Global needs for nitrogen fertilizer to improve wheat yield under climate change.

Increasing global food demand will require more food production without further exceeding the planetary boundaries while simultaneously adapting to climate change. We used an ensemble of wheat simulation models with improved sink and source traits from the highest-yielding wheat genotypes to quantify potential yield gains and associated nitrogen requirements. This was explored for current and climate change scenarios across representative sites of major world wheat producing regions. The improved sink and source traits increased yield by 16% with current nitrogen fertilizer applications under both current climate and mid-century climate change scenarios. To achieve the full yield potential-a 52% increase in global average yield under a mid-century high warming climate scenario (RCP8.5), fertilizer use would need to increase fourfold over current use, which would unavoidably lead to higher environmental impacts from wheat production. Our results show the need to improve soil nitrogen availability and nitrogen use efficiency, along with yield potential.