PNAS Nexus (2026). https://doi.org/10.1093/pnasnexus/pgag123"> Choropleth bivariate maps of negative-emission potential and ecological trade-offs from expanding biofuel crops in historically cultivated areas. Credit: PNAS Nexus (2026). https://doi.org/10.1093/pnasnexus/pgag123 A technology designed to mitigate global warming could, paradoxically, contribute to carbon emissions if hotter temperatures lead to a shift in where bioenergy crops are grown. Bioenergy with carbon capture and storage (BECCS) involves combusting or fermenting biological materials to produce energy while capturing the carbon dioxide emitted by the process and storing it underground. BECCS could help mitigate climate change, and many models of a net-zero emissions future assume widespread use of the technology. However, first generation bioenergy production requires substantial land area to grow the crops used as feedstocks.…