Freak storms, heat waves, heavy rain-on-snow events, sea ice disintegration, permafrost thaw, coastal landslides and widespread surface melt over Greenland. These are just a few examples of “extreme events” affecting the Arctic. The Arctic has experienced dramatic changes over recent decades, including warming of more than twice the global average and a 50% decline in summer sea ice cover. Scientists and the media are increasingly focusing their attention on associated observations of new, and often highly surprising, extreme events in the region.

Local communities and ecosystems are often affected more by these extremes compared to gradual changes in the background climate conditions, opening up new and urgent avenues of research. These extremes are also increasingly being covered by the media, likely due to their more obvious impacts and their potential to capture the public’s attention, however the descriptions of the severity, rarity and links to global climate change can be hugely misrepresented, with scientists struggling to match the pace of the fast-moving news cycle and provide the often necessary context.

To explore the current state of knowledge regarding the detection, characterization and prediction of extreme Arctic events, we invited 15 scientists to a focus group discussion during the POLAR 2018 meeting in Davos, Switzerland. The diverse group of scientists represented a wide range of Arctic science disciplines, including glaciology, oceanography, atmospheric science, marine biology, land cover, and human systems. We explored the definition of extreme events and how relevant and consistent they are across Arctic sub-disciplines, the interconnectedness of different Arctic extremes, and the challenges of confidently attributing cause and effect.

We framed our discussion around two recent examples of extreme Arctic events: (1) the record high temperatures and sea ice breakup observed north of Greenland in February 2018, and (2) a tsunami triggered by a coastal landslide which devastated a local village in west Greenland in June 2017. Both of these events highlighted not only the challenges discussed above but also the contrasting spatial scales involved and impacts on local communities.

Our discussions highlighted several limitations in such efforts to better understand Arctic extremes:
• For one, the unique and rapidly changing Arctic environment can make the attribution of extremes challenging, as this requires more advanced statistical techniques to assess how rare or extreme and event might be in the context of a fast-changing mean state.
• Also, there is a clear shortage of operational weather stations deployed in the Arctic compared to lower latitudes, which makes it difficult to analyze how genuinely extreme (or rare) an event may be in a climatic (several decades) context.
• Efforts are underway to improve the Arctic observing network, but more also needs to be done to make the current datasets more easily accessible to scientists and other interested parties, along with better integration of local knowledge into media and scientific discussions.

Extreme events require and indeed provide a useful framework to bring together scientists across disciplines. We hope our group discussion summary (to be released soon) and related activities will motivate further efforts to increase our understanding of extreme events in the Arctic.

Further information: Alek Petty, Thomas Armitage, Manisha Ganeshan