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Human population boom will increase contact with wild animals
Humanity is increasingly coming in contact with wild animals.
As human populations grow, more and more land will be shared between people and wildlife. By 2070, this overlap will have grown across more than half of the world’s land surface, forcing us to develop new approaches to our relationship with nature.
It’s a small world – and we’re needing to share more and more of it.
The global population passed eight billion in 2022, and is set to rise by another two billion over the next 60 years. Demand for space is therefore on the rise, and as humans move into new areas they’re more likely than ever to come into contact with wild animals.
New research, published in the journal Science Advances, suggests that this situation will become much more common by 2070. It predicts that the overlap between humans and wildlife will grow across 57% of the world, and decline across only 12%.
As demand for space rises, it will become increasingly difficult to set aside unpopulated land as protected areas. Instead, as the study’s co-author Dr Neil Carter explains, it will mean changing how conservation is done.
“Our study suggests that with more areas of the world expected to be shared both by people and wildlife, conservation planning will have to get more creative and inclusive,” he says. “In some places it’s going to be really hard to do everything at once: to grow crops and have urban areas and protect these species and their habitats.”
“But if we can start planning now, then we have a lot of tools to help us promote sustainable coexistence.”
An area of African rainforest the size of China will have more encounters between wildlife and humans by 2070. © Roger de la Harpe/ Shutterstock
Biodiversity under pressure
It’s thought that around half of land on Earth is used directly or indirectly by humans, be that for housing, food production, resource extraction or otherwise. This area is only going to grow in the coming years, with some estimating that it could rise to 70% by the 2060s.
As the area of land used by humans grows, it’s inevitable that people and wildlife will end up sharing more of the same space. It’s also something that’s likely to be exacerbated by climate change, which will cause many species to alter where they live as they adjust to rising temperatures.
“In many places around the world, more people will interact with wildlife in the coming decades and often those wildlife communities will comprise different kinds of animals than the ones that live there now,” Neil says. “This means that all sorts of novel interactions, good and bad, between people and wildlife will emerge in the near future.”
Finding out exactly which species humans will be running into, and where, is vital to plan for the future. New encounters between humans and wildlife can raise the risk of new diseases spreading, or might bring venomous snakes or big cats closer to urban areas.
To try and get an idea of where this overlap might occur, the researchers used existing research to predict where over 22,000 species of amphibians, birds, mammals and reptiles might live in the year 2070, and compared it to forecasts of where humans will be living.
They found that in over half of the world’s lands, the overlap between humans and wildlife will double by 2070. Dr Deqiang Ma, the lead author of the study, explains that this is mostly being driven by the changing number of humans, rather than wildlife.
“We found that changes in human-wildlife overlap are mainly driven by changes in human population density, as the magnitude of these changes is greater than that of changes in species richness,” Deqiang says. “This increasing overlap is the result of the expansion of human population much more so than changes in species distributions caused by climate change.”
Humans will need to share more of the world with wildlife to ensure that vital ecosystem services continue. © Sourabh Bharti/ Shutterstock
Of concern is that these crossovers increase most in the biodiverse continents of Africa and South America, where the overlap between humans and wildlife is currently relatively low. It’s set to rise across two-thirds of the continents by 2070, especially in species-rich forests.
In response, the animals living in these areas are predicted to decline. For example, in the forests of South America the average number of reptile and amphibian species are set to decrease by over 40%. Meanwhile, in Africa’s woodlands bird and mammal species richness is predicted to fall by around a fifth.
As this overlap grows in biodiversity hotspots, it will be more important than ever to protect these habitats for the benefit of both people and wildlife. Conserving areas of mangroves inside urban environments, for example, can give young fish a shelter while protecting houses from flooding.
Other potential steps could include temporarily closing off certain areas during important times of the year, such as an animal’s breeding season, and providing more wildlife corridors to link up protected areas.
At the same time, humanity will need to get used to having animals once seen as ‘undesirable’, like hyaenas, living alongside them.
“Hyenas and other scavengers, like vultures, are often vilified or persecuted because they’re seen as a threat,” Neil says. “But they provide a lot of benefits, like removing waste and clearing an area of carcasses, that reduce the risk of the disease.”
Engagement between conservationists, local communities and Indigenous Peoples will become more important than ever as the world becomes busier. Being flexible to the needs of wildlife and people is crucial to ensure that both can be given the opportunity to thrive in the twenty-first century.
