1. POSSIBLE IMPACTS OF CLIMATE CHANGE ON LAKES AND WETLANDS IN HUNGARY Sándor Szegedi*- Zoltán Karácsonyi** - Károly Tar*-and Andrea Kircsi* *Department of Meteorology,University Of Debrecen **Centre for Environmental Management and Policy University Of Debrecen 4. LAKEPROMO SEMINAR 17.05 – 18.05.2006 Pühajärve, ESTONIA University of Debrecen, HUNGARY Centre for Environmental Management and Policy

2. Introduction – changes in the hydrological conditions in the Carpathian Basin during the last 150 years Since the 1850’s landscape and hydrology of the Carpathian Basin has altered significantly due to regularization of riverways and lakes. Before the regularization works there were waste areas of wetlands in the low-laying regions of the Carpathian Basin. Permanently and periodically (2-6 months in a year) flooded areas occupied more than a quarter of the area of the country. 4. LAKEPROMO SEMINAR 17.05 – 18.05.2006 Pühajärve, ESTONIA University of Debrecen, HUNGARY Centre for Environmental Management and Policy

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4. During the regularization works (from 1846) river meanders were cut off, periodically flooded areas and swamps along rivers and lakes were drained. Only along the River Tisza 111 meanders were cut off. Dams were built in order to prevent floods and to gain agricultural land. More than 6,400km of dams and nearly 12,000km of canals were built. Consequently, the extent of wetlands decreased remarkably (from 25,000km 2 to 1,200km 2 from total 93,000km 2 area of the country). Wetlands have survived only between dams and in cut off meanders of the rivers, which have become occupied by lakes and swamps. 4. LAKEPROMO SEMINAR 17.05 – 18.05.2006 Pühajärve, ESTONIA University of Debrecen, HUNGARY Centre for Environmental Management and Policy

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7. Climate change in Hungary – Today… 4. LAKEPROMO SEMINAR 17.05 – 18.05.2006 Pühajärve, ESTONIA University of Debrecen, HUNGARY Centre for Environmental Management and Policy

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9. Trends of climate elements show considerable changes within the time span of meteorological observations. Since the establishment of the meteorological observation network (1870) in Hungary there has been an increase of the annual mean temperatures of 1°C, while the amount of annual mean precipitation has decreased by 100mm in the West and 50mm in the East. 4. LAKEPROMO SEMINAR 17.05 – 18.05.2006 Pühajärve, ESTONIA University of Debrecen, HUNGARY Centre for Environmental Management and Policy

10. Trends of precipitation in some weather stations representative for the Great Hungarian Plain and the watershed of Lake Balaton during the 1955-2000 period compared to the annual mean of the 1961-1990 period. 4. LAKEPROMO SEMINAR 17.05 – 18.05.2006 Pühajärve, ESTONIA University of Debrecen, HUNGARY Centre for Environmental Management and Policy

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12. …and tomorrow The main problem is that little is known about the regional effects of climate change, since global scenarios for climate change and Global Circulation Models have a resolution of several hundreds of kilometers. For this reason, downscaling of global scenarios or GCM outputs is necessary for regional forecasting. Climatological variables at a given time and location are strongly influenced by atmospheric circulation patterns, therefore climatic variability may be related to changes of atmospheric circulation. 4. LAKEPROMO SEMINAR 17.05 – 18.05.2006 Pühajärve, ESTONIA University of Debrecen, HUNGARY Centre for Environmental Management and Policy

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14. Former studies have found strong relationships between daily and monthly changes of water budget elements (surface inflow, precipitation, evaporation) and large scale circulation patterns (CP). Outputs of T21 GCM of Max Planck Institute of Hamburg for 1×CO 2 and 2×CO 2 concentrations have been used for the simulations. Using a semiempirical downscaling approach, changes of atmospheric circulation patterns, their occurrence, persistence and transition probabilities have been analyzed and linked to changes in the water budget elements. 4. LAKEPROMO SEMINAR 17.05 – 18.05.2006 Pühajärve, ESTONIA University of Debrecen, HUNGARY Centre for Environmental Management and Policy

15. Climate change: Lake Balaton and the Great Hungarian Plain The largest lake of Hungary and Central Europe is Lake Balaton. Its area is 600km 2. It is a shallow lake similarly to all other lakes in Hungary. Its average depth is only 3m (11m is its maximal depth), what makes it extremely sensitive to climate variability. Since Roman times there had been severe fluctuations in the water level of the lake. During the last decades of 20 th century a strong decrease in surface inflow occurred what made some mitigating measures inevitable. 4. LAKEPROMO SEMINAR 17.05 – 18.05.2006 Pühajärve, ESTONIA University of Debrecen, HUNGARY Centre for Environmental Management and Policy

