Biodiversity, simply defined as the variety of all living things on Earth, extends from the genetic differences within a species to the vast array of ecosystems across the planet. This intricate web of life provides essential resources and services that underpin human existence. A healthy planet with diverse life forms is intrinsically linked to human well-being. The ongoing loss of biodiversity, therefore, poses significant and multifaceted threats to human health, impacting everything from disease regulation to the availability of food and medicine.
Biodiversity and Disease Regulation
Diverse ecosystems can act as natural defenses against the emergence and spread of diseases. A concept known as the “dilution effect” suggests that in a biodiverse environment, a greater variety of host species can reduce the prevalence of pathogens in any single host, thereby lowering the risk of disease transmission to humans.
However, biodiversity loss can disrupt this natural balance, making human populations more vulnerable to infectious diseases. When habitats are encroached upon or degraded, it can increase contact between humans, livestock, and wildlife, facilitating the spillover of pathogens. Additionally, biodiversity loss often favors “generalist” species, such as certain rodents or mosquitoes, which are more adaptable to disturbed environments and are often more likely to carry and transmit pathogens that can jump to humans. Many emerging infectious diseases, including HIV/AIDS, Ebola, and COVID-19, are zoonotic, often linked to such ecological disruptions.
Impact on Food and Nutrition Security
The decline in biodiversity directly threatens the stability and diversity of global food supplies. Genetic diversity within crops and livestock is important for building resilience against pests, diseases, and the impacts of climate change. Relying on a narrow range of species or varieties makes agricultural systems more susceptible to widespread failures if a new disease or environmental challenge emerges.
Pollinators, such as bees and butterflies, are another example of biodiversity’s direct link to food security. Approximately 75% of global food crops and 35% of flowering plants depend on animal pollination for successful growth and maximum productivity. A significant decline in pollinator populations can lead to reduced yields for many fruits, vegetables, and nuts, impacting both the quantity and nutritional quality of available food. This reduction in food diversity can contribute to nutritional deficiencies and weaken dietary resilience. Marine biodiversity also plays a role in human nutrition, as diverse aquatic ecosystems provide a wider range of essential micronutrients.
Biodiversity as a Source of Medicine
Nature has historically served as a vast pharmacy, providing the basis for many existing medicines and offering potential for future drug discovery. A significant number of drugs, including common ones like aspirin (originally from willow bark) and penicillin (from mold), are derived from natural sources, including plants, animals, fungi, and microorganisms.
The ongoing loss of species means an irreversible loss of unique genetic material and biochemical compounds. The accelerated loss of species directly impacts the potential for new medical breakthroughs. For communities that rely on traditional medicine, which often uses natural remedies, biodiversity loss directly affects their access to healthcare.
Ecosystem Contributions to Human Health
Healthy, biodiverse ecosystems provide a range of services that are foundational to human health and well-being. These services include the purification of air and water, which directly impacts respiratory and overall health. Ecosystems also play a role in regulating climate patterns by absorbing carbon dioxide and mitigating extreme weather events, which can have indirect health benefits by reducing the incidence of heat-related conditions or injuries from natural disasters.
Maintaining healthy soils, supported by diverse microbial communities, is also important for food production. Beyond these physical benefits, exposure to nature and green spaces has been linked to mental health improvements, including stress reduction, improved mood, and enhanced cognitive function. The degradation of these ecosystem services due to biodiversity loss directly impacts both physical and psychological human well-being.