## 4 Discussion  
The surface temperature warming observed in the Antarctic Peninsula region in the last few decades [2; 3] resulted in a reduced seasonal snow cover [40], an increased ablation of glacier ice located below the glacier's ELA [30], an increased snowfall which could increase the future ice discharge from feeding areas [41], and it may have caused an increased rate of sublimation and evaporation, further contributing to the removal of \(\sim\)9% of precipitation in the Antarctic Peninsula region [42]. The summer temperatures on King George Island are above zero between December and February, and close to melting temperatures in spring and autumn, so, even a small degree of warming may have a significant impact on glaciers. [PERSON] [14] calculated that, for the Ecology Glacier, an increase of the air temperature by 1 \({}^{\circ}\)C would intensify ablation by 15%. As a consequence of warmer temperatures, the melting season is longer and the accumulation of seasonal snow cover is reduced. Moreover,the temperature gradient between a glacier and its forefield is higher when snow cover is absent. The gradient can cause a positive feedback, which may, in addition, increase the surface melting at the front margin of a glacier. Since the number of days with snow cover decreases due to higher temperatures and smaller precipitation, it may also negatively affect the ice balance at the glacier front zone. Therefore, the temperature warming in spring and autumn is particularly important as it extends the ablation season, further diminishing the balance of glaciers. In the winter, melting occurs only during mid-winter thawing events [43; 44]. These events are caused by dynamic weather systems bringing warmer air masses to the South Shetland region. The alteration of this circulation pattern may play an important role in increasing the frequency and severity of mid-winter thawing events. The air temperature and precipitation trends for the period of 1968-2011 from Bellingshausen Station do not explain why the fastest ratios of glacier area loss occurred between 1989-2001. Between 1968-2007, the air temperature was increasing (at \(+0.2\)\({}^{\circ}\)C/10 year) and the precipitation was decreasing (at \(-2.38\) mm/year). Our results suggest that the rate of reduction in glaciated areas was the fastest between 1989-2001, compared with the 1979-1989 and 2001-2007 periods being twice as slow. Similar trends could be observed in annual PDD sums. The averages of PDD for the investigated periods from the Bellingshausen, Jubany, and Ferraz stations (Figure 2) indicate higher PDD values for the 1989-2001 period compared to 2001-2007. Additionally, the 1979-1989 averages from Bellingshausen Station are lower than the 1989-2001 average. The warmer period between 1989-2001 also stands out as the only period that had a faster ratio of glaciated area loss for land-terminating glaciers than tidewater glaciers (Figure 6), which suggests the presence of an elongated melt season during that period. This could explain the changes observed in the retreat ratios of land-terminating glaciers with ablation dominated by surface melting, as they would most quickly respond to the climate change between 1989-2001. [PERSON] et al. [8] showed very slow glacier flow velocities for the Bellingshausen Dome and [PERSON] et al. [45] showed that the velocities on the Arctowski Icefield since 1997 were similar. Similarly, a study by [PERSON] et al. [46] demonstrated slow surface velocities and a thickness in the lower elevations of the Warszawa Icefield system. Slow surface velocities and increasing PDD results in changes in the glaciers' Equilibrium-Line Altitude (ELA). Between 1967 and 1999, the ELA on King George Island rose from approximately 140 m a.s.l. [27] to 220 m a.s.l. (Table 2). In 2006, the highest level of ELA was observed (290 m a.s.l. ), but it is worth notice that 2006 is the warmest year in the period 2001-2007 (Figure 2) and the ELA of the early 2000s may have been lower.