As a result of climate change, weather extremes like storms, rainfall extremes, floods and droughts are expected to occur more frequently. Such weather extremes can cause massive crop failures locally, but so far it is impossible to make reliable forecasts regarding their future occurrence. However, projections of temperature and rainfall can be calculated and, on a larger timescale, these parameters influence crop yield more strongly.
Using the scenario-model STAR II Friedrich-Wilhelm Gerstengarbe from PIK calculated that the average annual temperature in Eastern Germany could rise by up to 2.7 degrees Celsius (4.8 degrees Fahrenheit) by the middle of the 21st century. Average annual rainfall is projected to decrease only marginally. According to the authors a shift of rainfall patterns is to be expected. Summertime rainfall will probably decrease while wintertime rainfall is likely to increase. This trend can already be monitored today and will continue as a tendency into the future. According to the projections this development will be interrupted infrequently, though, by relatively humid phases with comparatively high amounts of rainfall during the summer months.
Based on this scenario, Frank Wechsung and Andrea Lüttger have evaluated crop yields of maize and wheat in Eastern Germany. On average, yields will probably remain stable under these climatic conditions for the next 20 to 30 years, they report. A significant crop loss is to be expected by the middle of the 21st century, especially at locations in the eastern lowlands distant from the coast. The losses will be greater in the cultivation of maize than that of wheat. However, the increase in atmospheric concentration of carbon dioxide (CO2) might compensate part or all of these losses. Finally, due to the fertilizing effect of this greenhouse gas, yields of winter wheat can be expected to increase and yields of maize to decrease only slightly due to water stress until mid of the century. Ideal nitrate provision is a necessary precondition for the CO2 fertilization to come to its full effect, though. This could impose additional costs on farmers.
“Short-rotation coppicing of aspen is a good cultivation alternative for farmers to secure future incomes”, says Petra Lasch, one of the authors and a member of research domain “Climate Impacts and Vulnerabilities” at PIK. Crop yields of fast growing aspen (Populus tremula) are expected to increase under the presumed changes of climate. Rising profits are anticipated even for regions with sandy and light soils with low water retention capacities that are generally affected more strongly by climate change. Agrarian wood benefits more from rising temperatures and a higher concentration of CO2 than other crops.
The Potsdam Institute for Climate Impact Research analyses and describes both the opportunities linked with climate change as well as the risks, states the Institute’s director John Schellnhuber in his introduction to the study. By outlining both positive and negative consequences for Eastern Germany’s agriculture, the analysis fulfills this goal. The good news for Eastern German farmers is that it is still profitable to invest, Schellnhuber writes, “even under the conditions of climate change”.
The authors reach the conclusion that the value of farmland for the production of biomass will increase rather than decrease. Global request for supply would have a positive influence on the market price. Even if crop yields in some parts of Eastern Germany fell, monetary damages would probably be overcompensated by increases in farmers’ incomes.
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