Are continuing changes in the Arctic influencing wind patterns and the occurrence of extreme weather events in northern mid-latitudes? The chaotic nature of atmospheric circulation precludes easy answers. The topic is a major science challenge, as continued Arctic temperature increases are an inevitable aspect of anthropogenic climate change. We propose a perspective that rejects simple cause-and-effect pathways and notes diagnostic challenges in interpreting atmospheric dynamics. We present a way forward based on understanding multiple processes that lead to uncertainties in Arctic and mid-latitude weather and climate linkages. We emphasize community coordination for both scientific progress and communication to a broader public.

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Arctic warming is unequivocal, substantial and ongoing

Changes in Arctic climate in the last three decades are substantial. Since 1980, Arctic temperature increases have exceeded those of the Northern Hemisphere average by at least a factor of two. Over land north of 60° N, 12 of the past 15 years have exhibited the largest annual mean surface air temperature anomalies since 1900. AA is also manifested in the loss of sea ice, glaciers, snow and permafrost, a longer open-water season, and shifts in Arctic ecosystems. Sea ice has undergone an unprecedented decline over the past three decades with a two-thirds reduction in volume. Comparable decreases in snow cover have occurred during May and June. AA is strongest in autumn/winter with largest values over regions of sea ice loss, while the areas of greatest warming in summer are located over high-latitude land where rates of spring snow loss have exceeded even those of sea-ice loss.

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Source: James E. Overland, Klaus Dethloff, Jennifer A. Francis, Richard J. Hall, Edward Hanna, Seong-Joong Kim, James A. Screen, Theodore G. Shepherd & Timo Vihma, Nature.com (Climate Change)

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