Projections of global rice yields account for climate change. They do not, however, considerthe coupled stresses of impending climate change and arsenic in paddy soils. Here, we showin a greenhouse study that future conditions cause a greater proportion of pore-waterarsenite, the more toxic form of arsenic, in the rhizosphere of CalifornianOryza sativaL.variety M206, grown on Californian paddy soil. As a result, grain yields decrease by 39% compared to yields at today’s arsenic soil concentrations. In addition, future climatic con-ditions cause a nearly twofold increase of grain inorganic arsenic concentrations. Ourfindingsindicate that climate-induced changes in soil arsenic behaviour and plant response will lead tocurrently unforeseen losses in rice grain productivity and quality. Pursuing rice varieties andcrop management practices that alleviate the coupled stresses of soil arsenic and change inclimatic factors are needed to overcome the currently impending food crisis.