Class 12 Indian Economic Development Notes · CBSE

Meaning of Environment

Meaning of Environment — understand environment definition, biotic/abiotic elements, four functions, carrying capacity, and environmental crisis. CBSE Class 12 IED notes with global warming, ozone depletion, and Montreal Protocol.

Last updated: 1 Sep 2026

Notes

Meaning of Environment

Class 12 Indian Economic Development — Definition, functions, carrying capacity, environmental crisis, global warming, and ozone depletion

Environment Definition and Elements

Environment
Environment is defined as the total planetary inheritance and the totality of all resources. It is the sum total of external forces which surround us, including all the biotic and abiotic factors that influence each other.
Think of environment like the operating system of a computer — it provides the resources (inputs) and absorbs the waste (outputs). Just as a computer crashes when you overload its OS, the environment fails when we exceed its carrying capacity.

Elements of the Environment — click to reveal

Functions of the Environment

Carrying Capacity and Environmental Crisis

Carrying Capacity

The environment is able to perform its functions without interruption as long as demand on these functions is within its Carrying Capacity.

Carrying Capacity

The environment functions without interruption when demand stays within its limits.

Condition 1: Resource Extraction ≤ Regeneration

Resource extraction should remain below the rate of resource regeneration.

Condition 2: Waste ≤ Absorption

Generation of waste should remain within the absorption capacity of the environment.

Violation → Environmental Crisis

When these conditions are not fulfilled, the environment fails to perform its vital function.

Consequences

Environmental crisis leads to global warming, climate change, ozone depletion, etc.

Reasons for Environmental Crisis

Population explosion and industrial revolution have increased demand for environmental resources.

Opportunity Cost

Opportunity costs of negative environmental impacts are high: (i) Increased financial commitments due to global warming. (ii) Rise in health expenditure due to decline in air and water quality.

Reversal of Supply-Demand Relationship

Reversal of Supply-Demand Relationship
AspectIn the PastPresently
Demand vs SupplyDemand was much less than supply⭐ Demand is far in excess of supply — beyond the rate of regeneration
PollutionWithin absorptive capacity of environmentBeyond absorptive capacity — pollution has become critical
Resource ExtractionRate of extraction less than rate of regenerationRate of extraction exceeds regeneration rate
Population PressureLow population pressure on environmentPopulation explosion increased pressure tremendously
ResultEnvironmental problems did not ariseWaste generation and pollution have become critical

Global Warming

Global Warming
Global warming is the observed and projected increase in the average temperature of earth's atmosphere and oceans. During the past century, the atmospheric temperature has risen by 1.1°F (0.6°C) and the sea level has risen several inches.
The atmospheric concentrations of carbon dioxide and methane (CH₄) have increased by 41% and 160% respectively above pre-industrial levels since 1750.

Causes

Burning of Fossil Fuels
Deforestation ⭐
Methane from Animal Waste
Increased Cattle Production

Effects

Melting of Ice ⭐
Natural Disasters
Tropical Diseases
Effect on Animals
Effect on Seasons

Ozone Depletion and Montreal Protocol

Ozone Depletion
Ozone depletion refers to the destruction of ozone in the ozone layer due to the presence of chlorine from manmade chlorofluorocarbons (CFCs) and other forces.

Causes

CFC, used as cooling substances in AC and refrigerators
Aerosol propellants and Bromofluorocarbons (halons), used in fire extinguishers

Effects

UV radiation seems to be responsible for skin cancer
UV radiation lowers the production of phytoplankton
UV radiation can also influence the growth of terrestrial plants

Montreal Protocol

  1. Historical treaty designed by UN members to protect the ozone layer by phasing out CFCs
  2. All signing members agreed to freeze CFC consumption and production by 2013
  3. ⭐ India signed the Montreal Protocol along with its London Amendment on 17.09.1992
  4. Has significantly reduced the burden of CFCs in the stratosphere and helped in ozone recovery
'Paryavaran' means Environment and 'Mitra' means Friend — the time has arrived for us to become 'Paryavaran Mitra' (Friends of the Environment).

Key Takeaways

Key Takeaways

  • Environment is the sum total of all biotic (living) and abiotic (non-living) elements that influence each other.
  • Environment provides resources for production, assimilates waste, sustains life, and provides aesthetic services.
  • Carrying capacity is the limit within which environment can perform its functions — exceeding it leads to environmental crisis.
  • Population explosion, intensive resource extraction, affluent consumption, and pollution are the key reasons for environmental crisis.
  • The supply-demand relationship has reversed: demand now far exceeds the environment's ability to regenerate resources and absorb waste.
  • Global warming (rising temperature due to CO₂ and methane) and ozone depletion (CFCs destroying the ozone layer) are the two biggest global environmental threats.
  • India signed the Montreal Protocol on 17.09.1992 — every citizen must become a Paryavaran Mitra.