Living things include plants and animals, as well as fungi and microorganisms found in the soil. They're part of a wide range of ecosystems that include the frozen Antarctic, tropical rainforests, the Sahara Desert, mangrove wetlands, the old-growth beech forests of Central Europe and diverse marine and coastal regions around the world.
These habitats provide humans with many things needed to live, such as water, food, clean air and medicine. Collectively, they're known as ecosystem services — and they also depend on the interplay of species diversity. If any individual element disappears, for example when a species goes extinct, these services provided by nature can, in the worst case, also vanish forever.
How does our life depend on nature?
Without algae or trees, there would be no oxygen. And without insects to pollinate plants, our harvests would be meager at best. More than two-thirds of all crops, including many fruits and vegetables, coffee and cocoa, depend on natural pollinators like insects. But already today, one-third of all insect species worldwide are threatened with extinction.
Although we owe our very existence to the services that nature provides, we usually take them for granted, said Dave Hole a climate change and biodiversity scientist at US-based Conservation International. An expert on ecological genetics, he has co-authored a new study that sheds light on the importance of ecosystem services.
"When we have a bowl of cereal in the morning, we're not thinking about how nature helped to pollinate the crops [that have] gone into making that cereal," Hole told DW. "We are often blind to what nature is doing for us on an everyday basis."
According to the study, up to 70% of the world's harvests are directly or indirectly dependent on intact polders and mangrove swamps, in part because they protect land used to grow food crops from flooding.
Biodiversity worldwide under extreme threat
The Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services — IPBES for short — estimates there are at least 8 million species worldwide, but has warned that up to 1 million could go extinct by 2030. Biodiversity loss has already reached an alarming rate: one species, on average, is vanishing every 10 minutes. According to researchers, we are in the midst of the world's sixth mass extinction.
In Germany alone, the number of winged insects fell by three-quarters between 2008 and 2017. Worldwide, the population of wild mammals has dropped by 82%, according to IPBES. It's even worse for freshwater plants and animals, which have declined by 83% over the past 50 years — in Central and South America, that figure is as high as 94%, according to the environmental group WWF.
And, according to Hole's observations, the rate of biodiversity loss is accelerating.
Humans are responsible for species extinction
Research backs this up: through agriculture, soil sealing, the clear-cutting of forests, overfishing, the introduction of toxins into nature and the spread of invasive species by humans, the extinction rate today is up to 100 times higher than it would be without human interference.
Can we save species from extinction?
Elizabeth Maruma Mrema, executive secretary of the UN Convention on Biological Diversity, is quite clear in her view that we are to blame. "Ninety-seven percent of the global biodiversity is degraded as a result of human action on that biodiversity," she told DW.
Her list of statistics is alarming: 75% of Earth's land area and 66% of the world's oceans are currently degraded, 85% of all wetlands are degraded or have already disappeared and half of all coral reefs have died off. And these figures don't even take into account how much of the planet is littered with plastic, Mrema added.
Biodiversity loss threatens future of humanity
"The advancing loss of our natural capital poses the greatest threat to all of humanity," said Klement Tockner, director general of the Senckenberg Society for Nature Research. "Once it's lost, it's lost forever."
The balance of nature doesn't collapse overnight when a species disappears from an ecosystem, but it does begin to change. "The more we reduce the number of species, the more susceptible a system becomes to disruption," said Andrea Perino of the German Center for Integrative Biodiversity Research Halle-Jena-Leipzig, in eastern Germany.
Ecosystems, like the climate, also have tipping points which can result in the radical and unstoppable transformation of our world, said Hole. One example is the Amazon rainforest. After the forest has been extensively cleared, the isolated pockets which remain find it increasingly difficult to recover. That, in turn, increases the risk that the entire rainforest will collapse.
And yet, tropical rainforests like the Amazon are home to around two-thirds of all known species worldwide — and are extremely important when it comes to regulating the global climate.
Protecting nature is in our own interest
Without a massive effort to halt the ongoing biodiversity collapse, the natural foundation of human life will be lost at an unprecedented rate — with long-term consequences for virtually all facets of life on Earth.
Half of all global economic output is directly dependent on nature, said Mrema of the UN Convention on Biological Diversity. "We are killing that biodiversity, [even though] our life, our economy and our health is dependent on it."