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Project results

Regional Climate change – Analysis and outlook

The spatial variability of the mean air temperature is mainly influenced by the orographic conditions in the project region. Observational data from German, Polish and Czech weather services show steadily increasing temperatures in the decades from 1971 to 2010, albeit with varying intensity.

Temperature shows the strongest positive trend in spring and summer. In winter, no significant trend is observed. The trend correlates with an increasing number of summer days, hot days and tropical nights, and increasing heat stress, while cold days, frost days and ice days and accordingly cold stress show decreasing trends. Heat stress in particular shows a significantly negative effect on the suitability and quality of leisure and tourism conditions.

The results of the agro-meteorological analysis also illustrate an increasing persistence of the thermal growing season and increasing growing degree days. In contrast, Selyaninov's hydrothermal coefficient correlates with the increasingly drier conditions in the project area. Negative effects like water deficit, droughts and heat waves or extreme events such as floods on agricultural production as well on forestry are currently observed.

Based on climate projections until 2100 it is assumed that the current trend will continue in the future. Especially under the scenarios A1B and RCP8.5, a further rise in temperature up to 4 °C vs. 1971-2010 is expected. Moderate increases are projected under RCP2.6. Winter sports tourism could be particularly adversely affected by this development. Increased heat stress in the lowlands of the project area could also have a negative impact on tourism and lead to a shift of suitable bioclimatic conditions during the year. Agriculture and forestry must be adapted as well as the tourism to the changing conditions. For this purpose, adaptation measures are necessary, which can use the results of temperature trends obtained in the project KLAPS as a foundation.

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Yearly Mean of air temperature [°C] in the project area (1971-2000) Icon vorheriges Bild Icon nächstes Bild Icon Bild vergrößern

Yearly Mean of air temperature [°C] in the project area (1971-2000)
(© LfULG)

Yearly Mean of air temperature [°C] in the project area (1971-2000) Decadal variation Yearly Mean of air temperature [°C] in the project area (1971-2010) Change of temperature Hot days 2021-2050 and 2071-2100 vs. 1971-2000 Frost days 2021-2050 and 2071-2100 vs. 1971-2000 Deposition budget 2000-2030 Sulphur deposition for the climate scenarios A1B, RCP2.6 and RCP8.5 and the time slices 2021-2050 und 2071-2100

Air pollution

The border region of South Saxony, Lower Silesia and Northern Bohemia was long time characterized by extremely high levels of air pollution and known as the "Black Triangle". Since 1990, however, a decrease in sulphur and nitrogen emissions has been measured. Rising environmental awareness and political and economic changes in Central Europe mainly contribute to this development. To evaluate the current situation of load of different ecosystems, the dispersion model FRAME was used. FRAME provides spatial information about the concentration and deposition of atmospheric pollutants for the present (2000-2010) and future considering emission projections to 2030 and climate projections to 2100. For the present results show decreasing deposition of oxidised sulphur and nitrogen, while the deposition of reduced nitrogen remains at a constant level. In the future, this trend is expected to continue. Based on the used climate scenarios (A1B and RCP8.5) decreases in sulphur and nitrogen deposition at the end of the 21st century, compared to 2010 are modelled. This is essentially due to a projected decrease in the annual sum of precipitation. Under the RCP2.6 scenario, the climatic influence on the deposition height is negligible. It can be assumed that reduced nitrogen will be the main source of nitrogen deposition in the Polish-Saxon border region.

Critical Load

Traditionally, limits of air pollutants have great importance on providing new environmental objectives. The principle of ecological load limits, the so-called Critical Load, has proven itself to establishing load limits. Measurements of recent decades to reduce air pollution are reflected based on ecological load limits in the project area. Load limits for acidification are exceeded by 10 % of the area of forest and other natural ecosystems only. According to the forecasts of future sulphur deposition almost all ecosystems will be protected from acidification by 2030. In contrast, the proportion of the area, which is affected by the risk of eutrophication is still very high with 60 % in 2010, despite significant reductions in nitrogen. The projected decreases in nitrogen emissions by 2030 will decrease this percentage initially. In addition to the decreasing trends of pollutants in the project area, the present results show that climatic changes have a major impact especially on the critical load for protection against eutrophication. Thus, climatic changes should be considered mandatory in future clean air policy.