Are users drawing the same conclusions from different climate data portals?

Climate data portals serve as important tools for climate services providers to effectively communicate with decision-makers. With a rapid increase in the number of such portals and the datasets underlying them, critical questions arise: do users encounter similar narratives across these platforms, and does their choice of portal influence decisions on adaptation measures? This presentation conducts a comparative analysis of two prominent Canadian portals, namely Climate Data Canada and Portraits Climatiques. Both portals feature bias-adjusted CMIP6 simulations that differ in various aspects, including bias-adjustment methodology, climate of reference, ensemble composition, and emissions scenarios. The impact of these choices is explored by assessing three core variables (daily maximum temperature, daily minimum temperature, and daily precipitation) and examining five case studies from the agriculture, transport, and health sectors. Our findings reveal significant disparities between the portals in terms of climate indicator values at the end of the century, while projected changes compared to the present climate are often more similar. Moreover, we observe a strong influence of the reference dataset choice on threshold-based indicators. Despite these discrepancies, users commonly make similar final decisions when employing both platforms, as adaptation measures are not markedly sensitive to the distinctions and as other non-climate-related factors must be considered in the decision-making process. This study sheds light on differences and similarities between climate data portals, emphasizing the need for climate services organizations to transparently communicate the implications of their choices to users, in order to guide the formulation of effective adaptation strategies.