-L’impact du changement climatique sur la biodiversité

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effet biodiversité changement climatiques animaux disparition

Plants and animals were already sensing the first signs of climate change before human beings were aware of its existence. Spring came earlier, bringing forward the moment when the buds burst, and milder conditions made it possible for a number of species to inhabit areas previously ill suited to their needs. The living world found itself changed in terms of both time and space.

In the face of global warming, living creatures seek out cooler zones, moving towards the poles or upwards, to higher altitudes. The range of a great many species will likely shift. But there are geographical limits to such migration: no species can keep climbing upwards or migrating towards the poles. Sometimes, there is simply nowhere left to go.

This is the case for the polar bear. With the ice floes melting earlier each year, the animal’s hunting period is getting shorter and shorter. The result is that the bear cannot replenish its fat reserves before the winter and females find it increasingly difficult to feed their young. With the melting of the Arctic ice, the polar bear will eventually die out. And it is not alone: coral reefs bleach and eventually die when the temperature increases and humid tropical forests become too dry. Over forty years, an increase of just 5.4°F (3°C) would mean extinction for 30% of all living species.

And humanity could suffer direct consequences too: higher temperatures, for example, encourage swarms of insects that carry disease. This was the case with the tropical mosquitoes that appeared in the USA in 1999, carrying the potentially fatal West Nile fever. Dengue fever and malaria, other mosquito-borne diseases, could infect hundreds of millions of additional victims.

So what should we do? Animals are capable of learning and adapting, but only over generations. The current temperature increases are happening too fast. There is no one particular solution, other than redoubling our efforts to protect the living world, since the better the health of the planet’s ecosystems, the better they will be able to tolerate climate disturbances. One possible way forward is to combat the fragmentation of ecosystems by creating contiguous protected zones, or “ecological corridors” between zones, so that animals can migrate towards areas better suited to their needs.

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