Global and Regional Ecological Changes and Imbalances

Global Environmental Change and Ecological Imbalance

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The biosphere has entered a new geological epoch — the Anthropocene — defined by the fact that human activity has become the dominant force shaping Earth’s physical, chemical, and biological systems. We now live in a world where humans are having profound impacts on the global environment: climate is warming, species populations are declining, pollution is affecting ecosystems and human health, and human societies face new risks in terms of sea-level change, disease, food security, and climate extremes.

Ecological imbalance

Ecological imbalance refers to the disruption of the natural equilibrium between living and non-living elements of the environment. It has been realised by mankind that living and non-living elements in the environment keep interacting to maintain a mutual balance called ecological balance. Any large-scale deviation from this balance — driven by industrialisation, irrational resource use, deforestation, or pollution — constitutes an ecological imbalance.

Global environmental change science is a highly multidisciplinary effort, involving physical scientists who study climate, the oceans, the atmosphere, and geology, as well as biologists investigating physiology, evolution, and ecology (Vitousek, 1994). The drivers of global change operate across scales: from individual organism physiology to population dynamics, community structure, and whole-ecosystem functioning.

Three issues stand out as the most critical global ecological changes of our era: ozone layer depletion, global warming and climate change, and the loss of biodiversity. Together, these constitute an interlocking planetary crisis, each reinforcing the others through complex feedback.

Drivers of Global Ecological Change

The drivers of global environmental change can be grouped into four primary categories, all of which are fundamentally linked to human population growth and the scale of economic activity.

Human population and consumption

• Almost 8.1 billion people now live on Earth (2024). The rapid growth of the human population, especially over the last 300 years, is one of the most remarkable demographic trends in history. Demographers project that the world population will rise to 9 billion by 2050 and level off between 9–12 billion by the end of the century. Population growth and the increased demand for natural resources are major drivers of global environmental change.
• However, the relationship between population and environmental impact is not simple. Affluence (wealth per person) and social norms of consumption are equally important variables. The IPAT equation captures this:

Energy use and climate change

• Fossil fuels — oil, coal, and natural gas — dominate global energy consumption, accounting for 85% of all energy used worldwide. The rapid rise of fossil fuels is a relatively recent phenomenon, developing in the 19th century with the discovery of oil and the industrialisation of economies, and expanding rapidly in the 20th century with rising populations and affluence.
• Burning fossil fuels releases approximately 8.5 billion tons of carbon (as CO₂) into the atmosphere each year, causing greenhouse gas concentration to increase and Earth’s warming to strengthen. Since 1880, the average global air temperature has risen approximately 0.9–1.1°C. The top five CO₂-emitting countries/regions are China, the US, the EU, Russia, and India, which together account for two-thirds of global emissions.
• Climate models indicate that if fossil fuel burning continues at current rates, global temperatures may rise by as much as 4°C by 2100 (IPCC 2007). Precipitation changes are expected to increase rainfall in mid-to-high latitude regions but intensify droughts in subtropical regions — which includes large parts of the Indian subcontinent.

Land use changes

• Landscapes are changing worldwide as natural land covers — forests, grasslands, and deserts — are converted to human-dominated ecosystems including cities, agriculture, and forestry. Between 2000 and 2010, approximately 13 million hectares of land (an area the size of Greece) were converted each year to other land cover types (FAO, 2010).
• Land use changes affect the biosphere in several interconnected ways:
  • They reduce native habitat, making it increasingly difficult for species to survive.
  • Deforestation and agriculture remove native vegetation, diminishing carbon uptake by photosynthesis.
  • They hasten soil organic matter decomposition, leading to additional greenhouse gas release — almost 20% of global CO₂ (1.5–2 billion tons of carbon) is estimated to come from deforestation.
  • Conversion of forests to cropland fragments habitats, creating isolated population patches vulnerable to local extinction.

Pollution

Pollution is one of the principal by-products of economic development — encompassing products and waste materials harmful to human and ecological health. Its rise corresponds to the increased use of petroleum in the 20th century, as synthetic products including plastics, pesticides, solvents, and industrial chemicals became central to modern life.

Ozone Layer Depletion

• Earth’s atmosphere is divided into three principal regions: the troposphere (0–12 km), stratosphere (12–50 km), and mesosphere (50–80 km).
• The ozone layer, located in the stratosphere, acts as an efficient filter for harmful solar ultraviolet (UV-B) radiation. Any disturbance or depletion of this layer results in increased penetration of UV-B to the Earth’s surface, with dangerous consequences for living organisms.

