Climate Change Predictions: A Tropical Germany by 2100?

By , Sebastian Knauer and Horand Knaup

Tropical nights in Bavaria, torrential rains elsewhere? Scientists have now come up with the most detailed predictions ever of the expected consequences of climate change in Germany.

Kaufbeuren, 90 kilometers west of Munich, is like many other small German cities. With a population of 42,000, the town boasts a small pedestrian shopping zone, a handful of ice cream parlors and its own highway bypass. Life is normal in Kaufbeuren -- for now.

Kaufbeuren could become famous in the second half of this century -- when it attains the dubious distinction of becoming the city with the greatest temperature increase in Germany. Its residents face the prospect of hot summer days, mild tropical nights and Mediterranean winters.

The average daytime temperature throughout the year will likely increase there by more than 2.5 degrees Celsius (4.5 degrees Fahrenheit) compared to today. As small as this figure may seem, it would mean that the climate in Kaufbeuren would almost resemble that of Mediterranean regions.

What sounds like science fiction is the outcome of a new study by Germany's Federal Environment Agency (UBA), which was commissioned by the German government. The firm Climate & Environment Consulting Potsdam created a model called "WettReg" for the UBA to illustrate the possible effects of climate change on German regions between 2071 and 2100. UBA Director Andreas Troge, summarizing the results of the report, says: "We must all change our environmental behavior considerably."

The study analyzed millions of pieces of data from German weather stations and international climate researchers, as well as studies performed by the Hamburg-based Max Planck Institute for Meteorology. Based on the study's extrapolations, every German citizen between the Baltic Sea and the Alps can now see how the climate will likely change in his or her region.

As with a weather report, not every aspect of the prognosis will come about, but there appear to be some clear trends on the horizon. It seems highly likely that hot summers such as those the country experienced in 2003 and 2006 will become the norm. Germany's northeastern and southwestern regions will become noticeably drier, so much so that grasslands could develop in parts of the northeastern states of Mecklenburg-Western Pomerania and Brandenburg. Temperatures are also likely to rise significantly in Saxony, Baden-Württemberg and the Alpine foothills.

High levels of precipitation can be expected in low mountain ranges such as the Eifel, Hunsrück, Odenwald and Spessart mountains. According to the simulation, by 2100 these areas could see increases in winter rain of up to 80 percent compared to earlier decades. "Climate change will pervade all aspects of life," says Manfred Stock of the Potsdam Institute for Climate Impact Research, which contributed its own data to the study.

The experts describe essentially two possible scenarios of climatic development. The first is a pessimistic, "growth-oriented" scenario, in which the emission of gases like CO2 will initially increase and then remain constant at a high level. The second is an optimistic, "sustained" scenario, which, in contrast to the more pessimistic view, is based on the assumption of a long-term reduction in emissions. But the computed temperature curve also climbs significantly in the second case, with palpable consequences. The northern state of Brandenburg could turn into a wine-growing region, and tourism on the Baltic Sea would boom.

Many farmers already realize today that adjustment is necessary. In Brandenburg, where precipitation has been declining for years, farmers had to make do last year with only 300 millimeters (12 inches) of precipitation, compared to normal levels of 700 millimeters (28 inches) in the past. In places where farmers currently grow wheat, more heat-resistant grains like millet or corn could soon be a better bet. Grain production in northern Germany will increasingly suffer from hail and major storms like "Kyrill." Farmers throughout the country will face greater challenges from pests.

Winegrowing will also change, according to the study's calculations. In the Kaiserstuhl region of southern Baden-Württemberg, in Rheingau and in Franconia, vintners could increasingly be forced to switch to red grape varieties. Even the most favorable vineyard locations would face problems, as higher temperatures and humidity create a more beneficial environment for pests, while on steeper slopes heavy rains would increase erosion.

Water management systems would also have to adjust. In all likelihood there would be a noticeable reduction in the overall flow of natural water in Germany. Average water levels would decline, even in major rivers. "Anyone who expands the Elbe for shipping today will have to come up with an explanation when the river ceases to be navigable one day," says UBA director Troge. Groundwater levels are also expected to decline in many regions, so that a series of consecutive heat waves could lead to major shortages of drinking water in heavily populated areas.

Conversely, heavy rain would likely become a daily occurrence. Because this type of precipitation drains off quickly, it does little to augment the groundwater supply. Instead, it will cause periodic flooding in city sewage systems and treatment plants. The previous "100-year flood" levels along major rivers like the Rhine, the Elbe and the Oder would be reached much more frequently than in the past.

Health risks are among the most serious consequences of climate change. In cities like Freiburg, Karlsruhe and Cologne, which are located in so-called heat islands, average temperatures have already increased by measurable amounts. The August 2003 heat wave offered a taste of what could come. According to estimates at the time, there were 7,000 premature deaths throughout Germany during the heat wave. In places like Arkona on the Baltic Sea and Freiburg im Breisgau, the number of "tropical nights" -- when the temperature remains above 20 degrees Celsius (68 degrees Fahrenheit) -- would more than double.

Heat-loving pests are already on the rise today. Disease-carrying insects such as sandflies, which were unheard of in Germany 20 years ago, are already thriving. According to the experts at the UBA, even the pathogen that transmits the feared tropical disease malaria could stand a good chance of surviving north of the Alps in a few decades. Meningitis, which is transmitted by ticks, has already appeared in northern Germany.

The kinds of winters that were the rule 40 years ago will probably become a rarity. Without snowmaking equipment, skiing in Germany's central mountain ranges will be impossible by 2100, and even most Alpine ski regions will be forced to switch to artificial snow. In the Bavarian resort town of Garmisch-Partenkirchen, for example, there will likely be 40 fewer days when the temperature drops below freezing than in 1990.

The insurance industry has already formed a precise picture of the new Germany. According to its calculations, close to 90 percent of major claims filed in Europe since 1980 were attributable to weather-related events such as storms, flooding and heat waves.

The science of environmental protection is constantly coming up with new developments, and humanity is adaptable. Does this mean that the consequences of climate change could end up not being so dire after all?

Not quite. "The study is a warning signal for climate policy," says Michael Müller, the junior minister for the environment. As a member of the German parliament's Enquete Commission on climate change in the 1990s, Müller helped develop Germany's target of a 30-percent reduction in CO2 emissions. "Even if all climate policy specifications are in fact implemented," says Müller, "we will no longer be able to change any of the consequences of global warming until 2050."

Translated from the German by Christopher Sultan

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