## 3 Results
### Weather Anomalies
The sea level in the southern Baltic is  
Figure 6: Temperature anomalies on the seacoast [115]. constantly rising due to global warming and western zonal circulation prevailing in the region [123; 124]. The rate of increase in sea level is varied across the coast, and a higher growth rate is observed in the eastern part of the coast. For example, in Swinoujscie, the sea level increased by 14.1 cm within the past 73 years [125]. The usual daily sea levels varied between 511-520 cm (25.48% of the total variations) and 501-510 cm (22.47% of the total variations) [126]. The observable changes (increasing air temperature, diminishing snow cover of shorter duration) correspond to the climate changes reported in other European countries [126; 127; 128; 129]. Scenarios developed by the Institute of Meteorology and Water Management (IMGW) show that in 2024-2030, Pomerania may see the greatest increase in mean air temperature by more than 0.4 \({}^{\circ}\)C in Swinoujscie, Szczecin, and Shubice. The changes are likely to be observed especially in winter seasons, which are expected to be warmer, with less snow. Increased fluctuations are forecast for all meteorological parameters, with higher daily, seasonal, and annual amplitudes. A phenomenon occurring in the Baltic Sea of great importance for the maritime economy is ice. Since the 1940s and 1960s, when ice on the Baltic Sea reached its record thickness and duration, the Polish coast has seen a constant decrease in the number of days with ice covering its waters [130; 131]. In 1971-1990, the average number of days with ice was 16 in Swinoujscie, where the longest ice sheet duration was observed. However, during extremely severe winters, this number would grow to even more than 60. It is worth mentioning here that in some years, the sea did not freeze at all [132; 133]. The probability of ice formation in the early 2000s varied from 32% in the southern part of the Baltic Sea, along the Polish coast, to 100% in the north and along the Finnish and Russian coasts. Based on observations from the majority of stations, a trend towards shorter ice periods has been identified, with a maximum reduction of 44 days per century. The trend corresponds to the increasing winter temperatures throughout Europe and thus point to a relationship between climate changes and the ice situation on the Baltic Sea [134]. According to forecasts by IMGW, a significant increase in the number of days with ice sheet along the Polish coast can be expected in 2011-2030 compared to the reference period of 1971-1990 [132]. Longer ice duration is expected in each emission scenario under analysis. The scale of change is clearly varied geographically, with the smallest change in Swinoujscie and the greatest in Ustka and Hel. Changes in Ustka and Gdansk amount to 30%, and in Hel they are more than 45%. Only in Swinoujscie can a slight decrease in ice sheet duration (by less than 2%) be expected compared to the reference period. The ice severity forecast for the period of 2011-2030 was carried out using the ECHAM5 global climate model, as applied in the projections developed by IMGW. This time frame corresponds to the validated simulation range provided by the model. The expected changes in ice sheet duration (Figure 5) have been developed using the ECHAM5 global model, one of the more precise atmospheric circulation models developed by the Max-Planck Institute for Meteorology in Hamburg. The model is used for the forecasting of long-term global and regional climate changes. Data simulated by the model have been used in the analysis discussed below with reference to changes in the regional barometric pressure at sea level (SLP) and regional mean air temperature from a level of 2 m above ground level (T2) and from a level of 700 hPa (T700) [132].