Climate change affects our natural world

Earth‘s future is challenged by a new human-produced threat

Climate change has always played a role in our planet´s development. Nature has therefore already gone through a long process of adaptation. Why is the story different now? We now know that life itself in all its richness and variety - or its biological diversity - is threatened. What are the main reasons for that? Is climate change really the only driving force?

Compared to earlier changes in the climate, the extreme state of degradation of the natural world we find in many regions of the world today, along with the speed climate change is taking place, account for the most important reasons. It is necessary to understand that we too are a part of the natural world we live in just as other living beings are. There is, however, a limit to mankind´s capacity to adapt to changes in the environment which humans have influenced more and more over the centuries. Image In an already degraded natural environment climate change is an additional stress factor for ecosystems and species.

In addition to intensive land-use, pollution and an excess use of natural resources that have become standard practices, the planet faces a further human-induced threat: the rapid acceleration of climate change and further devastation of our natural living conditions.

Temperatures are rising worldwide, climate zones are shifting polewards, the distribution of rainfall is changing. Climate zones shifting polewards and species and their habitats following this trend or moving to higher regions, are examples for nature trying to adapt to these new conditions. Rising temperatures also cause seasonal rhythms to change: the growing season starts earlier, and from year to year characteristic signs of spring, flowers in bloom and nesting birds, appear earlier.

Various species such as the Large Copper, the Bea-eater or the Praying Mantis have succeeded in colonizing new habitats in Germany. In order to support this trend it is crucial, however, that an ecological network of habitats is available whereby habitats themselves should be of considerable size. If that is not the case, habitats that otherwise would be suitable for migrating species will remain isolated. To ensure that this insight is put into practice NABU has published its Federal Wildlife Migration Plan. It profiles the most important conflicting issues arising in a landscape that is fragmented and spoiled in many ways by human impacts and that prohibits the natural mobility required by many species. An ecological network therefore requires crossroads between areas of settlement and would benefit from corridors erected between isolated natural habitats.

Life will become tougher for those species adapted to cooler habitats. Many species have moved back to patches that in the meantime are isolated. Moving northward is often no longer an option. Ranges are moving to higher altitudes but there is no way beyond once the mountain top has been reached.

Shifts in climate and range can, moreover, lead to problems when species of a community react in various ways to change.

What option does the Black Wheatear have? Finding sufficient food for its young has become difficult. Thus, this migratory bird that breeds in Germany has suffered a marked decline in population. Its most important food source is larvae which emerge earlier from year to year due to the rise in temperature. Since the Black Wheatear has only slightly adjusted its timing on its return from its winter quarters in Africa, its main food source is not available when it is needed most.

Shifts in ranges can also lead to similar problems: when insects and their host plants move northward at varying speed rates and into different regions, insects are then left without their host plants and plants lose their pollinators.

Interrelations of this kind affect species and their habitats in the same way as temperature does. Complex interaction occurs between a habitat and its climatic environment, and accessibility as well as the availability of all other components are necessary for the survival of a species (including food, pollination, minerals, water supply etc.). A habitat is embedded in a perpetual interplay of events involving all factors that on the contrary to predictions made by computer models can influence the actual range and the status of a species. In other words, rather than improve the situation it might deteriorate. The Federal Agency for Nature Conservation estimates that within the next decades Germany will lose up to 30 % of its native species - and states that this trend is caused by large-scale fragmented landscapes and the impact of climate change. These figures are particularly worrying if you consider the high number of species already threatened.

The survival of both native and newly arrived species depends on a combination of many factors. Either species are able to succeed in colonizing suitable habitats that entirely fulfill their preferences or they will have to adapt to the new circumstances. Adaptation, however, takes time. Climate change is pushing ahead at such a fast pace that there is hardly any time left for adaptation. Whether or not a suitable habitat is found depends on the diverse options within the complex web that Nature has created but which is spoiled by many human impacts.

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