Bioenergy Crops for Low Warming Targets Require Half of the Present Agricultural Fertilizer Use

Bioenergy with carbon capture and
storage (BECCS) is a key option
for removing CO2 from the atmosphere over time to achieve
climate mitigation. However, an overlooked impact of BECCS is the
amount of nutrients required to sustain the production. Here, we use
an observation-driven approach to estimate the future bioenergy biomass
production for land-use scenarios maximizing BECCS and the pertaining
nutrient requirements. The projected global biomass production during
the 21st century is comparable to the CO2 removal target
for 2 °C warming scenarios. However, 9–19% of this future
production hinges on agrotechnology improvement, which remains uncertain.
Additional nutrients from fertilizers, corresponding to 56.8 ±
6.1% of the present-day agricultural fertilizer, will be needed to
replenish the nutrients removed in harvested biomass at the end of
the century, resulting in additional costs and greenhouse gas emissions.
Our study reveals the nutrient challenges associated with BECCS and
calls for additional management efforts to grow bioenergy crops in
a sustainable way.