Environmental Challenges: Pollution, Climate Change & Biodiversity Loss
Water Pollution
Industrial discharge, urban runoff, agricultural practices, and livestock are the main pollutants of freshwater sources, both surface and subterranean. Millions of tonnes of waste accumulate, impacting these vital resources.
- Agricultural areas contribute to pollution through ammonia and nitrate derivatives, fertilizer residues, and pesticides.
- Industries can release heavy metals and organochlorines, which are difficult to degrade and accumulate in living organisms, leading to biological magnification. The worst affected areas are often the final sections of rivers, deltas, estuaries, and marshes – biologically sensitive habitats.
Soil Degradation
Soil, the layer of variable thickness on the Earth’s surface, is formed from bedrock by the action of climate and living organisms. It’s composed of mineral particles, organic matter, water, air, and living organisms like fungi and microorganisms. Soil is the substratum of plants, providing them with water and essential nutrients. However, it’s a resource that’s difficult to renew and faces numerous threats:
- Erosion
- Loss of organic matter
- Contamination
- Salinization
- Compaction
- Loss of biodiversity
- Landslides
- Floods
Forests and wetlands are particularly vulnerable to soil degradation.
Biodiversity Loss
Biodiversity encompasses all hereditary variation in the world, from the genetic level to individuals, populations, species, communities, and ecosystems. It’s estimated that between 50-98% of species remain unknown, with only 2 million currently identified and 300,000 known from fossils. Biodiversity is crucial for numerous reasons:
- Purifying air and water
- Maintaining soil fertility
- Enabling evolution and adaptation
- Providing food and medicine
Threats to biodiversity include:
- Habitat disturbance
- Introduction of invasive species
- Overexploitation
- Contamination
- Climate change
It’s predicted that in the next 30 years, we could lose 20% of existing species.
Development and Sustainability
Development often equates to better living standards, access to goods and services, and improved healthcare. However, this typically involves increased resource consumption, leading to waste, pollution, and climate change. Sustainable development requires a balanced approach:
- Economic: Economic development should benefit society as a whole.
- Social: Economic development must positively impact every human being.
- Environmental: Development must not exceed the planet’s carrying capacity.
There are different perspectives on development:
- Developmentalist Model: Focuses on consumerism and relies on technological solutions without addressing fundamental changes in lifestyle.
- Conservationist Model: Advocates for halting economic development and population growth, emphasizing the finite nature of resources and the need for radical lifestyle changes.
- Sustainable Model: Proposes economic growth that doesn’t increase resource demand.
Climate Change
Climate change has both natural causes (solar activity, volcanic eruptions, changes in gas concentrations) and human-induced causes. The current rapid change is primarily driven by human activities, particularly the burning of fossil fuels, which release large amounts of carbon dioxide and nitrogen oxides into the atmosphere. Consequences of climate change include:
- Sea level rise (due to melting ice), impacting islands and coastal areas, leading to the potential disappearance of crop areas and densely populated regions.
- Changes in rainfall patterns, affecting aquifers and rivers.
- Shifts in vegetation and fauna distribution, altering migration patterns.
- Expansion of deserts.
- More frequent and intense weather events.
The economic, social, and biological consequences of climate change are unpredictable and potentially devastating.
Ozone Layer Depletion
The ozone layer protects life on Earth from harmful ultraviolet radiation. Human activities have led to the depletion of this vital layer, increasing the risk of skin cancer and other health problems.
Environmental Impact and Pollution
Environmental impact refers to any change in the environment, including the landscape and ecosystem health, caused by human actions.
Pollution is the introduction of harmful substances or forms of energy (heat, noise, light) into the environment at levels that exceed its capacity to absorb them.
Air Pollution
The primary source of air pollution is the burning of fossil fuels, releasing carbon oxides, nitrogen and sulfur oxides (leading to acid rain), particulates, and hydrocarbons. Livestock, agriculture, and the decomposition of organic matter also contribute to air pollution through methane and other emissions.
- Smog: Smoke, particles, sulfur, and soot from coal combustion, often blanketing cities and reducing visibility.
- Photochemical Smog: A dark orange haze formed from nitrogen oxides and other compounds reacting with oxygen in the presence of ultraviolet light, creating ozone, formaldehyde, and ketones.
Water Contamination
Contaminated water is unfit for consumption and can result from natural or human causes. There are different types of water contamination:
- Physical: Heat, suspended solids, particles, and radioactive materials.
- Chemical: Biodegradable and non-biodegradable substances.
- Biological: Viruses and bacteria.
Pollution of rivers and lakes can destroy their ecosystems.
Eutrophication: Caused by excessive nutrient concentrations in an ecosystem, leading to algal blooms and oxygen depletion.