Cross-CI Assessment of Risks and Cascading Effects in ATLANTIS Project

Critical Infrastructures (CIs) are the backbone of modern societies, providing essential services whose disruption can have severe consequences. The interdependencies among the CIs, across sectors and national borders, add significant complexity to risk and resilience management. While various EU Directives and EU-funded projects have addressed CI risk management, most efforts have focused on individual infrastructures rather than systemic cross-sector and cross-border approaches. In the EU-funded project ATLANTIS, we address this gap by advancing CI risk and resilience assessment towards a fully integrated European protection framework. We emphasise a holistic, multi-level approach that transcends individual assets, enabling coordination across operators, sectors, and national borders. To this end, we introduce a comprehensive risk assessment methodology that explicitly accounts for interdependencies among CIs and evaluates potential impacts and probabilities of disruptive events. This methodology is underpinned by the tailored data management framework, structured across three integrated layers. To validate the approach, novel tools and methods were implemented and tested in three large-scale pilot exercises, conducted through a series of stakeholder workshops. Results indicated measurable improvements in CI preparedness and awareness, ranging from approximately 5% to 55%, depending on the threat scenario and stakeholder group. The findings demonstrate that our approach delivers added value by supporting enhanced decision-making and fostering consistent, cross-CI communication through a shared platform. This paper presents the key components, cross-CI and multi-threat risk assessment methodology, and testing outcomes of the ATLANTIS project, highlighting its contribution to advancing European CI resilience.