Deficiencies of micronutrients, including essential trace elements, affect up to 3 billion people worldwide. The dietary availability of trace elements is determined largely by their soil concentrations. Until now, the mechanisms governing soil concentrations have been evaluated in small-scale studies, which identify soil physicochemical properties as governing variables. However, global concentrations of trace elements and the factors controlling their distributions are virtually unknown. We used 33,241 soil data points to model recent (1980–1999) global distributions of Selenium (Se), an essential trace element that is required for humans. Worldwide, up to one in seven people have been estimated to have low dietary Se intake. Contrary to small-scale studies, soil Se concentrations were dominated by climate–soil interactions. Using moderate climate-change scenarios for 2080–2099, we predicted that changes in climate and soil organic carbon content will lead to overall decreased soil Se concentrations, particularly in agricultural areas; these decreases could increase the prevalence of Se deficiency. The importance of climate–soil interactions to Se distributions suggests that other trace elements with similar retention mechanisms will be similarly affected by climate change.
Bibliographical noteThis work was supported by Swiss National Science Foundation Grants PP00P2_133619 and PP00P2_163747 and Eawag, the Swiss Federal Institute of Aquatic Science and Technology. P.S. is supported by the Delivering Food Security on Limited Land (DEVIL) project (UK Natural Environmental Research Council NE/M021327/1) funded by the Belmont Forum/Joint Programming Initiative on Agriculture, Food Security and Climate Change (FACCE-JPI) and by UK Biotechnology and Biological Sciences Research Council Project BB/L000113/1. Rothamsted Research is grant-aided by the UK Biotechnology and Biological Sciences Research Council.
- global distribution
- climate change