The quality of the natural world around us affects human health every day, often in ways that go unrecognised. Food, water, air, and the built environment all influence physical and mental well-being, and the discipline of environmental health exists to study those connections and find ways to reduce harm. With the global population growing rapidly and resource exploitation at historic levels, experts warn that many of the resulting health burdens are preventable — but only if action is taken.
Air pollution stands out as one of the most widespread threats. The World Health Organization estimates that nine out of ten people worldwide breathe polluted air, contributing to nearly nine million deaths each year. Among the most vulnerable are children: WHO figures show that 600,000 die annually from respiratory infections linked to air pollution. Water contamination compounds the problem. Around 780 million people lack access to safe drinking water, and approximately 2.5 billion — close to one-third of the world’s population — have no access to adequate sanitation. More than 2,000 children die every day from diseases connected to unsafe water and sanitation conditions.
Toxic substances and hazardous waste present a further layer of risk. Global chemical production grew from roughly one million tons per year in 1930 to around 400 million tons by 2000, and the pace has not slowed. WHO links exposure to man-made chemicals to more than 1.6 million deaths annually, with the average person absorbing approximately 300 such substances.
Climate change adds another dimension: rising temperatures and increasingly extreme weather events — droughts, wildfires, hurricanes, and heatwaves — threaten communities and infrastructure worldwide. A 2019 European Environment Agency report found that heatwaves are already the deadliest category of extreme weather in Europe, and projects that annual deaths from heatwaves on the continent could exceed 130,000 under current warming trajectories. Across all environmental factors, research suggests that 23 percent of global deaths — and 26 percent of deaths among children under five — are attributable to preventable environmental health problems.
The underlying message from researchers and public health bodies is consistent: environmental degradation is not a separate concern from human health — it is central to it
A range of practical measures can help reverse these trends. Experts and advocates point to expanding tree cover to absorb carbon dioxide, reducing plastic use — which currently accounts for 80 percent of marine pollution — and shifting toward regenerative agriculture, which can cut emissions and restore degraded soils. On the energy side, switching to efficient lighting can reduce household electricity consumption by between 25 and 80 percent, while electric vehicles can cut a car’s carbon footprint by up to 70 percent compared with petrol-powered alternatives. Rainwater harvesting offers a low-cost way to ease pressure on freshwater supplies and reduce runoff and erosion.
The underlying message from researchers and public health bodies is consistent: environmental degradation is not a separate concern from human health — it is central to it. Many of the deaths and illnesses linked to environmental factors are avoidable, and the tools to address them, from policy changes to individual choices, already exist.