Ozone hole

• In recent years, scientists have measured a seasonal thinning of the ozone layer primarily at the South Pole — a phenomenon called the ozone hole. This represents the most dramatic manifestation of ozone depletion and has been directly linked to the release of anthropogenic chlorine compounds into the stratosphere.

Causes of ozone depletion

Effects of ozone depletion

• Human health: Increased skin cancer (melanoma), cataracts, suppression of immune system, increased incidence of infectious diseases.
• Forests and grasslands: UV-B damages leaf chlorophyll and disrupts photosynthesis; reduces crop yields (soybean, rice, wheat).
• Marine ecosystems: UV-B penetrates surface waters, damaging phytoplankton (basis of all marine food chains) and disrupting larval stages of fish and shellfish.
• Materials degradation: UV-B accelerates degradation of plastics, paints, and building materials.

International response: Montreal Protocol and beyond

• Global awareness and concerted action by the international community have produced one of the most successful environmental agreements in history:
  • Vienna Convention (1985): Established the framework for protecting the ozone layer.
  • Montreal Protocol (1987, revised 1990s): The first universally ratified UN treaty — mandated a complete phase-out of CFCs and other ozone-depleting substances. Regarded as the most successful international environmental agreement.
  • Helsinki Declaration (1989): Countries committed to phasing out CFCs by 2000.
  • HCFCs as interim substitute: Hydro-chlorofluorocarbons are relatively less damaging than CFCs but are not completely ozone-safe; their use was approved on a temporary basis pending the development of safer alternatives (HFCs).
  • Kigali Amendment (2016): Extended the Montreal Protocol’s scope to phase down hydrofluorocarbons (HFCs), which are powerful greenhouse gases even though they don’t deplete ozone.

Global Warming and Climate Change

• Over the decades, it has been established that the Earth is progressively getting warmer.
• The key greenhouse gas causing global warming is carbon dioxide (CO₂). Chlorofluorocarbons (CFCs), though present in very small quantities, also contribute significantly. Other important greenhouse gases include methane (CH₄), nitrous oxide (N₂O), and water vapour.

The greenhouse effect — mechanism

• The greenhouse effect is a natural atmospheric process essential for life on Earth — without it, Earth’s average surface temperature would be about −18°C instead of the current +15°C.
• However, the enhanced greenhouse effect — caused by the increased concentration of greenhouse gases due to human activities — is disrupting the radiation balance of the atmosphere.

Effects on living beings

• The ecological consequences of global warming extend through every level of biological organisation:
  • Plant productivity — paradox: Increased CO₂ concentration may increase photosynthetic productivity, producing more organic matter. However, weeds may proliferate rapidly at the expense of useful plants, and insects and pests that feed on plants may also increase in number — disrupting agricultural systems.
  • Species distribution shifts: Species are migrating poleward and to higher altitudes. India is already observing upward migration of montane species in the Himalayas — a critical early warning sign.
  • Phenological disruption: Mismatches between flowering times, pollinator activity, and migrant bird arrivals — threatening food webs and agricultural productivity.
  • Coral bleaching: Ocean warming causes coral expulsion of symbiotic zooxanthellae — the trigger for coral bleaching and death. Lakshadweep and Gulf of Mannar reefs have experienced repeated bleaching events.
  • Sea level rise: Thermal expansion of ocean water + glacial/ice-cap melt is projected to raise sea levels 0.3–1.0 m by 2100, threatening coastal cities and low-lying islands.
  • Water cycle disruption: Increased rainfall in higher latitudes; intensified droughts in the subtropics — affecting agriculture, groundwater, and river systems globally.

Strategies to mitigate the greenhouse effect

• Increased fuel efficiency of power plants and vehicles — the single most cost-effective near-term intervention.
• Development and implementation of solar energy and non-fossil fuel alternatives (wind, nuclear, hydrogen).
• Halting deforestation — preventing the ~20% of global CO₂ emissions attributable to land-use change.
• Afforestation — supporting and undertaking tree-planting programmes as carbon sinks.
• Carbon trading and pricing — using market mechanisms to internalise the cost of carbon emissions.
• Reducing air pollution — many air pollutants also act as short-lived climate forcers (e.g. black carbon).

Loss of Biodiversity

• Biodiversity refers to the variety of life on Earth and its biological diversity. It encompasses genetic diversity, species diversity, and ecosystem diversity.
• As Walter G. Rosen (1986) first coined the term — and E.O. Wilson later popularised it — biodiversity is not merely a catalogue of species but the sum of all evolutionary adaptations that have produced the capacity of life to sustain itself.

