Heat stress is one of the environmental factors influencing the health of individuals and the wider population. There is a large body of research to document significant increases in mortality and morbidity during heat waves all over the world. This paper presents key results of research dealing with heat-related mortality (HRM) in various cities in Poland which cover about 25% of the country's population. Daily mortality and weather data reports for the years 1991-2000 were used. The intensity of heat stress was assessed by the universal thermal climate index (UTCI). The research considers also the projections of future bioclimate to the end of twenty-first century. Brain storming discussions were applied to find necessary adaptation strategies of healthcare system (HCS) in Poland, to minimise negative effects of heat stress. In general, in days with strong and very strong heat stress, ones must expect increase in mortality (in relation to no thermal stress days) of 12 and 47%, respectively. Because of projected rise in global temperature and heat stress frequency, we must expect significant increase in HRM to the end of twenty-first century of even 165% in comparison to present days. The results of research show necessity of urgent implementation of adaptation strategies to heat in HCS.

Evidence of climatic health hazards on the general population has been discussed in many studies but limited focus is placed on developing a relationship between climate and its effects on occupational health. Long working hours with high physical activity can cause health problems for workers ranging from mild heat cramps to severe heat stroke leading to death. The paper presents the possible risk of heat hazard to outdoor workers, using the example of Warsaw. The heat stress hazard, defined by WBGT values above 26 and 28ºC and UTCI above 32 and 38ºC, is assessed from two perspectives: its spatial distribution on a local scale and its temporal changes during the 21 st century due to climate change. City centre and industrial districts were identified as the places with the greatest heat stress hazard. The number of heat stress days in a year (as predicted for the 21 st century) is increasing, meaning that heat-related illnesses are more likely to have a direct impact on workers' health.

The health of individuals and societies depends on different factors including atmospheric conditions which influence humans in direct and indirect ways. The paper presents regional variability of some climate related diseases (CRD) in Poland: salmonellosis intoxications, Lyme boreliosis, skin cancers (morbidity and mortality), influenza, overcooling deaths, as well as respiratory and circulatory mortality. The research consisted of two stages: 1) statistical modelling basing on past data and 2) projections of CRD for three SRES scenarios of climate change (A1B, A2, B1) to the year 2100. Several simple and multiply regression models were found for the relationships between climate variables and CRD. The models were applied to project future levels of CRD. At the end of 21st century we must expect increase in: circulatory mortality, Lyme boreliosis infections and skin cancer morbidity and mortality. There is also projected decrease in: respiratory mortality, overcooling deaths and influenza infections.

This paper presents an application of the Universal Thermal Climate Index UTCI to studies of regional variability in human-biometeorological conditions. The variability in question was assessed by reference to selected meteorological stations representing Central and Southern Europe, i.e. Kołobrzeg, Warsaw and Świeradów (in Poland), Prague, Budapest, Ljubljana, Milan, Rome and Athens, with the bioclimatic features characterising these localities being presented against the background of the Köppen-Geiger climate classification. In line with that classification, the first five stations are found to represent the cold climate zones (Dfb, Dfc). The last four stations are in turn located in the temperate climate zones (Cfa, Cfb, Csa). Seasonal changes in UTCI values and the frequency of occurrence of UTCI categories are discussed. Significant regional differences in bioclimatic characteristics were found between the stations representing various

This paper presents the results of research dealing with forecast changes in the frequency of occurrence of heat and cold stress in Warsaw (Poland) in the years 2001-2100, and the possible influence these may exert on mortality risk. Heat and cold stress were assessed by reference to the U niversal T hermal C limate I ndex (UTC I), for which values were calculated using meteorological data derived from the MPI-M-RE MO regional climate model, at a with spatial resolution of 25 × 25 km. The simulations used boundary conditions from the EC HAMP5 Global Climate Model, for SRES scenario A1B. Predictions of mortality rate were in turn based on experimental epidemiological data from the period 1993-2002. Medical data consist of daily numbers of deaths within the age category above 64 years (TM64+). It proved possible to observe a statistically significant relationship between UTC I and mortality rates, this serving as a basis for predicting possible changes in mortality in the 21st century due to changing conditions as regards heat and cold stress.