There have always been tensions between theory and practice in Translation Studies. Corpus-based Translation Studies (CTS) have emerged with the promise of offering a method for firmly articulating theory to practice. However, from the outset, CTS have also revived the theoretical ambition of uncovering laws and universals. Overall, the use of statistics in CTS thus seems to have partly diverted it from its empirical grounding and from the promise of articulating theory and practice. Against this trend, we present the results of a study conducted within Critical Corpus-based Translation Studies (CCTS) in which we return to one of the initial promises of Corpus-based Translation Studies and highlight problems tied to a given situation and context of translation. We have used the R software to perform exploratory statistical analyses of the Summaries of IPCC reports and their translations into French and Spanish over the period from 1990 to 2014. Our results show that an exploratory and critical corpus-based framework sheds light on the empirical work of institutional translators, notably through the analysis of terminological and phrasing choices.