Climate change decreases suitable areas for rapeseed cultivation in Europe but provides new opportunities for white mustard as an alternative oilseed for biofuel production

Abstract

Oilseed crops, including several mustards, are cultivated as biofuel sources worldwide. However, common mustard crops (e.g., the rapeseed Brassica napus) grow naturally in mesic temperate regions, which are expected to be impaired by global warming and increased aridity. In particular, increased aridity is predicted to reduce the oil concentration and seed yield of rapeseed crops. There is therefore an urgent need to identify alternative bioenergy crops that are preadapted to future climatic conditions. An alternative to conventional Brassica species for biodiesel production is the white mustard Sinapis alba, which is native to the circum-Mediterranean region and has a high seed lipid content. S. alba grows spontaneously in olive groves and other widespread Mediterranean crops; accordingly, it could be easily cultivated by companion planting to improve ecosystem function by decreasing soil loss, controlling microbial disease, and assisting in the maintenance of biodiversity. In this study, using species distribution modeling, we predicted climatically suitable areas for the cultivation of S. alba in Western Europe across the Mediterranean Basin under present climatic conditions and several climate change scenarios. We show that current climatically suitable areas for S. alba cultivation do not overlap with those for B. napus. Unlike B. napus, S. alba could be cultivated throughout most of the circum-Mediterranean region. According to our models, increases in aridity and annual mean temperatures will expand the climatically suitable areas for S. alba in the Mediterranean Basin. However, suitable areas for the cultivation of B. napus will decrease significantly in Western Europe. Our results indicate that S. alba is a strong, environmentally safe candidate for biofuel production throughout the Mediterranean Basin and other Western European countries, especially under climate change scenarios that are expected to impair current oilseed crops.