This chapter aims to examine the environmental impact of EU technological strategies, ultimately challenging the idea that the Union is concretely envisaging a really sustainable form of digital sovereignty, in particular, by neglecting the consequences of digital policies beyond its borders. We start by tracing the genealogy of the digitalisation and green strategy in the EU, explaining to what extent they are currently considered as two ‘twin’ policies (II). We then focus on EU technology strategies, analysing how digital sovereignty has recently become a guiding principle in the context of a broader EU quest for strategic autonomy from third countries. Despite not being univocally defined, we illustrate how digital sovereignty strategies concretely take a ‘centripetal’ or a ‘centrifugal’ approach (III). The core contribution of our chapter then lies in the analysis of the environmental impact of EU technological policies as oriented by the EU objective of achieving a status of digital sovereignty. We will identify the generation of a rebound effect as the symptom of a ‘digital insularity’ attitude, where the EU still conceives the digital and green transitions as two siloed policies in terms of effects. We will finally introduce the concept of ‘environmental sovereignism’ to denote the adoption of a ‘Europe first’ attitude in setting twin transition strategies, which de facto neglects the impact of EU policies beyond its borders (IV). The last section will conclude presenting the theoretical alternative of starting to pursue a more digitally ‘sober’ approach (V).