The premise that global warming changes the conditions for crop production was investigated throughout Switzerland on the basis of a climate suitability for grain maize cultivation. Gridded projections1 of temperature changes for three time periods (2020–49, 2045–74, 2070–99) available from twenty climate-model chains for the A2 emissions scenario (i.e. the «business as usual» scenario) were used. It was found that with climate warming, the suitable production area increases at higher altitudes but decreases at lower altitudes in the longer term. In a second part of the study, we investigated the influence of individual climatic factors on climate suitability using combined temperature and precipitation scenarios from ten model chains for the Zurich-Reckenholz and Changins sites. Results suggest that heat stress and accelerated plant development are increasingly limiting climate suitability at both sites, whilst water shortage during maturation is only increasing significantly at the Changins site in western Switzerland. The shortening of growth phases also plays a role here, since the temporal shift in crop development can reduce the risk of drought stress if droughtsensitive phenological periods are shifted away from periods of most intense stress. Despite uncertainties with regard to long-term climate change, the results of this study can provide advice for the planning of possible climate change adaptation measures (i.e. future cultivar choice, shifts in production areas).
The impact of climate change on maize cultivation in Switzerland