The climate crisis is the focus of attention worldwide, while a second equally threatening crisis usually gets less attention: the rapid loss of biodiversity. But as scientists are now emphasizing, both crises are closely linked – and therefore also require coordinated action. Because without climate protection, biodiversity will continue to decline, while the lack of species protection reduces nature’s buffering effect and increases climate change.
We humans have greatly changed our planet and also interfered with the balance of energy and material flows on Earth. The result is global climate change, as a result of which the atmosphere and the Earth’s surface continue to warm, and the distribution of precipitation shifts and extreme weather events increases. Ocean sea levels rise, waters become more acidic, and hypoxic zones spread. “The climate crisis that he himself caused is perhaps the greatest challenge that Homo sapiens had to face in its 300,000-year history,” says Hans-Otto Pörtner of the Alfred Wegener Institute, Helmholtz Center for Polar and Marine Research.
Two crises in close interaction
But this is not the only man-made crisis on our planet: “At the same time, a second equally serious crisis is occurring, which often happens – a catastrophic loss of animal and plant species throughout the planet,” Fortner says. In a public study, he and his team presented impressive numbers about the ongoing loss of the species. Accordingly, we humans have already altered about 75 percent of the Earth’s surface and 66 percent of the ocean areas. Habitat loss and destruction of natural ecosystems, in turn, has reduced the biomass of land mammals by about 80 percent and plants by half. More species are threatened with extinction today than at any time in human history.
In addition, this biodiversity crisis has been exacerbated by climate change. “Both catastrophes – the climate crisis and the biodiversity crisis – are mutually causing and mutually reinforcing, and therefore should in no way be viewed in isolation,” explains Pfortner. On the other hand, climate change deprives many species of their livelihood: they have to follow the shift in climatic zones in order to maintain the living conditions they need. However, many species are not mobile or adaptable enough – they are caught in a temperature trap: tropical corals, high mountain species or polar species have no alternative and they die. At the same time, warming also reduces the carbon storage capacities of organisms and soils, which in turn exacerbates the climate crisis.
It is possible only with coordinated action
According to Fortner and his international team, the vicious cycle that encompassed both crises can only be broken if coordinated measures focus on protecting the climate and species. Then there are significant synergistic effects: “Extensive re-saturation of only 15 percent of areas converted to farmland could be sufficient to prevent 60 percent of extinction events that are still expected,” explains the researcher. “At the same time, up to 300 gigatonnes of carbon dioxide could be removed from the atmosphere and bound in the long term, which is equivalent to 12 percent of the total carbon emitted since the beginning of the industrial age.”
In order to face the crises, the scientists propose a package of measures consisting of emission reduction, re-saturation, protection measures and sustainable usable land management. In addition to complying with the 1.5-degree target, they call for at least 30 percent of the Earth’s surface to be placed under protection or reconfigured in order to avoid the greatest loss of biodiversity and to preserve the functions of natural ecosystems. Nature reserves should not be isolated islands, but should be transformed into a global network of migration corridors. In areas that we humans use intensively for farming or fishing, it is imperative to find new resource-conserving forms of use that also increase carbon sequestration in biomass and soils.
“However, all of this only works if climate protection, biodiversity conservation and social benefits for the local population are considered together in all the measures decided upon,” says Pörtner. “New global biodiversity, climate and sustainability targets planned for 2030 and 2050 are likely to fail if individual institutions do not work together interdisciplinaryly.” the climate. “We desperately need a comprehensive approach here if we are to achieve the goals,” Pfortner said.
Source: Alfred Wegener Institute, Helmholtz Center for Polar and Marine Research; Specialized article: Science, doi: 10.1126/science.abl4881
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