The stocks of wild vertebrates have shrunk massively in the past 50 years. Between 1970 and 2018, an average of 69 percent had to be observed in the more than 31,000 populations examined, the environmental foundation WWF and the Zoological Society of London wrote in its now published »Living Planet Report 2022«. Overall, the data for more than 5230 vertebrate species around the world was evaluated. This includes mammals, birds, fish, amphibians and reptiles.
The causes of the declining populations and the loss of species are basically known: wildlife habitats are being lost through deforestation and land development; pollution and climate change have an additional impact on habitats.
According to the report, the animal species in fresh waters are particularly affected. They have decreased by an average of 83 percent; the population of the Amazon dolphin in Brazil, for example, has decreased by around 65 percent from 1994 to 2016. Among the land animal species, the situation of the Western Lowland gorillas, for example, is of concern. Their population in the Nki National Park in Cameroon has shrunk by around 69 percent between 2005 and 2019 alone. But species native to Europe are also affected: for example, the population of skylarks has decreased by about 56 percent from 1980 to 2019.
Interaction between loss of species and climate change
The authors of the report warn of a "fatal interaction" between species extinction and the climate crisis. According to the Intergovernmental Panel on Climate Change (IPCC), the impact of the climate crisis on biodiversity will increase dramatically by 2100. As the WWF estimates in a press release, with global warming of 1.5 degrees Celsius, the proportion of species that would become extinct at high risk is 4 percent. If warming increases by 3 degrees, this share could amount to 26 percent.
At the same time, the decline in animal population would fuel climate change because the ecosystems could absorb less carbon. The connection between the African forest elephants can be observed particularly well, the WWF writes. Its stocks have already declined by more than 90 percent in some areas. And without forest elephants, the composition of the forest changes so that it can save less carbon.
But there are also a few successes to report, which go back to efforts in nature conservation, according to the WWF. The populations of grey seals in the Baltic Sea, for example, recovered between 2013 and 2019: they grew by 139 percent. The tiger population in Nepal also grew by 91 percent from 2009 to 2018.
