Although the climate in Poland varies greatly, an analysis of long-term observations of air temperature shows an occurrence of certain regularities. A graph of the average annual temperature in Warsaw from year 1781 to 1990 (GRAPH illustrating mean annual air temperatures and annual precipitation totals in Warsaw ), clearly demonstrates an upward trend, which indicates a slow but systematic warming of the climate. Similarly an analysis of the graph of average annual temperatures over the last forty years shows a discernible increase, particularly from the beginning of the second half of the 1980s. Warm winters and springs are the main contributors to this phenomenon. The results of studies of deviations of the average annual air temperature from the average for the period from 1951 to 1980 are very similar for both the northern hemisphere and Poland. They indicate much higher temperatures in the second half of the 1980s in comparison to the average, as well as a further upward trend.

Precipitation over the whole country follows a different trend. From 1931 to 1980 in urbanized and industrialized areas there was an increase of the total amount of precipitation, while in the rural areas there was a downward trend in precipitation (MAP illustrating trends in annual precipitation totals). In the 1980s a downward trend of the total amount of precipitation occurred throughout all areas of the country. Studies of Cracow’s climate indicate that from the middle of the 1970s the following changes in the climate occurred: decrease in the amount of clouds (connected with a similar tendency in all of Europe) and a fall in the amount of insolation due to increasing atmospheric obscurity and a worsening of city ventilation conditions.

Over the years city temperatures grew faster than temperatures observed globally. It is undoubtedly a result of an overlapping of both factors, urbanization and industrialization of urban areas as well as global warming.

This tendency will continue in the future, if both the process of urbanization and deforestation proceed into the next century. This means that the unfavourable changes of the climate caused by humans will be exacerbated. An expected further increase of concentration of greenhouse gases in the atmosphere will lead to an increase of air temperature. The size of this increase depends on economic strategy, especially on how the power-generating industry develops world-wide. It is estimated though, that an increase of the average annual temperature to the end of the next century should range from 2 to 4 degrees. In a scenario of predicted climate changes in Poland to year the 2000, average annual air temperature are supposed to grow, mostly as a result of the increase of temperature during winter. At the same time, a slight increase of precipitation in the winter should be expected with a decrease in precipitation during other seasons. This means that a decreasing trend of annual precipitation should continue to the end of this century.

Another problem that will occur in the future is the further decrease of ozone in the stratosphere. In light of the long lifespan of freon particles in the atmosphere (up to 150 years) it cannot be expected that concentrations of freon gases in the atmosphere will fall. This is why in 1985 on the initiative of the United Nations Environment Program, the Vienna Convention for the Protection of the Ozone Layer was signed. In 1987 the Montreal Protocol was enacted. This document defines the strategy of gradual reduction of gases that destroy stratospheric ozone. Poland ratified this convention in 1990.

	Chapter Homepage	SOE Homepage	GRID-Warsaw Homepage	MEP Homepage