KliO – Climate Change and Fruit Growing in Germany | Umweltbundesamt

To analyse climate change for the whole of Germany, at the level of the federal state and for the fruit growing regions mean values of the IPCC emission scenarios B1 and A1B of the regional models REMO and WETTREG are used. For the comparison of the model control runs with observational data and analysis of recent climate changes (interpolated with Universal Kriging 2nd order, resolution 10 x 10 km) measured values of the DWD (station data)are used. To create phenological models, regional phenological observations of fruit trees of the DWD are used (e. g. beginning of blooming of woody plants and ripeness of fruits). To verify the models observations from the fruit growing regions are used: for example, data from the Altes Land and the Lake Constance region.

Compared to the current climate (1961-2000) the evaluations of the regional models for Germany show a significant increase in mean annual temperature for the period 2071-2100 of 1.9 (B1) and 3.0 ° C (A1B). Seasonal increasing air temperatures at the end of this century (2071-2100) will be as follows: In winter +3.9, in autumn +3.5, in summer +3.2 and in spring + 1.8 ° C (scenario A1B). Especially during winter, summer and autumn temperature changes in southern Germany will be larger than in the north of the country. There are no significant changes in annual precipitation in all scenarios. Tendentially only in the A1B scenario a significant increase in winter precipitation and decrease in summer precipitation can be recognized.

Due to the ongoing earliness of the onset of vegetation growth and the delay of the end of growing season the thermal growing season is extended up to a maximum of 72 days (A1B). As already happening, the late frost will occur 14 (B1) to 21 (A1B) days earlier in the period 2071-2100. In contrast to the current situation, the first early frost in fall will be 19 (B1) to 33 (A1B) days later. Thus the frost-free period will be extended by a maximum of up to 54 days (A1B).

Temperature and precipitation (seasonal differences), extreme events (e. g. late frosts) and -values (e. g. minimum temperatures)

Consequences of recent climate change are recognizable already in the fruit growing sector. First signs are shifts in vegetational development such as earlier beginning of blooming of fruit trees in Germany or the general extension of the growing season by about 10 days in the last decades, which is detectable in almost all of Europe. Associated with an ongoing earlier beginning of blooming, there is an increasing danger of late frost damage, which is already observed in some regions of Europe. Frost during the blooming period of woody plants is one the most dangerous weather events, destryoing the harvest of a whole year in extreme cases.

Since the 1990s an increase of fruit pests (e. g. codling moth) in fruit plantations is observed as well. Changes in climate may increase the risk of infestation of pests, resulting in the need for new control strategies.

At the Lower Elbe a phenological tendency to an earlier onset of blooming and harvesting in correlation with rising temperatures could also be detected for the most important animalistic pest of apples orchards (codling moth: Cydia pomonella). A significant earliness of the onset of moth flight is observed. Also the further development of this insect responds strongly to the air temperature. Thus a second generation of moths was detected in the warm summer of 2006, but not in the cooler summer of 2005, which led to a feeding damage shortly before harvesting.

Vulnerability means the damage risks in specific economic sectors, which depend on both the regional impacts of climate change, as well as the possible degree of adaptation in the considered sector. The vulnerability is analyzed for the main fruit growing areas in Germany.

Compared to crop farming, where adaptation measures can be effective relatively quickly, longer-term aspects are important to consider when starting or converting orchards. Returns are not realised before 3 to 6 years after the initial investments. Depending on the type of fruit capital recovery can take as long as 25 years. Therefore, changes in the variety must be carried out early.

Climate changes do not only mean risks but also opportunities. It is necessary to minimize risks by establishing appropriate adaptation measures (late frost risks, shortening the ripening time, water shortages, pest infestations, etc.) and make the most of the opportunities offered (extended growing season, higher temperatures). This can be done by choosing appropriate types of fruits and species. For example, stone fruit which is generally sensitive to cold would thus benefit from a warmer climate.

For pest infestation by codling moth pheromone-based mating disruption technique can be applied. If it is possible to stabilize the infestation of codling moth by the establishment of this technique and the optimization of the prognoses, especially organic producers will be given the opportunity to adapt to changing production conditions caused by climate change. The use insecticides can be minimized as well.

The potential for sustainable development in fruit growing will be considered. This applies to fruit growing as form of land use, as well as the assurance of establishments, jobs and income in this sector.