Future Rime Ice Conditions for Energy Infrastructure over Fennoscandia Resolved with a High-Resolution Regional Climate Model

Abstract. Societies today are increasingly reliant on electricity, underscoring the need for reliable energy production. In cold climate regions, ice accumulation can cause significant harm to structures such as power transmission lines, leading to power loss or, in the worst case, the collapse of wires or transmission towers. Thus, since climate change is expected to impact winter weather conditions in northern Europe, its effects on atmospheric icing occurrence over the Fennoscandian region is a crucial area of study. Here we utilize an ice accretion model based on ISO 12494, driven by outputs from the high-resolution regional climate model HCLIM, to analyze in-cloud icing conditions over two twenty-year periods: mid-century (2040–2060) and end-of-century (2080–2100). The regional outputs are bounded by two global climate models (EC-EARTH and GFDLCM3, respectively) under the highly warming RCP 8.5 emission scenario. The results suggest a general decrease in in-cloud icing conditions over northern Europe compared to the historical period (1985–2005). An exception lies in the northern parts of Fennoscandia and locally over higher altitudes, where some increasing trend is seen, particularly for annual maxima. Under the RCP 8.5 scenario, freezing temperatures become less common; however, rising temperatures allow for more moisture, potentially enhancing in-cloud icing if enough freezing temperatures remain.