Global environmental changes, both positive and negative, have been documented for decades. Examples include climate change and pollution of air, water, soil, and food sources. While some of these hazards are localized and easily remediable, others are largely irreversible.

Since the mid-20th century, human activities, mainly burning fossil fuels such as oil and coal, have increased atmospheric concentrations of greenhouse gases like carbon dioxide (CO2). This has resulted in an increase in global average temperature over that timeframe.

Climate change has had a devastating impact on ecosystems and the biodiversity they support, leading to an increase in extreme weather events such as heat waves and hurricanes; altered growing seasons, length of winters, rainfall patterns; flooding, drought, wildfire; changes to ocean currents, saltwater intrusion into freshwater inputs; enhanced ocean acidification; and rising sea level.

The effects of long-term changes on ecosystems vary by region due to the intricate interactions between organisms and disturbance. Nonetheless, some ecosystems appear to have adjusted well to these changes.

Some species are expanding their geographic ranges or blooming earlier than before, while some plants are flourishing in new locations due to increased sunlight exposure. Unfortunately, in many ecosystems, anthropogenic warming and other climate change-related stresses are wreaking more havoc than good.

However, it is essential to remember that these impacts are just the tip of the iceberg. Other human activities such as land use and forestry practices, pollution, and the introduction of invasive species have an extensive negative effect on both natural environments and local communities.

Health professionals must grasp the full scope of environmental determinants and their effects on population health in order to effectively address these concerns. This is no small feat.

In addition to direct impacts on human health, global environmental change also has an effect on society at large. Therefore, it is necessary to consider how this affects prevention strategies and the development of healthcare systems across different countries.

Understanding the socioeconomic causes of environmental pressures, and their regional effects, are essential in understanding how environmental hazards will affect population health in the long term. If these risks aren’t addressed now, they will persist into the future and disproportionately impact those most at risk around the world.

As an example, COVID-19 has led to positive changes in pressures around the world by 2025, such as reduced emissions of GHGs, decreased materials use, and lower levels of other pollutants like nitrogen oxides (NOx) and sulfur dioxides (SO2). For India specifically, these declines were greater than reductions in GDP growth.

Additionally, there is evidence to support the connection between reducing environmental pressures and increased life expectancies. Globally, up to 25% of disease burden–including many leading causes of death–can be attributed to modifiable factors in air, water, and soil. Unfortunately, these adverse health effects are particularly acute for lower-income countries that are often more exposed to such hazards.