How Human Activities Impact Ecosystems

Deforestation refers to the permanent removal of trees and vegetation from forests, primarily for human use such as agriculture, mining, urban expansion, and infrastructure development. While forests are renewable resources, the current pace of deforestation far exceeds natural regrowth, resulting in severe damage to global ecosystems.

One major driver of deforestation is the conversion of forested areas into agricultural land. In tropical regions like the Amazon, vast areas are cleared for soy production and cattle grazing. This not only eliminates trees but also fragments habitats, leading to biodiversity loss. According to a study by Curtis et al. (2018), agriculture was responsible for over 80% of global deforestation between 2001 and 2015, with 27% attributed to commodity-driven deforestation (permanent conversion).

Forest ecosystems support an estimated 80% of terrestrial species. Once forests are cleared, endemic species often cannot adapt to the rapid change, pushing many toward extinction. Deforestation also disrupts carbon and water cycles. Trees act as carbon sinks, and their removal contributes significantly to global CO₂ emissions, thereby accelerating climate change.

In Southeast Asia, including the Philippines, forest loss is also tied to logging (both legal and illegal), palm oil expansion, and mining. This has direct effects such as increased flooding, soil erosion, and reduced access to forest-based livelihoods for Indigenous communities.

The consequences of deforestation are not just ecological—they’re social and economic. As ecosystems degrade, food systems are disrupted, fresh water sources diminish, and vulnerable populations face increased displacement.

Source: Curtis, P.G., Slay, C.M., Harris, N.L., Tyukavina, A., & Hansen, M.C. (2018). Classifying drivers of global forest loss. Science, 361(6407), 1108–1111.

Biodiversity—the diversity of life across species, genes, and ecosystems—is critical for ecosystem stability, resilience, and human well‑being. Sadly, human activities are driving an unprecedented global decline in biodiversity.

A study by Ripple et al. (2017) found that the world’s largest and smallest vertebrate species face especially high extinction risks. Their work analyzed population trends across thousands of species and underscored that activities like habitat destruction, pollution, overexploitation, invasive species, and climate change are pushing many toward collapse. (See PNAS, DOI below)

As species vanish, ecosystem functions suffer: pollination, clean water, soil fertility, and disease regulation weaken. In the Philippines, endangered species like the Philippine eagle, tarsiers, and coral ecosystems signal the urgent need for habitat protection and restoration. Community-led conservation initiatives have shown promise, combining scientific knowledge with local stewardship.

Source: Ripple, W.J., Wolf, C., Newsome, T.M., Hoffmann, M., Wirsing, A.J., & McCauley, D.J. (2017). Extinction risk is most acute for the world's largest and smallest vertebrates. Proceedings of the National Academy of Sciences, 114(40), 10678–10683. DOI:10.1073/pnas.1702078114

Outdoor air pollution—from vehicle emissions, coal and oil combustion, and industrial processes—is a major global health risk. Fine particulate matter (PM₂.₅) penetrates deep into the lungs and bloodstream, resulting in respiratory and cardiovascular diseases. According to the Global Burden of Disease Study, around 4.2 million premature deaths globally are linked to PM₂.₅ exposure annually.

Ecosystems are also harmed: sulfur dioxide and nitrogen oxides produce acid rain, which acidifies soil and water, harming forests and freshwater habitats. Ground-level ozone damages plant tissues and reduces crop yields.

Source: Cohen, A.J., et al. (2017). “Estimates and 25-year trends of the global burden of disease attributable to ambient air pollution.” The Lancet, 389(10082), 1907–1918. DOI:10.1016/S0140-6736(17)30505-6

Climate change is driven by rising greenhouse gas levels—primarily carbon dioxide (CO₂), methane (CH₄), and nitrous oxide (N₂O)—released from burning fossil fuels, deforestation, and agriculture. These gases trap heat in the atmosphere, raising global temperatures and disrupting weather patterns.

The consequences for ecosystems are profound. Melting glaciers, sea-level rise, more frequent storms, shifting rainfall patterns, and droughts threaten habitat stability and food systems. Many species cannot adapt or migrate faster than the climate shifts, leading to population decline and extinction.

Mark Urban's 2015 meta-analysis (published in Science) combined data from 131 studies. It found that current climate policies could endanger up to 1-in-6 species globally. This risk rises with temperature; at 2 °C of warming, extinction risk hits ~5 %, at 3 °C it reaches ~8.5 %, and at *4.3 °C* warming, up to **16 %** of species could be at risk. 1

Source: Urban, M.C. (2015). Accelerating extinction risk from climate change. Science, 348(6234), 571–573. DOI: 10.1126/science.aaa4984

Urbanization refers to the rapid growth of cities, converting natural landscapes into built environments—roads, buildings, pavements—and fragmenting habitats. As cities expand, ecological systems face serious threats.

A 2022 study by Simkin et al. in PNAS analyzed the global impact of urban expansion on over 30,000 species (mammals, birds, reptiles, amphibians). They showed that newly urbanized land between 2015 and 2050 could place more than 800 species at risk—especially those living in biodiversity hotspots and small ranges (e.g., tropical forests) 1.

Urban expansion disrupts ecosystems in multiple ways:

• Habitat loss and fragmentation: Wildlife corridors are broken, isolating populations and reducing genetic diversity.
• Heat island effect: Concrete surfaces retain heat, altering local climate and stressing wildlife.
• Increased runoff: Impermeable surfaces send polluted water into rivers and wetlands, endangering aquatic species.
• Species filtering: Only adaptable urban “generalist” species thrive, reducing overall biodiversity—this trend is supported by global bird-plant meta-analyses 2.

