Data and Methods of Investigation

The study covers the entire area of Poland. Part II of the book presents the results of the study of climate change before instrumental measurements in Poland in the last millennium. More than 50 proxy series including documentary evidences, dendrochronological records and varved sediment records were analysed. On this basis, reconstructions of: summer and winter air temperature, winter severity, precipitation (liquid and solid) and droughts were performed. Part III analysed the long-term changes and variability of 36 climate characteristics for 14 climate elements, indices, meteorological phenomena and weather types using data from 79 weather stations. Most of the climate elements studied were analysed for the base period 1951–2018 (68 years). For some elements and indices shorter study periods were considered. In addition, climate variability was analysed for 10 long measuring series up to 239 years. Variability of circulation indices over a period of 147 years (1873–2019) was investigated as well. Uniform research methods common to all elements and indices were used: (1) coefficient of variability (%), (2) absolute trend (unit/10y); (3) relative trend (%/10y). Part IV of the book deals with projected changes in temperature, precipitation and thermal indices related to the agriculture and energy sectors. In this study, 8 regional climate models from the EURO-CORDEX experiment were used for 2 representative concentration pathways: (1) corresponding to radiative forcing value +4.5 W.m−2 in 2100 (RCP4.5) and (2) corresponding to radiative forcing value +8.5 W.m−2 in 2100 (RCP8.5) relative to pre-industrial values. Two future time horizons were carried out for each concentration pathway: (1) near future: 2021–2050 and (2) far future: 2071–2100 with reference to the period of 1971–2000. Future projections were created for: 8 characteristics of temperature, 10 characteristics of precipitation, 5 characteristics for agriculture indices and 4 for energy demands indices.