In the past years there has been an increasing number of quantitative studies on climate-related migration. However, to date, there is no scientific consensus how and under what conditions climate variability and shocks influence population movements. To this end, this study aims to empirically assess the relationship using a meta-analysis approach which allows us not only to derive a qualitative understanding, but also to quantify the effects and study heterogeneities across study lines. For reasons of comparability, we focus on 25 macro-level studies using country-level data which were identified in a systematic literature search. Employing a standardization approach, we are able to harmonize migration estimates across studies. Besides average effects, we investigate the differences in effect sizes between studies considering in particular the role of contextual factors and different climatic influences. Our preliminary findings suggest that these strongly influence the strength and direction of the climate effects on migration.