Frey & Smith 2003: Polar Research 22(2), 287-300 The sensitivity of Arctic climate is documented in the instrumental record of recent decades and is evident in the large temperature increases seen over Northern Hemisphere land areas from about 40° N to 70° N (Nicholls et al. 1996). In particular, sharp temperature increases from 1966–1995 are found in Eurasia and northwest North America, with p...

A global atmosphere–ocean– sea ice general circulation model (GCM) is used in simulations of climate with greenhouse gas concentrations and sulfate aerosols prescribed from observational data (1870 through 1995) and future projections (1995 through 2100). Simulations that include the variability in solar flux from 1870 through 1995 are also performed. The variation in solar flux of +/–2 W m pro...

Existing studies of the recent warming hiatus over land are primarily based on the average of daily minimum and maximum temperatures (T2). This study compared regional warming rates of mean temperature based on T2 and T24 calculated from hourly observations available from 1998 to 2013. Both T2 and T24 show that the warming hiatus over land is apparent in the mid-latitudes of North America and E...

The recent accelerated Arctic sea ice decline has been proposed as a possible forcing factor for midlatitude circulation changes, which can be projected onto the Arctic Oscillation (AO) and/or North Atlantic Oscillation (NAO)mode.However, the timing and physicalmechanisms linkingAO responses to theArctic sea ice forcing are not entirely understood. In this study, the authors suggest a connectio...

In their contribution to PNAS, Liu et al. (1) suggested that the recent decline of Arctic sea ice has played a critical role in recent cold and snowy winters in the Northern Hemisphere (NH). This study is very interesting, but we believe it deserves several clarifications. First, in 2010, Wu et al. (2) discovered the importance of autumn Arctic sea ice in triggering regional cold extremes; for ...