"Billions more people could have difficulty accessing water if the world opts for a massive expansion in growing energy crops to fight climate change, research has found.

The idea of growing crops and trees to absorb CO2 and capturing the carbon released when they are burned for energy is a central plank to most of the Intergovernmental Panel on Climate Change’s scenarios for the negative emissions approaches needed to avoid the catastrophic impacts of more than 1.5°C of global warming.

But the technology, known as bioenergy with carbon capture and storage (BECCS), could prove a cure worse than the disease, at least when it comes to water stress.

Fabian Stenzel at the Potsdam Institute for Climate Impact Research in Germany and his colleagues project that the water needed to irrigate enough energy crops to stay under the 1.5°C limit would leave 4.58 billion people experiencing high water stress by 2100 – up from 2.28 billion today. That is 300 million more people than a scenario in which BECCS isn’t used at scale and warming spirals to a devastating 3°C."