Population growth means that humans will push further into wildlife habitats across more than 50 per cent of land by 2070, according to a new study. Here we unpack how increasing overlap between humans and wildlife will lead to accelerating biodiversity loss, increased human-wildlife conflict, and worsening outcomes for local communities. We then examine the positive solutions available such as Population Health Environment (PHE).

No other species on earth has shaped the environment as much as humans, leading to a cascade of effects on other species.

Biodiversity, a measure of the diversity of species in an ecosystem, is being lost at an unprecedent rate, described by some as a Sixth Mass Extinction. Currently, the IUCN Red List has more than 45,300 species threatened with extinction, including 41 per cent of amphibians, 37 per cent of sharks and rays, 36 per cent of reef building corals, 26 per cent of mammals and 12 per cent of birds.

The main drivers of biodiversity loss are habitat destruction and overexploitation of species, driven by our growing numbers and the pressure of our unsustainable consumption on natural resources.

We’re using more land, more water, and producing more waste and pollution than ever before, with worsening effects for wildlife.

According to IPBES, only one-quarter of land areas and one-third of oceans remain relatively undamaged by human activity.

However, a new study published in Science Advances predicts that due to population growth, humans will push further into what remains of wildlife habitat. The study expects the overlap between human and wildlife populations to increase across 57 per cent of the Earth’s land by 2070, driven by human population growth.

More people, less space

As the global human population exceeds 8 billion people and affects up to 70% of terrestrial land area, humans and animals must share increasingly crowded landscapes.

Global expansion of human-wildlife overlap in the 21st century – Science Advances

The areas which are predicted to see the highest increase in human-wildlife overlap is in Africa and South America.

Sub-Saharan Africa has been identified as one of the fastest growing populations globally, currently at a population of 1.2 billion people that is expected to double to 2.5 billion by 2050.

However, in other regions with lower rates of population growth due to persistent low birth rates such as in Europe, the human-wildlife overlap was projected to reduce across 20 per cent of land.

As detailed in our Vanishing Icons report, rapidly growing populations contribute to biodiversity loss by three main factors:

• Habitat loss from land clearing. As local communities expand due to population growth, rates of deforestation increase as land is cleared to be cultivated into smallholder farms and settlements.
  
• Habitat fragmentation. A critical threat to many wild species is habitat fragmentation – not simply loss of habitat area but loss of continuous areas of habitat where animals can roam. The ability to roam, especially for large mammals such as elephants and tigers, is crucial for natural behaviours including foraging, hunting, and mating. However, land cleared for development, can lead to isolated “islands” of habitat where wildlife lack sufficient territory to sustain themselves.
  
• Bush meat trade. People kill wild animals for food, referred to as bushmeat, which is a common practice in Africa, where wild meat provides an important source of protein for many. Experts cite population growth as a key driver of the increasing rates of bushmeat consumption since, for many low-income communities, bushmeat is a necessity and serves as a nutritional ‘safety net’ where farmed meat is uncommon.

Human-wILDLIFE cONFLICT

Overlap between humans and wildlife in shared landscapes causes more human-wildlife conflict as humans compete over natural resources with wild animals.

In Sri Lanka, human-elephant conflict is on the rise. Elephants are mega-herbivores that need to consume 150kg of vegetation and 190 litres of water daily, to meet these needs requires a large foraging area. However, high rates of deforestation in Sri Lanka, as well as the increased development of roads, settlements, and expanding farms, has meant elephant habitats are shrinking, forcing them into closer proximity with people.

Elephants often become attracted to grains stored in village settlements, which leads them to raid crops in some of the most food-insecure communities. This can lead to casualties on both sides, due to aggressive behaviour from elephants and villagers creating deadly traps.

Last year, 176 people died in elephant encounters on the island, and 470 elephants were killed – more than double the number of elephant deaths in 2010.

Elephants and humans can cohabit peacefully as long as sufficient space and resources are provided for both species, which will not occur if rapid population growth continues.

RISK OF ZOONOTIC DISEASES

The study cites the importance of preventing more human-wildlife overlap due to the risk of zoonotic disease transfer. Zoonotic diseases are infectious diseases that can jump from wild animals to humans. Around 75 per cent of emerging diseases in humans are zoonotic and are of increasing concern to global health authorities – as highly infectious diseases such as Covid-19, mpox, avian flu and swine flu – all likely originated as zoonotic diseases.

As humans increasingly encroach upon wildlife habitat, with communities sharing water sources or consuming bush meat, this increases the risk of a zoonotic disease jumping the species barrier and causing another epidemic.

Reducing human-wildlife overlap is the best means to prevent zoonotic diseases, and addressing root causes, such as ending local population growth, can achieve this.

Population Health Enviornment SOlutions

PHE is a development approach that recognizes the complex links between people, their health and the natural resources upon which they depend. PHE projects focus on providing voluntary family planning information and services, biodiversity conservation, and sustainable natural resources management in a coordinated manner.

Rural, low-income, subsistence communities tend to border critical areas for biodiversity. People often refer to them as “last-mile” communities because they are the furthest and hardest to reach with medical services. This prevents them from accessing modern contraceptives or family planning information.

PHE projects provide a vital opportunity for conservation of critical areas for biodiversity, as well as providing local communities with an unmet need for reproductive health services.

PHE projects that provide local communities with choice-based family planning programs long-term reduces the local fertility rate and slows local population growth, reducing further human-wildlife overlap.

Projects such as Conservation Through Public Health have also successfully reduced human-wildlife conflict through community education and rangers’ programs.

You can help support PHE as a solution to solve the biodiversity crisis here.