We present a study of the development of a thermo-erosional notch at the waterline and its influence on calving of Hansbreen, a medium-sized grounded tidewater glacier in southern Svalbard. The study is based on the results of undercut notch melt modelling, based on measurements of sea-water properties, repeated terrestrial laser scans and analysis of time-lapse camera images. There is a strong correlation between observed calving activity and modelled melt rate of the undercut notch. Measured depths of the undercut reach 4 m and vary greatly over time. The calving activity of Hansbreen was significantly lower in 2011 than in 2012, due to the persistent presence of the ice pack in Hornsund fjord, which cooled the sea surface and suppressed the wave action. Calving on Hansbreen is controlled by a local imbalance of forces at the front, due to thermo-erosional undercutting at the sea waterline. Calving activity is therefore sensitive to changes in sea-water temperature and wave height. It may be expected that calving rates will rise with increased advection of warm oceanic water to the Arctic.

The mechanism of glacier recession and its climatic controls are complex processes that differ across the Arctic region. Here, we investigate factors influencing front variations of Hansbreen, a glacier terminated in Hornsund fjord (SW Svalbard). We apply remote sensing data to observe glacier front fluctuations between 1992 and 2015 and compare them to atmospheric and oceanographic data, sea water depth at the terminus and surface velocity. Rate of subglacial meltwater discharge approximated by the seasonal positive degree‐day index (PDD) together with sea thermal conditions appear to be the main factors responsible for the fluctuations of the front of Hansbreen, while water depth at the front plays a secondary role. Taking into account ocean and air thermal conditions, the studied period has been divided into warm, cold and moderate years. The glacier retreated considerably throughout a bedrock overdeepening in the very warm period 2012–2014. This recession coincided with a slower ice flow due to intense subglacial runoff and increased submarine melting. The long‐term retreat was interrupted by glacier advances in colder years, regardless of water depth at the front. The slower recession rate was the combined effect of decreased subglacial melting and increased glacier movement associated with lower subglacial runoff. Although the seasonal PDD is a good indicator of the front fluctuations, the duration of the retreat and advance periods are strongly correlated with the sea surface temperature. Expected climate warming and an increase of water temperature in the West Spitsbergen Current will stimulate further recession of Hansbreen in future.

We describe the annual pattern of frontal ablation driven by submarine melting mechanisms at the Hansbreen terminus: these are reflected in the intensity and spatial distribution of calving events. Analysis of time-lapse images of the Hansbreen front in conjunction with oceanographic and meteorological data shows that calving intensity is driven primarily by seawater temperature. Regression analysis also highlights the importance of air temperature, which we take to be a proxy for surface ablation and subglacial discharge. This, combined with seasonal changes in ice cliff tortuosity and the increasing significance of wave motion outside the ablation season, enabled us to determine seasonal changes in the mechanisms of ice cliff undercutting by submarine melting. While submarine melting controlled by estuarine circulation primarily drives frontal ablation in summer, wave-driven melting at the waterline is more important outside the ablation season. During winter, ice cliff undercutting by melting is suspended by low seawater temperature, negligible subglacial water discharge and sea-ice cover. The most intense frontal ablation, recorded in summer, was related to higher sea temperature and vigorous estuarine circulation.

This study presents the results of a 5-year monitoring program of ice cover, water temperature, and local meteorological conditions carried out in three reference lakes in the periglacial zone of the Polish Tatra Mountains. On the basis of this information, the relationships between the weighted mean water temperature of each of these lakes and the air temperature, wind speed, precipitation, and ice–snow cover in the summer, spring, and autumn seasons, as well as year-round, were described, and the roles of the morphometry of lakes and the topography of their catchments were determined. It was found that the sensitivity of the lakes to climate warming increased with a decrease in their area/depth and shade, and with an increase in altitude and the share of wind-blown snow in the formation of the ice–snow cover. An increase in the mean annual air temperature does not necessarily translate into the warming of lakes, but, paradoxically, may result in their cooling. The current climate may not be best reflected by the most sensitive lakes, but rather by the largest ones located in the subalpine zone.