Uncertainties in the climate indicators can be referred to the choice of emission scenarios, assumptions in global and regional climate models as well as in the hydrological model and, moreover, natural variability. The uncertainties are reflected in the spread of results in a model ensemble for a given climate indicator. The ensemble median is a robust statistic from an ensemble. However, the spread in the results also gives important information, which can be used to guide the interpretation as it informs about uncertainties involved. For example, do all or most models project the same sign of the change? Sometimes the uncertainty (spread) is large, but still all models consistently show an increase for a specific indicator. This is a robust result that points to an increase, although with uncertainty of the magnitude of the change. Sometimes there is a mix of about half of the models showing an increase, and the other half showing a decrease. The change is not robust in this case

Agreement on sign of change compared to the reference period is a measure of how robust the result is.