Importantly, compact and green urban planning can mitigate these impacts: designing wildlife corridors, preserving greenspaces, and controlling the expansion footprint help reduce biodiversity loss.

Source: Simkin, R., Seto, K.C., McDonald, R.I., Jetz, W. (2022). “Sprawling cities are rapidly encroaching on Earth’s biodiversity.” PNAS.

The world produces over 300 million tons of plastic annually, and much of it ends up in rivers, oceans, and soils. A 2023 open-access review in Environmental Science and Pollution Research highlights that microplastics—tiny pieces under 5 mm—are now omnipresent: found in marine waters, freshwater systems, soils, and even the air we breathe. These particles can travel long distances, accumulate in wildlife, and move through the food chain to humans. 1

Plastic pollution harms ecosystems both physically and chemically. Animals mistake plastics for food, leading to internal injuries, starvation, or vulnerability to predators. They also serve as surfaces for toxic chemicals and disease-causing microbes to accumulate. At the base of food chains, microplastics can impair the growth and reproduction of plankton and shellfish, disrupting entire marine systems. 2

Human exposure through seafood, drinking water, and air is increasingly documented. Though long-term health effects are still under study, concerns include inflammation, hormonal disruption, and developmental problems. 3

Tackling plastic pollution requires multi-level action:

• Reduce single-use plastics through bans and consumer choices.
• Improve waste systems and extend producer responsibility.
• Clean-up initiatives for rivers and coasts.
• Innovate materials, such as biodegradable alternatives.

These efforts are essential to protect ecosystems, wildlife, and public health.

Source: Pal et al. (2023). “Microplastics in aquatic systems: A global review…” Environmental Science and Pollution Research, open-access.

Energy underpins modern life—from lighting and heating to transportation and manufacturing. However, how we produce and use it has major environmental consequences.

Fossil fuels (coal, oil, and gas) still supply around 80% of the world's energy. Burning them releases large volumes of carbon dioxide (CO₂), a major driver of climate change. It also emits pollutants like sulfur dioxide (SO₂), nitrogen oxides (NOₓ), and particulate matter—causing acid rain, smog, and respiratory illnesses.

Renewable energy sources—such as solar, wind, hydro, and geothermal—are cleaner alternatives. According to the International Energy Agency’s World Energy Outlook 2020, renewables supplied nearly 30% of global electricity in 2020, with solar and wind growing fastest. It's a freely available report with full online access.

However, renewables still have environmental impacts. Hydropower dams can flood ecosystems and disrupt river systems; large solar and wind installations require land, which can affect wildlife habitats. Additionally, mining for materials used in solar panels, wind turbines, and batteries carries ecological and social costs.

That’s why a sustainable energy transition must include smart planning. This means locating clean energy projects away from ecologically sensitive areas, recycling components like panels and batteries, and integrating energy-efficiency and grid improvements.

Source: International Energy Agency (2020). World Energy Outlook 2020.

Freshwater makes up just 2.5% of Earth’s water—and less than 1% is accessible. However, human activity is putting extreme pressure on this limited resource.

A 2012 study in *PNAS* by Mekonnen & Hoekstra found that humanity uses nearly 9,087 km³ of water per year (1996–2005). Around 92% of this is for agriculture—mainly irrigation—and 15% is “gray water,” or polluted water discharged after use 1.

Agricultural expansion depletes rivers, wetlands, and aquifers, especially in water-stressed regions. Meanwhile, runoff from fertilizers and pesticides floods waterways with nitrogen and phosphorus, causing eutrophication—dead zones, harmful algal blooms, and loss of aquatic species.

Polluted water from factories and inadequate sanitation spreads microbes and toxins, posing major health risks in developing areas. Industrial chemicals and heavy metals accumulate in wildlife and humans, disrupting ecosystems and increasing disease risk.

Solutions Include:

• Efficient irrigation—like drip systems to reduce water waste.
• Better farming practices—nutrient management and buffer strips to prevent runoff.
• Wastewater treatment—upgrading infrastructure to eliminate industrial and domestic pollution.
• Protecting natural filters—wetlands and riparian buffers that clean water and recharge aquifers.
• Sustainable consumption—reducing food and water waste and choosing low‑impact foods.

Source: Mekonnen, M.M. & Hoekstra, A.Y. (2012). “The water footprint of humanity.” Proceedings of the National Academy of Sciences, 109(9), 3232–3237.

From polluted waters to vanishing forests, climate chaos to plastic-choked oceans—what we’ve explored here only scratches the surface. Human activities continue to reshape and, too often, degrade the ecosystems that sustain life on Earth. Whether it’s through rampant industrialization, overfishing, unsustainable agriculture, light and noise pollution, or even poorly planned urban sprawl—our footprint is everywhere.

The effects aren’t isolated—they ripple outward, disrupting natural balances, collapsing habitats, and even threatening our own health, safety, and food security. But just as we are the cause, we can also be the solution.

Every conscious choice we make—from what we consume, how we travel, to the policies we support—shapes the future. The ecosystem is not separate from us. We are part of it. And protecting it is not just an environmental duty—it is a moral, social, and survival imperative.

Let this site be a call to awareness, but more importantly, a call to action. The Earth is watching. And the future is listening.

Reference for further reading: IPBES Global Assessment Report on Biodiversity and Ecosystem Services (2019)