Ecological function of biodiversity

• Biodiversity boosts ecosystem productivity where each species, no matter how small, plays an important role. It is in the combination of species that an ecosystem possesses the ability to prevent and recover from a variety of disasters.
• Diverse ecosystems are more resilient to disturbance, more productive over time, and more capable of providing ecosystem services than species-poor ones.

Drivers of biodiversity loss

• The IPBES Global Assessment (2019) identified five direct drivers of biodiversity loss, ranked by impact:

Impacts of Eco-imbalance

• The impacts of polluted environments and imbalanced ecosystems are pervasive, crossing the boundaries of ecology, human health, economics, and geopolitics.
• Environmental degradation affects mankind at a global scale regardless of any particular country, region, or race.

Effects on human health

• Polluted air, water, and land generate many harmful chemical and biological agents with negative impacts on human health. A wide range of communicable diseases are spread through environmentally contaminated vectors. The plagues of the Middle Ages illustrate how disease can spread through rats fed on contaminated human waste. The outbreak of SARS in 2003 demonstrated that no country is immune to environmentally transmitted diseases — a lesson confirmed again by COVID-19 (2019–2022), which emerged from disrupted wildlife-human interfaces.

Soil degradation

• The protection of soil against degradation is essential for sustaining productivity. Soil degradation arises from multiple causes:
  • Soil erosion: The washing or blowing away of surface soil — greatly increased when human activities destroy the protective cover of natural vegetation. Erosion is a global problem.
  • Acidification: Caused by acid rain and accumulation of water-soluble acidic compounds; directly reduces soil fertility.
  • Salinisation: Accumulation of water-soluble salts in the soil — primarily from over-irrigation without adequate drainage.
  • Waterlogging: Persistent saturation destroys soil structure and drives away aerobic soil fauna and microorganisms.
  • Chemical degradation: Leaching of nutrients; accumulation of persistent organic pollutants (DDT, PCBs) and radioactive substances.

Desertification

• Desertification is the process by which fertile land loses its productive capacity and becomes desert. Four categories of desert are recognised:
  1. Rainless deserts: rainfall is not an annually recurring event.
  2. Run-off deserts: annual rainfall below 100 mm — low and variable.
  3. Rainfall deserts: rainfall insufficient for crop production (100–200 mm).
  4. Man-made deserts: semi-arid areas (rainfall 200–350 mm) transformed by human over-exploitation of land.
• Desertification results from the combined effect of severe recurrent droughts and human over-exploitation of drylands — overgrazing, deforestation, excessive irrigation. Corrective measures are expensive, involving biological recovery of environmental conditions (natural or artificially induced). Considerable experience in combating desertification has been acquired by the US, Australia, and Israel.

Genetic resource depletion

• The genetic material contained in domesticated varieties of crop plants, trees, livestock, aquatic animals, and microorganisms is essential for breeding programmes that produce improvements in yield, nutritional quality, disease resistance, and other traits.
• Because of intensive selection for high performance and uniformity in modern agriculture, the genetic base of food production has grown dangerously narrow.
• Entire crop varieties and their wild relatives are disappearing before they can be characterised or used — a process called genetic erosion.

Contamination of food

• Chemical contaminants reach food and livestock feed from multiple sources: pesticides used in farming find their way into crops; veterinary drugs and growth-promoting chemicals pass into meat and dairy products; food preservatives (sodium nitrite), packaging chemicals, and industrial effluents may contaminate food.
• Centralisation of food processing and large storage facilities amplifies these risks. Crops may be chemically contaminated by airborne deposition of industrial emissions or industrial effluents.

Ecological Imbalance in India

India’s ecological imbalance is driven by five interconnected factors, all operating simultaneously and reinforcing each other.

1. Degradation of land and soil erosion

• Heavy population pressure has led to the conversion of forest and permanent pastures into croplands, indiscriminate grazing, and removal of protective vegetation.
• Of India’s 329 million hectares of total land area, about 174 million hectares (53%) face serious degradation. Soil erosion through water and wind affects 144 million hectares.
• The Universal Soil Loss Equation (A = R.K.L.S.C.P — Smith and Wischmeier, 1962) provides the quantitative framework for understanding this erosion.

2. Deforestation

• Large-scale deforestation has continued since independence due to over-exploitation and mismanagement of forest resources.
• During 1951–1972, India lost about 3.4 million hectares of forestland, ~70% of which was lost to river valley projects, roads, communications, and industries.
• The degree of deforestation in the Himalayan ranges — from Kashmir to Northeast India — is very high, leading to ecological collapse, accelerated erosion, and loss of biodiversity.

