Scientists say that machines that remove CO2 from the air will be needed to keep the rise in global temperatures in check. But these devices will have major impacts on energy, water and land use. By 2050, according to this new report, food crop prices could rise more than five-fold in some parts of the world. In the wake of the Paris climate agreement signed in 2015, researchers have tried to understand what keeping the world under a 1.5C temperature threshold would mean in practice.
One of the ideas on how to achieve this is called BECCS – bioenergy with carbon capture and storage. It means growing crops that soak up CO2, then burning them for electricity while capturing and burying the carbon that’s produced. Another technology that has raised much interest is called Direct Air Capture (DAC), where machines pull CO2 directly from the atmosphere. A number of experimental installations of this idea have been successfully implemented, notably in Switzerland and Canada. DAC will need large amounts of heat to make the process work, say the authors. This would require energy equal to 115% of current global natural gas consumption.
According to the report, with widespread use of DAC, many parts of the world will see substantial price increases in maize, wheat and rice. The worst affected areas would be in sub-Saharan Africa which could see prices rise by 5-600% by 2050. But some people involved in DAC reject the report’s findings, saying that the authors wrongly assumed that all air capture systems are the same. “We would like to point out that the paper only analysed liquid sorbent direct air capture technology whilst Climeworks has developed a solid sorbent technology that does not rely on the burning of natural gas or has a need for fresh water to deliver carbon dioxide removal from the air,” said Christoph Beuttler from Climeworks.