Design and Usage of Line Graphs in the Visualisation of Climate Change Data

Data visualisation has become a substantial part of science and of our daily life. Effective data visualisation strategies are crucial for climate change communication. Despite the large variety of visualisation tools, line graphs with time-series are still one of the forms of data presentation relied on the most. In three journal manuscripts, the experiments of the present dissertation aimed at examining the role of line graphs in climate change communication. The first manuscript tested whether emotion associations of shapes reported in the literature have to be taken into account when designing data graphs. Experiment 1 showed that the triangular symbols, frequently used as point markers in line graphs, do not affect how threatening or arousing the climate change graphs are perceived. However, they affect threat ratings when graphs are not labelled (Experiment 2). The second manuscript tested whether line graphs are consistently preferable to tables across measures such as speed, accuracy, and subjective certainty of trend identification in climate change data. Experiment 3 revealed that this was indeed the case for speed and subjective certainty variables. The third manuscript targeted a domain where line graphs are relevant in finding a way to mitigate climate change. Wind power is a renewable energy characterized by high fluctuation. The variation of wind energy input throughout the day is often communicated via line graphs. Experiment 4 showed that people can consistently judge fluctuation and predictableness of generated wind energy on different days. Importantly, making fluctuation in wind energy supply transparent did not affect the acceptance of wind energy and wind plants. Overall, the results of the experiments included in this dissertation extend our knowledge on how to use line graphs when communicating climate change issues. The results suggest that how we present the data regarding climate change might significantly affect the process-effectivity.