The health of the Baltic Sea is under heavy human-induced pressures exacerbated by climate change. This study explores the use of interactive sonification for functionally raising awareness and communicating negative emotions about vessel emissions in the Baltic Sea and how it can contribute to making sense of that data. A prototype of an interactive Baltic Sea map incorporating interactive sonification of vessel data was created. The prototype was evaluated in exploratory prototype sessions followed by semi-structured interviews with 10 participants divided into two groups, one receiving both visual and sonic feedback and the other receiving only visual feedback. The two groups used the prototype to identify vessels’ data and shape their perception of the vessels’ emissions. Observed differences between the two groups in stated emotions, use of metaphoric language, and identification of positive and negative vessels on the map indicate that the interactive sonification elicited emotional reactions as part of a sense-making process.