This paper discusses the emerging and future cyber threats to critical systems identified during the EU/FP7 project ICT-FORWARD. Threats were identified after extensive discussions with both domain experts and IT security professionals from academia, industry, and government organizations. The ultimate goal of the work was to identify the areas in which cyber threats could occur and cause serious and undesirable consequences, based on the characteristics of critical systems. A model of a critical system is suggested and used to distill a list of cyber threats specific to such systems. The impact of the identified threats is illustrated by an example scenario in order to stress the risks and consequences that the materialization of such threats could entail. Finally, we discuss possible solutions and security measures that could be developed and implemented to mitigate the situation.