The influence of a changing Arctic on midlatitude climate and extremes: a review of pathways and uncertainties

In the context of global warming, the ongoing reduction in Arctic sea ice and associated influences have become a focal point. Many studies have linked Arctic changes to extreme weather and climate events in the Northern Hemisphere midlatitudes, including cold spells, heatwaves, droughts, storms, and wildfires. However, the causality and physical pathways of the Arctic–midlatitude linkage remain controversial and highly uncertain, hindering the attribution of extremes to Arctic climate change. This study builds on extensive previous research and reviews recent progress in understanding the influence of Arctic amplification and sea ice loss on midlatitude climate variability, as well as the associated uncertainties. The impacts of Arctic changes on the midlatitude weather and climate are substantially mediated by the jet streams, Rossby waves, transient eddy-mean flow interactions, and the stratospheric polar vortex. Despite the enhanced comprehension of mechanisms and pathways, the aforementioned Arctic-midlatitude linkage remains debated. The ongoing prospection is attributed to the noise arising from intrinsic atmospheric variability, Arctic nonlinearities, lower latitude factors, and climate background state. The present study has sought to elucidate the intricacies of the Arctic-midlatitude linkage, with a particular focus on the ramifications for mean and extreme weather and climate conditions in Eurasia and North America. This study also specifically introduces discussions about the sources of uncertainty and possible underlying causes that need to be addressed.