The spring starts earlier and earlier

Strictly speaking, the calendar started of spring just last week. However, it was felt already in February because, as a persistent high-pressure weather, the Switzerland brought an unusual amount of sunshine and warm temperatures. This year, the country recorded one of the ten mildest February months since the start of the measurements. On the southern side of the Alps, the hair dryer provided even in January that it was in some regions so mild as never before in 150 years.

The has an effect on the development of the plants. For the temperature is a key factor. Shortly after Christmas in Lugano-uniform hazel were measured pollen concentrations – the fourth-earliest date since the beginning of the Measurement. "The country flourished hazel bushes about eight days rather than in the middle," says Regula Gehrig from Meteo Schweiz.

This Trend continues to 2019: The time at which the plants from the winter awake, pushes more and more to the front. Since the 1990s, the spring has begun in comparison to the long-term average (1981-2010) is almost always early or very early. to determine

the spring index, recorded Meteo Switzerland at some 80 stations of the measurement network, when the plants begin to sprout. The evaluation clearly shows, how strongly the impacts of climate change on the Vegetation. The alder, for example, blooms today, 13 days earlier than 50 years ago, hazel, around 15 days earlier.

"Not all plants react the same to changes in temperature," says Gehrig. The show, the two longest series of measurements, the Meteo Schweiz to rely on. As is observed in the city of Geneva since 1808 a horse chestnut tree, which had up to the year 1900 is often only in April of his blade to the outbreak. Then there is a clear Trend towards earlier onset, so that the leaves unfold today in March or even in February (see weighted average).

The main reason for this development is the increase in global temperature. Structural changes in the environment, and a stronger warming in a city like Geneva, but play also a role. "Basically, it is in cities of 1 to 2 degrees warmer than on the Land. Therefore, the plants flowering tends to be earlier," explains Gehrig.

That shows in comparison with a wild cherry tree in Liestal, near Basel, on the edge of a forest, in a rural environment. He has been studied since 1894, and is in bloom now, also earlier than in the first decades of the observation. The clear Trend towards earlier flowering but not until the year 1990, much later than in the case of the chestnut tree in Geneva.

Previously started the cherry-tree to blossom about the middle of April, now is already in the beginning of month or even in March, the case, as is probably the case this year. Gehrig is expected that the first message from Liestal in the next few days. Another cherry in the area on may 21. March flowers worn.

"The rhythm between plants and animals does not match."Regula Gehrig, Meteo Switzerland

Many people are happy when spring comes and the temperatures rise. Most of the shrubs and trees sprout in Switzerland, earlier, for the Ecosystem with negative consequences. "The rhythm between plants, insects and birds that no longer matches," says Gehrig. "Trees don't bloom already, when the insects are still there. Then there is less pollination and therefore fewer fruits."

plants and animals are dependent on each other. And the shift of the seasons messes with relationships between species. If plants which need insects as food after Hatching, no longer or not yet to grow, starve the animals and the absence of the birds as food for their brood.

"climate warming increases the risk of frost damage in trees."ETH Zürich

another Problem is the changing face of the spring. In April, cold polar air often causes a fickle weather, and plants, according to Gehrig, "and are the most vulnerable during the flowering or leaf unfolding". Researchers from the Zurich ETH have recently found that with a warm spring the risk of frost damage in trees and bushes may grow. The plants sprout namely early, and are protected from surprising cold in the late spring worse.

But it has consequences also for the people of the shifting of the seasons. According to a study by the University of new castle and the WSL Institute for snow and avalanche research, snow and so the ski season is now almost 40 days shorter than in 1970. Pathogens and pests in the home were not here yet, can survive with the warm temperatures, and spread. In addition, the Pollen sets in earlier. For Allergy sufferers, that means even earlier, sneezing, rubbing the eyes, snorting. If climate change continues as in the past, could be exacerbated all the more.

(editing Tamedia)

Created: 28.03.2019, 16:34 PM