Developing high spatial resolution data on net migration is a first step to analyse the relation between climate change, population distribution and related migration. Net migration is defined as the difference between the number of immigrants and the number of emigrants. When data on in-migration and out-migration are not available, net migration is obtained by comparing population increase over a given period of time with natural increase (births minus deaths) over the same period. This map shows the natural increase for the 2010-2014 period as estimated by the European Commission's Knowledge Centre on Migration and Demography (KCMD) at a 25km resolution level, i.e. referring to areas of 25x25 km. The full dataset provides data on population natural increase for five-year time-steps between 1975 and 2015.