"If we look at how much more water we will need for food and how much more for biomass for energy going forward ... it is quite worrying," said Jan Lundqvist, who heads the scientific programme at the Stockholm International Water Institute (SIWI).
Global food needs are expected to roughly double by 2050, at the same time as climate change and dwindling oil reserves are pressuring countries to set aside ever more land for producing biomass to replace greenhouse gas-emitting fossil fuels.
These parallel global trends risk colliding with "the water-constrained biophysical reality of the planet," according to SIWI, which hosted the the World Water Week in the Swedish capital last week.
"Almost every increase in water used in agriculture will affect water availability for other uses, including that needed to keep ecosystems healthy and resilient in the f