3. Faulty utilisation of water resources

• India is one of the wettest countries in the world yet suffers from both floods and droughts due to faulty utilisation of water resources. Since independence, excessive emphasis was placed on large dams. These have displaced crores of tribal people, submerged millions of hectares of rich forest, failed to prevent floods, and often created destructive flash floods in downstream valleys.
• The area affected by floods in India has increased from 20 million hectares in 1971 to 40 million hectares at present. Large dams and multi-purpose projects have also degraded soil in command areas through waterlogging and increased soil salinity — primarily affecting the Indo-Gangetic plains of UP, Punjab, and Haryana.

4. Environmental problems from faulty mining practices

• Large-scale mineral extraction is creating serious environmental problems — ruining land, water, forests, and air.
• Impacts include: conversion of agricultural and forest land into mine stockyards, townships, roads, and railway lines; removal of vegetation and topsoil; air pollution from mineral dust; water pollution as rainwater flowing through mineral waste enters rivers and streams; land subsidence from underground mines; large-scale deforestation and soil erosion; and respiratory health hazards for mining communities.
• India’s New Mineral Policy (1993) attempted to check this pollution and mandate reclamation measures.

5. Industrial and atmospheric pollution

• Unplanned and uncontrolled growth of industries and poorly maintained automobiles create enormous atmospheric pollution.
• Main pollutants include CO₂, CO, oxides of nitrogen, SO₂, hydrocarbons, and metallic traces. Specific industrial pollutants include: lead from automobile emissions, urea dust from fertiliser factories, cement and lime dust from cement factories, and increasing radiation from nuclear power stations. Industrial wastes from fertiliser factories, paper mills, and leather factories are constantly discharged into rivers, lakes, and seas.

Current Affairs

• IPCC AR6 synthesis report (2023) — key findings
  • The IPCC’s Sixth Assessment Report confirmed that global surface temperature is already 1.1°C above the 1850–1900 baseline. Every increment of warming matters: at 1.5°C, 14% of the global population faces severe heat waves every 5 years; at 2°C, this rises to 37%. Approximately 3.3–3.6 billion people live in contexts highly vulnerable to climate change — predominantly in South Asia, Sub-Saharan Africa, and small island states. India’s vulnerability is particularly acute due to its dependence on monsoon rainfall, vast agricultural sector, and densely populated coastal zones.
• COP 28, Dubai (2023) — global stocktake
  • The first Global Stocktake under the Paris Agreement at COP 28 concluded that current national policies would lead to a temperature rise of 2.5–3°C by 2100 — well above the 1.5°C target. The outcome document called for the first time for a “transition away from fossil fuels in energy systems.” India, while supporting the fossil fuel transition language, insisted on the right to development and equity in the burden-sharing of climate action. The UAE Consensus also affirmed tripling global renewable energy capacity and doubling energy efficiency by 2030.
• IPBES Nexus Assessment (2024)
  • The IPBES released its landmark Nexus Assessment in 2024, examining the interconnections between biodiversity, water, food, health, and climate. The key finding: the five drivers of biodiversity loss (land-use change, exploitation, climate change, pollution, invasive species) operate simultaneously and amplify each other. Addressing any one in isolation while ignoring the others will fail. The assessment projected that business-as-usual could result in up to 54% of species facing extinction risk by 2100 in the most affected regions.
• India’s heat wave crisis (2023–24)
  • India experienced its most intense and prolonged heat wave season in recorded history in 2024, with temperatures exceeding 50°C in parts of Rajasthan. The India Meteorological Department confirmed that the frequency, duration, and intensity of heat waves have increased significantly since the 1980s — consistent with IPCC projections for a +1.1°C world. Urban heat islands in Delhi, Hyderabad, and Nagpur amplify base warming by 3–5°C, demonstrating the human ecology dimension of climate change.
• Namami Gange — progress report 2024
  • The National Mission for Clean Ganga (2014–ongoing) has constructed 187 Sewage Treatment Plants with a total capacity of 6,207 MLD as of 2024. Water quality monitoring shows improvement in dissolved oxygen levels in several stretches. However, the Central Pollution Control Board (CPCB) continues to flag the Kanpur, Varanasi, and Kolkata stretches as critically polluted — demonstrating that river restoration requires simultaneous action on industrial discharge, agricultural runoff, and solid waste management.
• India’s forest fire crisis (2024)
  • The Forest Survey of India recorded over 36,000 forest fire incidents in 2024 — a 30% increase over the five-year average. Uttarakhand, Odisha, and Manipur were most severely affected. Forest fires release stored carbon, destroy biodiversity, trigger soil erosion, and disrupt water cycles — making them a direct manifestation of the intersection of deforestation, climate change, and ecological imbalance analysed in this article.