One of the most striking features of global climate change is the strongly amplified response of surface air temperature in the Arctic and the associated strong decline in sea ice. Both observational and climate modeling studies have shown that the Arctic is a region very susceptible to climate change; moreover, changes occurring in the Arctic are likely to have more wide-spread implications. Arctic amplification manifests itself in a number of ways, most notably in the current retreat and thinning of Arctic sea ice. A variety of processes and feedbacks have been proposed that contribute to amplified Arctic warming, most of them associated with sea ice. The most well-known is the surface-albedo feedback, which is associated with retreating sea-ice and snow cover. While most climate models exhibit an Arctic amplification signal with respect to ongoing and future changes, the inter-model range in simulated amplification is large, suggesting that the magnitudes of the various feedbacks contributing to Arctic warming and the role of sea ice therein are still uncertain. This session specifically aims to identify, characterise and quantify the processes and feedbacks that govern amplified Arctic warming and sea ice retreat, Arctic climate variability, and it also addresses the climate impacts on the lower latitudes associated with Arctic changes (for instance the relation between sea ice retreat, heat flux changes and atmospheric circulation changes beyond the Arctic region). We therefore invite contributions on the causes, mechanisms and climate feedbacks associated with Arctic climate change and sea ice retreat, climate variability, and the possible links to weather and climate outside the Arctic. We welcome studies based both on climate model results and/or observational datasets, for near-past, present and future climate changes.