An article in Nature magazine by German researchers has cast doubt on the scale at which bioenergy with carbon capture and storage could be deployed worldwide. The negative emissions technology involves burning biomass then capturing and storing the resulting CO­₂ geologically, and is seen as one means by which the world may avert the worst of climate change, but the research has found that large-scale deployment would lead to grave problems with freshwater availability along with problems regarding land use, biodiversity and fertilizer use. The researchers developed a model which excluded the use of lands currently being used for food or feed production, then examined the impacts of BECCS on five ‘planetary boundaries’ – climate change and biosphere integrity, land-system change, biogeochemical flows and freshwater use (of which all but freshwater use have already been ‘transgressed’). The model showed that less than 0.1 gigatonnes of CO₂ per year could be reduced from the atmosphere per year without pushing the planetary boundaries for biosphere integrity, land-system change, biogeochemical flows and freshwater use into a state outside of their uncertainty ranges. This amount is well below the 0.6-4.1 gigatonnes per year projected to be required by mid-century; however, the researchers acknowledge that better quantification of planetary boundaries, or use of residues rather than the woody or herbaceous biomass plantations assumed, may alter the picture to some extent.