Abstract:The recognition of changes in the course of agricultural thermal periods is vital when it comes to determining appropriate measures for adapting agriculture to climate change. The present study examined changes in air temperature between 1951 and 2014 in the area of south-western Poland. A statistically significant, positive linear trend was confirmed for the annual average temperature, seasonal averages, and monthly averages in the periods spanning February-May and July-August. From the beginning of the 21st century, the period of winter dormancy of plants started increasingly later; farming and plant vegetation periods started increasingly earlier, and the period of active plant growth was prolonged. Among the considered agricultural periods, the growing season was the most prolonged. The duration of the farming period was also significantly longer, but the winter dormancy period was shortened. The negative linear trend of days when the temperature stood at <0 • C was statistically confirmed for temperature in the entire region and most of the stations. In terms of predicting the consequences of the changes that were observed today over the next decades, this is not an easy task. However, the nature of these changes suggests that further cultivation of winter crops may require far-reaching adaptation measures.

Our aim was to determine relationships between the tropospheric ozone concentration and the nitrogen dioxide concentration, selected meteorological factors and radiation-effective temperature in the suburban area of the city of Wroclaw. Hourly data from 2006-2011 used in the study included concentrations of tropospheric ozone, nitrogen dioxide concentrations, air temperature, air humidity, wind velocity and total irradiance of the sun. Radiation-effective temperature (TRE) was determined on the basis of the four meteorological elements. Concentrations of ozone in southwest Poland show annual, seasonal and daily variation. The highest values occur in the warmest time of the year and day, while the lowest ones are noted in the cold season of the year, in October and in the morning. The variation of ozone concentrations was found to be shaped by changes in nitrogen dioxide concentrations, meteorological elements and the bioclimatic indicator. Ozone and nitrogen dioxide were mutually most strongly correlated in the winter season. In the warm season of the year, from April to October, the ozone concentration was mainly shaped by air temperature, solar radiation, wind velocity and TRE (positive effects), and by relative humidity of the air (a negative influence). The multiple regression equation best described the ozone concentration variation in May. Increased concentrations of ozone were found to appear during thermal stress, expressed as a sensation of warmth/heat, but could also occur under thermal comfort conditions.

Poland, like other countries in the world, increasingly experiences the ongoing climate change. However, the level of preparation of the country and its society for climate change in the second decade of the 21st century can be evaluated as low. The Municipal Adaptation Plans (MAPs) created in 2017–2019 became a subject of research studies whose main goal was to determine the typology of adaptation actions to be undertaken as part of MAPs in the 14 selected Polish cities in various geographical regions. Moreover, the type and scope of intended actions were analysed according to the planned amount of expenditure and from the perspective of sectors. The tasks accepted for implementation up to 2030 mainly relate to modernisation and development of transport systems and to actions connected with physical infrastructure. A large number of tasks and even a bigger scale of financial sources planned in the analysed MAPs for mitigation actions show that Polish cities are at an initial stage of actions for climate protection. The typology of adaptation actions which the work proposes may be helpful in research carried out in countries of a similar level of preparation for adaptation to climate change.

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The onion is the most common vegetable cultivated in Poland and yield is marked by high year to year variability. The yield quantity is predominantly affected by variable meteorological conditions, especially by precipitation deficiency. Data were collected from the Research Centre for Cultivar Testing and the Institute of Meteorology and Water Management for the period 1966-2005 to evaluate the effect of precipitation conditions on the yield of onions (Allium cepa L.) cultivated in Poland using multiple regression analysis. Verification of the curvilinear regression equation was conducted on the basis of relative forecast error and average relative forecast error. For this equation the ARFE amounted to 9.6%. The threshold precipitation value, i.e. the value at which reduction by at least 5% of the total yield occurs, was determined by curvilinear regression. Reduction of potential yield caused by precipitation deficiency and the frequency of precipitation deficiency were determined. Reductions of at least 5% in the average domestic onion yield in Poland occurred when atmospheric precipitation was ? 183 mm. This level of precipitation constituted 87% of the norm and took place in the period between the end of emergence to the beginning of leaf bending. Potential reduction in onion yield in Poland caused by precipitation deficiency in this period varied between 9 and 18%. In Poland, the frequency of atmospheric precipitation deficiency between 1966 to 2005 varied from 10% in the south-east to 50% in the central west and north west. The average frequency of atmospheric precipitation deficiency amounted to about 37%.