The effects of climate change in the Arctic are affecting not only sea ice but, increasingly, visibility as well. A recent study by the Russian Arctic and Antarctic Research Institute (AARI) shows that the frequency of dangerously reduced visibility along the coast of the Kara Sea has increased significantly since the 1990s. This poses a growing challenge for shipping on the Northeast Passage.
The Kara Sea forms the western entrance to the Northeast Passage, one of the most important Arctic shipping routes between Europe and Asia. Today, large Arc7-class tankers with a length of up to 300 metres operate there. If visibility falls below 200 metres, it becomes considerably more difficult to manoeuvre these ships safely. When visibility is less than 50 metres, meteorologists refer to this as a hazardous weather event.
For their study, the scientists analysed weather data from the coastal stations at Dikson and Cape Chelyuskin covering the years 1966 to 2021. This enabled them to compare the climatically cooler period from 1960 to 1991 with the current phase of rapid Arctic warming.
The analysis reveals two annual peaks in reduced visibility: in winter, these are mainly caused by snowstorms, whilst in summer fog predominates. The latter occurs more frequently because melting sea ice exposes larger areas of water, thereby releasing more moisture into the atmosphere. At the Cape Chelyuskin weather station in particular, summer fog is now more common than winter snowstorms – a clear indication of changing climatic conditions.
According to the researchers, reduced visibility is a factor of climate change in the Arctic that has been underestimated until now. Whilst the decline in the extent and thickness of sea ice is being studied intensively, increasing fog formation is only now coming more into focus. For shipping, this means that modern hydrometeorological forecasts and precise voyage planning will become even more important in future to ensure safety on the Northeast Passage.
Heiner Kubny, PolarJournal