half century, which was contributed largely by nitrogen fertilizer application and increasing atmospheric CO₂. Climate change combined with ozone pollution and land conversion resulted in a large decrease in crop productivity. Under future climate scenarios (A1 and A1B) with other environmental factors unchanged, the projected crop productivity in the US will change slightly while GWP in agriculture ecosystem will reduce with different decrease rates under both scenarios with the unchanged agronomic practices. To ensure food security and minimize the associated environmental consequences, it is critical to optimize land management practices or adaptation strategies (e.g. nitrogen fertilizer and irrigation) by taking account of other environmental factors.