Analyses of a mid-Holocene climate model ensemble and paleo-proxies reveal that the mid-Holocene Northern Hemisphere was warm.

Pronounced changes in the Arctic environment add a new potential driver of anomalous weather patterns in midlatitudes that affect billions of people. Recent studies of these Arctic/midlatitude weather linkages, however, state inconsistent conclusions. A source of uncertainty arises from the chaotic nature of the atmosphere. Thermodynamic forcing by a rapidly warming Arctic contributes to weather events through changing surface heat fluxes and large-scale temperature and pressure gradients. But internal shifts in atmospheric dynamics—the variability of the location, strength, and character of the jet stream, blocking, and stratospheric polar vortex (SPV)—obscure the direct causes and effects. It is important to understand these associated processes to differentiate Arctic-forced variability from natural variability. For example in early winter, reduced Barents/Kara Seas sea-ice coverage may reinforce existing atmospheric teleconnections between the North Atlantic/Arctic and central Asia, and affect downstream weather in East Asia. Reduced sea ice in the Chukchi Sea can amplify atmospheric ridging of high pressure near Alaska, influencing downstream weather across North America. In late winter southward displacement of the SPV, coupled to the troposphere, leads to weather extremes in Eurasia and North America. Combined tropical and sea ice conditions can modulate the variability of the SPV. Observational evidence for Arctic/midlatitude weather linkages continues to accumulate, along with understanding of connections with pre-existing climate states. Relative to natural atmospheric variability, sea-ice loss alone has played a secondary role in Arctic/midlatitude weather linkages; the full influence of Arctic amplification remains uncertain.

Reconstruction of the long‐term surface temperature history in Antarctica is important for a better understanding of human‐induced climate changes, especially since the Industrial Revolution. We present here a surface temperature history spanning the last century at Styx Glacier, located on the eastern coast of northern Victoria Land, which is reconstructed using borehole logging data. Our results indicate that surface temperatures in the 20th century were 1.7 ± 0.4 °C higher than the long term averages over 1600–1900 Common Era, indicating regional warming over the eastern coast of northern Victoria Land. However, we found no evidence for significant warming across the northern Victoria Land since the mid‐20th century. A global reanalysis as well as the reconstruction of proxy records demonstrate that the climate in this region was more affected by changes in the Southern Hemisphere Annular Mode than in the Amundsen‐Bellingshausen Sea Low.