Existing climate projection data from the ENSEMBLES Project of the European Union was applied to patterns of extreme weather and its impact on Poland. The project scientists studied many changes, including forest degradation, precipitation, extreme weather, and vegetation period — the time between sown seeds and first signs of fruit — across the European continent. In order to closely examine Poland and project its climatic future, the authors extrapolated the data from ENSEMBLES across Europe to Poland. Agriculture, water resources and human health sectors were studied based on multiple aspects of climate change to determine the transforming risks to those sectors. The result was detrimentally warmer summers and wetter winters, which shrink the vegetation period of crops as well as increases mortality of the aging human population in Poland. The study also demonstrated that evapotranspiration will greatly exceed precipitation and therefore deplete water storage in the soils. — Leah Kahn
Szwed M., Karg G., Pinskwar I., Radziejewski M., Graczyk D., Kedziora A., and Kundzewicz Z. W., 2010. Climate change and its effect on agriculture, water resources and human health sectors in Poland. Nat. Hazards Earth Syst. Sci. 10, 1725–1737.
Multi–model ensemble climate projections were used to assess the effects of climate change in Poland. The ENSEMBLES Project studied global change and ecosystems from 2004–2009. These data were evaluated by comparing two simulations a century apart over a 30–year period. The three sectors were analyzed from 1961–1990 and 2061–2090. The data from 1961 to 1990 were applied to the future to predict the coming impacts. Some of the changes are thought to be advantageous and others disadvantageous, but these sectors are likely to be adversely affected in Poland. According to the Intergovernmental Panel on Climate Change, the next two decades will bring a global warming of about 0.2°C per decade. Observations confirm that cold days have become warmer and more frequent and this trend is likely to continue. The following five characteristics of a 30–year interval were used in this study: the number of consecutive days with a high of over 35˚C and a low of less than 25˚C, the number of consecutive days with a heat index (HI) above 36, the record temperature during those 30 years, length of the vegetation period, and the number of days with little to no rainfall. Scientist examined how many days reached above 95˚F, which is very warm for Poland located in northern Europe. An HI is based on what temperature actually feels like to a human. The index comes from a temperature above 35˚C and humidity higher than 30%. The vegetation period is a window of time during which, the temperature is consistent enough for crops to begin to grow.
The first indication of climate change was found in the examination of maximum and minimum temperatures. The southeast of Poland was hardest hit by the rise in consecutive days over 35˚C. It is projected to experience 14–16 days of extreme heat at a time.
Overall, agriculture in northern Europe has been limited by temperature while southern Europe has been restricted by water. Projections for the future are positive for parts of Poland because it releases the temperature restriction on agriculture. Although, southern parts of Poland currently struggle with water storage will grapple with limited water more and more because there will be a decrease in rainfall and an increase in temperature. The majority of Poland will have less than five days of precipitation above 0.5 mm as expressed in the data.
Most of Poland will experience an increased vegetation period of between 30 to 40 days according to the authors. There are a few isolated locations where the period will lower to between 20 and 30 days. Crops grown in winter and summer experience three stages of growth, which respond to higher temperatures. The changes in crop yields of potatoes and corn were measured based on precipitation–yield field experience of the authors. They discovered that crop yield is dependent on water during the 30 days before ears of corn appear and between July and August for productive potato plants. The authors demonstrate that there will be a decrease in crop yield of 2.175 tons per hectare of potatoes and 0.539 t/ha of wheat. In comparison, the average yield between 1961–1990 was 19.18 t/ha for potatoes and 3.53 t/ha for wheat.
As agriculture is vitally dependent on water, these scientists researched the water budget in Poland. The water budget is the gap between rainfall and the evaporation of that rain from the surface of the earth. Scientists used a mathematical formula to test this during summer months. At present, evapotranspiration surpasses precipitation during the summer so water storage in bodies of water, soil and ground water decreases. The formula projects more severe summer water shortage. Evapotranspiration is based on the amount of energy required to turn water into vapor and if there is more water in the air than on the surface, the water balance dives into negative values, increasing the water shortfall. The authors used a more extensive formula involving energy categories to calculate the probability of a negative water imbalance. The probability went from .84 during the reference period to .96 in the future. That is roughly –50mm of water available whereas it was at about 32mm of water on the surface during the reference interval.
Two energy ratios were calculated to measure evapotranspiration; Energy Ratio 1 (ER1) illustrated the actual degree of drought; the higher the value of ER1 the worse the drought. Energy Ratio 2 (ER2) indicates the probable degree of drought by showing how much water is needed to take full advantage of the agricultural environment. The two datasets demonstrate that the drought will increase by 100%. A spatial map of each dataset illustrates that there are about 27 cells with an ER1 value of less than one during the observation period. There will be only 10 cells with a value less than one in the future period. The ratio is projected to increase to about 1.5 in central Poland. This means that rainfall will only make up for half of the water evapotranspiration is taking away.
These sectors both influence the third sector of the study, human health. The polish population is rapidly aging. More heat waves are projected and heat related illnesses are very common when extreme heat lasts more than two days. The coming heat waves will last between 14 and 16 days. The extreme weather becomes fatal when the air does not cool down at night. If humidity is also high, the body cannot cool itself off effectively using the evaporation of sweat. According to this paper, both numbers of Poles older than 65 years are going to increase, days above 32˚C. This paper used the proposed threshold of HI=36, and also studied senior–discomfort days by using an index of HI=32. The number of senior–discomfort days is projected to increase 8 times over in the next 100 years.
The most successful response to these findings is to adapt. The agricultural sector requires practices such as crop rotation, advanced sowing dates due to vegetation periods and the introduction of drought resistant strains. The water usage sector needs more water storage such as manmade lakes, mulching fields, and groundwater aquifers. To prevent a decline in human health, people must have heat warning systems, air conditioning such as swamp coolers and stone buildings, and a strong education in heat related illness prevention. This study projects the future of Poland and its inhabitants based on a successful European climate change model. Poland is experiencing less water and drier soils and therefore producing fewer crop yields. Without staples and a water deficit, human health is impacted. Those most influenced by it are the aging population of Poland.