16. Lake Balaton water supply - Extremely low water level (reason: 2000-2003 low precipitation in the watershed) - Water supply – necessary? - Source: riverine (Danube, Mura, Rába, Dráva) or karst-water? - strong civil interest (for and against) - high touristic importance - strong local support (economic reasons) Strategic environmental assessment Outcome: the plan is given up primarily for ecological reasons. Due to the favourable weather, the lack of water ceased in 2005, and in 2006 there is water surplus Municipality Board meeting on a dune (August, 2002.) 4. LAKEPROMO SEMINAR 17.05 – 18.05.2006 Pühajärve, ESTONIA University of Debrecen, HUNGARY Centre for Environmental Management and Policy

17. One of the most serious challenges of 20 th /21 st century from the aspect of hydrology is climate change. Processes linked to alterations of climate may have strong impacts on surface waters. For this reason examinations have been carried out to trace and model those impacts on the elements of the water budget in the watershed of Lake Balaton and the Great Hungarian Plain, which are the most sensitive regions of Hungary from the aspect of climate change. 4. LAKEPROMO SEMINAR 17.05 – 18.05.2006 Pühajärve, ESTONIA University of Debrecen, HUNGARY Centre for Environmental Management and Policy

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19. Model results show that there will be relatively strong changes in the water budget elements in the case of 2× CO 2 scenario. Evaporation will increase by 3-4% in the summer season. The amount of precipitation on rainy days will increase but the number of rainy days will decrease. On the other hand in the winter season the Southern part of the watershed will be a bit wetter, while the rest of the region will be dryer. 4. LAKEPROMO SEMINAR 17.05 – 18.05.2006 Pühajärve, ESTONIA University of Debrecen, HUNGARY Centre for Environmental Management and Policy

20. Anomalies of the amount of precipitation on rainy days for the watershed of Lake Balaton simulated by a stochastic embedded model for 2×CO 2 climate (Bartholy, 2004). 4. LAKEPROMO SEMINAR 17.05 – 18.05.2006 Pühajärve, ESTONIA University of Debrecen, HUNGARY Centre for Environmental Management and Policy

21. The amount of precipitation of rainy days will decrease as well. No significant changes are detected in the probability distribution of dry period duration. As a consequence of changes in evaporation and precipitation inflow and uncontrolled volumetric change may be altered strongly. As a result lakes and wetlands may become even more sensitive to changes of climate elements in the future. 4. LAKEPROMO SEMINAR 17.05 – 18.05.2006 Pühajärve, ESTONIA University of Debrecen, HUNGARY Centre for Environmental Management and Policy

22. Complex Habitat Rehabilitation of the Central Bereg Plain, Northeast Hungary Since 1990 projects has been launched for revitalization of wetlands in the Danube and Tisza valley (in the Great Hungarian Plain) as well. Our department is involved in a project carried out by the Hortobágy National Park. The endangered wetlands of the Central Bereg Plain are located in the least developed region of Hungary next to the border with Ukraine. There are different valuable habitat types from active raised bogs to several forest habitats. 4. LAKEPROMO SEMINAR 17.05 – 18.05.2006 Pühajärve, ESTONIA University of Debrecen, HUNGARY Centre for Environmental Management and Policy

23. Raised bogs evolved under very specific microclimatic conditions in the Great Hungarian Plain, and represent the southernmost relict of this type of ecosystem in Central Europe. The LIFE project area has suffered long term degradation by human activities. The main causes are desiccation by agricultural drainage during the socialist era, increasing eutrophication by agricultural chemicals, erosion from surrounding arable areas and a lack of renewal of the wood stock in cultivated forests. Over 430 ha of wetlands will be restored by water retention from precipitation. 4. LAKEPROMO SEMINAR 17.05 – 18.05.2006 Pühajärve, ESTONIA University of Debrecen, HUNGARY Centre for Environmental Management and Policy

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25. By the end of the project, the restored hydrology of the area should provide the ideal microclimatic conditions to help these wetlands recover in the dry pannonic climate. At the same time, scientific monitoring will lay the basis for the long-term maintenance of the rehabilitated areas. As a part of the monitoring the aim of our measurements is to detect the special microclimate features of the study area using vertical profiles of climate elements. 4. LAKEPROMO SEMINAR 17.05 – 18.05.2006 Pühajärve, ESTONIA University of Debrecen, HUNGARY Centre for Environmental Management and Policy

26. Thank you for your attention! 4. LAKEPROMO SEMINAR 17.05 – 18.05.2006 Pühajärve, ESTONIA University of Debrecen, HUNGARY Centre for Environmental Management and Policy