It's no surprise that a warmer world will look very different, especially when it comes to the planet's flora and fauna. But just how -- and where -- the environment will change is a challenging question.
A group of German researchers has run the numbers for 845 different European plant species, including 550 which grow in Germany. Their paper "Climate and land use change impacts on plant distributions in Germany," published online last week in the British journal Biology Letters, is sobering. The scientists say a 3.8 degree Celsius increase in temperature (about 7 degrees Fahrenheit) could wipe out one in five German plant species by 2080.
To arrive at their results, scientists from the Helmholtz Center for Environmental Research in Halle, the Potsdam Institute for Climate Impact Research and France's Laboratoire d'Ecologie Alpine created a complex mathematical model that took into account factors like land use, soil types and 30 different climate variables like moisture and temperature. They then plugged in scenarios drawn from Intergovernmental Panel on Climate Change reports on how much the world's temperature might increase over the next 75 years, and how that might affect land use.
The study showed a clear pattern. "Under all the scenarios, we have a decrease in biodiversity," Ingolf Kühn, a senior scientist at the Helmholtz Center who coordinated the study, told SPIEGEL ONLINE. "With an increase of two degrees, there's just a very minute decrease in biodiversity. When you look at an increase of 3 or 4 degrees, the decrease is really drastic."
By plotting the changes on a map of Germany, the researchers could pinpoint the regions and plant types most likely to lose out. Lowland and wetland areas in the northeast and southwest -- the Rhineland and Hesse, for example, and the plains and bogs of Brandenburg and Saxon-Anhalt -- will be hardest hit by changing climate conditions, in particular dry spells that upset the balance in delicate wetlands.
Another hard-hit biome would be alpine plants that rely on the chilly, damp climates of the high mountains. As Europe warms up, they will creep higher in search of suitable places to grow until they literally run out of mountain. The glacier buttercup, a delicate white and yellow flower that only blooms at high altitudes could be left with nowhere to go in the Alps of the future. "Many plant species could lose their niches in habitats such as mountains or moors," the Helmholtz Center's Sven Pompe explains.
The plants that make it could be the ones that migrate from southern Europe as the north of the continent gets warmer and drier. Kühn cites the walnut tree -- more at home right now in the Mediterranean -- as an example of a species that could thrive in a warmer, drier Germany.
Some trees that seem synonymous with parts of the German landscape -- the common spruce and many varieties of pine, for example -- rely on a very specific mix of moist, wet conditions and could be wiped off the German map by climate change.
And smaller, less-common plant species can't simply pick up and move when the mercury rises are in deep trouble. "If species have bad dispersal ability or encounter bad land use" -- suitable habitat being used for farming, for instance -- "the situation is even more extreme."
One bit of good news: The iconic German oak will most likely pull through unscathed. The tree, whose leaves and acorns grace the back of some German coins, has long been considered a national symbol. Kühn says it's actually two different subspecies, one adapted to dry conditions and one adapted to wetter soils. "We saw hardly any change (for the oak) -- it's very flexible," Kühn says.