The quantification of climate change impacts on several human activities depends on reliable weather data series, without gaps and long enough to build up future climate. Based on that, this study aimed to evaluate the performance of temperature-based models for estimating global solar radiation and gridded databases (AgCFSR, AgMERRA, NASA/POWER, and XAVIER) as alternative ways for filling gaps in historical weather series (1980–2009) in Brazil and to project climate change scenarios based on measured and gridded weather data. Projections for mid- and end-of-century periods (2040–2069 and 2070–2099), using seven global climate models from CMIP5 under intermediate (RCP4.5) and high (RCP8.5) emission scenarios, were performed. The Bristow–Campbell model was the one that best estimated solar radiation, whereas the XAVIER gridded database was the closest to observed weather data. Future climate projections, under RCP4.5 and RCP8.5 scenarios, as expected, showed warmer conditions for all scenarios over Brazil. On the contrary, rainfall projections are more uncertain. Despite that, the rainfall amounts will be reduced in the North-Northeast region and increased in Southern Brazil. No significant differences between projections using the observed and XAVIER gridded database were observed; therefore, such a database showed to be reliable for both to fill gaps and to generate climate change scenarios.

Climate models indicate that increasing atmospheric concentrations of greenhouse gases (GHG), mainly CO₂, will alter climate by increasing temperatures and changing rainfall patterns. Considering that potato crop stands out as the most important non-grain crop in the world, it is imperative to understand how climate change will impact this crop and how it will affect global food security. In this sense, crop simulation models are useful tools to estimate crop growth, development and yield in response to climatic conditions, soils, genotype and crop management. Among the several potato crop simulation models, DSSAT-SUBSTOR-Potato is the main one and widely used around the world. The aim of this study was to validate this model for Brazilian conditions and used it to simulate the impacts of projected climate change on potato crop in the main Brazilian producing regions, for different growing seasons, considering an ensemble of different general circulation models, projected for 2040–2069 and 2070–2099 periods, under two GHG Representative Concentration Pathways (RCP4.5 and RCP8.5). The results showed that Brazil will have warmer climate with wetter conditions in the south and less rainfall in the north, which will impact potato crop in different ways, depending on the producing region and growing season. In Southern Brazil, future climate will benefit potato yield, mainly during the 3rd growing season. On the other hand, locations with warmer and drier climates will have lower potato yields in relation to the present, mostly during the 1st growing season, when extremely high temperatures and water deficit will limit plants’ growth. These impacts will be less expressive in the most optimist scenario (RCP4.5), while more intense yield losses are expected under the RCP8.5 in the end of the century.