Future Imperfect: Climate change and adaptation in the Carpathians

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Figure 10: Change in the number of winter days per year (daily maximum < 0ºC, up) and hot days per year (daily maximum ≥ 30ºC, down) in the Carpathian region in the period of 1961–2010 (source: CARPATCLIM).

Figure 11: Change in the start date of the growing season 5ºC (up) and 10ºC (down) in days in the period of 1961–2010. Significant changes at 90% level are marked with dots (source: CARPATCLIM).

that the number of winter days decreases every- where in the Carpathian region with very few excep- tions. The greatest decline can be seen in the north- west Carpathians (a reduction of 18 to 20 days between 1961 and 2010). In the south and east Carpathians, a small increase appears. The change in the number of hot days correlates strongly with topography – fewer hot days are seen at higher lev- els in the mountains than at lower altitudes. The increase of hot days is higher in river basins, espe- cially in the territory between the Danube and Tisza rivers (18 –22). The Transylvanian basin shows slower increase in hot days. The South and East Car- pathians showed the largest growth in the number of hot days (over 24 between 1961 and 2010).

These changes are already having an effect on the environment, economy and human health. For ex- ample, the vegetation growing period starts earlier (Figure 11). The changes are larger and more signif- icant at the basic temperature 5°C, than at 10°C. Vegetation growth has been starting about 15-20 days earlier in the first decade of the 21st Century, than in the middle of the 20th Century. In summary, increasing temperatures are expected throughout the Carpathians. In summer the highest increase is projected in the South-eastern part and lowest in the North-western part of the region. Mod- el studies largely agree in projecting an increase of winter precipitation and a decrease of summer

precipitation. Although the mean annual values of precipitation will remain almost constant (with a small annual increase in the Northwest and de- crease for the rest of the region that is strongest in the Southern part of the Carpathians), decreases in summer precipitation are projected of above 20 % and winter precipitation is projected to increase in most areas with 5 to 15 %. The large and opposite trends for different seasons imply that the annual distribution of precipitation can be restructured. The summer season may become the driest, and the winter is expected to be the wettest season by the end of the 21st century.

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FUTURE IMPERFECT