Key Concepts: Environment,
Ecology, Entropy, Climate
Change
Course: Nature, Ecology, & Society (SOCY2121)
Module 1: Envisioning Environmental Sociology
Sem V- Minor + OE
Environme
nt
1 Environment
• The specific surrounding or medium with which every living organism
interacts with, derives its sustenance & to which it is fully adapted.
• Environment includes everything external to an organism that affects it,
including physical as well as living factors. UNFCCC definition- “all external
conditions that affect an organism or other specified system during its
lifetime”.
• UN Glossary of Environment Statistics: “the totality of all the external
conditions affecting the life, development & survival of an organism”.
• Can also be defined as “the sum total of living non-living components;
influences & events surrounding an organism”.
• Environment is the interaction between organism & the nature.
• Every organism in nature interacts with its environment, influences it & in turn
is influenced by it.
1a Components of
Environment
Biotic Abiotic
(Living) (Non-living)
Plants Animals Humans Air Water Soil
1b Environment: Some important features
• Dynamic & changing- due to natural forces (weather, volcanic eruptions) &
human actions (urbanization, deforestation).
• Interdependent components: all elements (biotic & abiotic) are interlinked.
• Diversity: wide variety of ecosystems (forests, oceans, deserts) & species
(plants, animals, micro-organisms), contributing to biological diversity.
• Limited Resources & can be subject to degradation: resources like fossil
fuels, minerals, etc) are finite & can be depleted by overuse. Pollution, climate
change, & overexploitation can degrade environmental quality and disrupt
ecological balance.
• Adaptability: ecosystems & species can adapt to environmental changes over
time.
• Balance & Equilibrium: maintains balance (ecological equilibrium) through
natural cycles (like water, carbon cycles)
Ecology
2 Ecology
• Study of the totality or pattern of relationships between organisms & their
environment.
• Scientific study of the interactions between living organisms & with their
physical environment.
• It examines how organisms adapt to their surroundings, how ecosystems
function, & how energy & nutrients flow through the environment.
• Helps us to understand how life & the environment are interconnected & how
changes in one part of an ecosystem can affect the whole system.
• Ecosystem- functional unit consisting of living organisms, their non-living
environment & the interactions within & between them (UNFCCC).
Entropy
3 Entropy
• In physics/thermodynamics: thermodynamic property of matter related to the
amount of energy that can be transferred one system to others in the form of
work.
• Entropy relates to the second law of thermodynamics (measure of the disorder
or randomness in a system).
• Also refers to a measure of the disorder, randomness or uncertainty in a
physical system.
• Systems naturally evolve from order to disorder (e.g., melting of ice, mixing
of gases).
• The more disordered a system is, the higher its entropy.
Higher entropy = more unpredictability.
• In environment studies, it refers to the loss of energy availability in
ecosystems or increasing disorder due to environmental degradation.
• Also linked to the efficiency of energy transfer in food chains.
• Without energy input or maintenance, systems move toward higher entropy —
more randomness, & greater disorder.
3a Examples of entropy
• Everyday physical examples
Melting ice cube: orderly arrangement of water molecules in solid form
becomes more disordered in liquid form — entropy increases.
Perfume spreading in a room: perfume molecules move from a concentrated
point to spread evenly in the air — randomness increases.
Unclean room over time: a tidy room becomes messy without effort —easier
for systems to become disordered than ordered.
Mixing sugar in tea: once mixed, sugar disperses throughout the tea and
cannot easily be separated — entropy increases.
• Nature & Ecology
Forest fire: a structured ecosystem (trees, biomass) turns into ash, smoke, and
heat — a high-entropy state.
Ecosystem degradation: Pollution or habitat destruction turns a complex, ordered
system into a disordered one — energy is lost & biodiversity declines.
• Human society
Traffic jam: a perfectly flowing system can easily collapse into chaos with just one
disruption — entropy rises.
Ageing: Human bodies, machines, buildings break down over time — order to
disorder.
Game of cards: an ordered deck represents low entropy; shuffling leads to
random order & represents high entropy (more disordered, less predictable).
Climate Change
Scientific “Climate change refers to a change in the state
definition: of the climate that can be identified (e.g., using
statistical tests) by changes in the mean and/or
variability of its properties, & that persists for an
extended period, typically decades or longer”
(IPCC).
“Change of climate, which is attributed directly
4 Climate or indirectly to human activity that alters the
composition of the global atmosphere & which is
Change in addition to natural climate variability observed
over comparable time periods” (UNFCCC).
World Bank: It may be due to natural internal
processes or external forcings such as
modulations of the solar cycles, volcanic
eruptions & persistent anthropogenic (human-
induced) changes in the composition of the
atmosphere or in land use.
• Key Features
Rising global temperatures (global
warming).
Melting glaciers & ice sheets (mass loss
from ice sheets in Greenland & Antarctica
has increased four-fold since the 1990s.
Stokes et al, Nature journal, May 2025).
Rising sea levels (Global mean sea level
increased by around 20 cm from 1901 to
2018. Stokes et al, Nature journal, May
2025).
More extreme weather events –
heatwaves, floods, droughts.
Changing rainfall patterns.
Shifts in ecosystems & biodiversity loss.
• Causes
Greenhouse gas emissions
(atmospheric gases that trap heat &
warm the earth’s surface- CO2,
Methane, etc & human-made
fluorinated gases such as CFC).
Deforestation
Industrial pollution
Agricultural practices
Tuvalu Ministry of Justice, Communication & Foreign Affairs Simon Kofe addresses a speech to
the COP26 while standing in seawater in 2021 highlighting existential threats to Tuvalu & low-
lying small island countries from climate change & sea level rise. Pic: Guardian UK.
Dubai Floods, April 2024 (pic: The Guardian)
Source of all the graphs:
Hannah Ritchie, Pablo Rosado,
& Max Roser (2023) - “Per
capita, national, historical: how
do countries compare on CO2
metrics?” Published online at
OurWorldinData.org.
Retrieved from:
https://ourworldindata.org/co2-
emissions-metrics
Global Warming
5 Global Warming
• The gradual rise of the earth’s surface temperature thought to be caused by
the greenhouse effect & responsible for changes in global climate patterns
(UNFCCC).
• The estimated increase in global mean surface temperature (GMST) averaged
over a 30-year period expressed relative to pre-industrial levels (IPCC).
• Long-term increase in earth’s average surface temperature due primarily to the
buildup of greenhouse gases (CO2, methane, nitrous oxide) in the atmosphere.
• Human activities are estimated to have caused approximately 1.0°C of global
warming above pre-industrial levels, with a likely range of 0.8°C to 1.2°C.
Global warming is likely to reach 1.5°C between 2030 & 2052 if it continues to
increase at the current rate (IPCC Special Report, 2018).
• Caused mainly by human activities: burning fossil fuels (coal, oil, natural gas),
deforestation, industrial emissions, etc.
• Effects include: melting glaciers & polar ice, rising sea levels, warmer oceans.
• Global attempts to limit warming to 1.5°C above pre-industrial levels
(mitigation).
• The values represent temperature anomalies relative to the pre-industrial baseline (1850–1900).
• A clear & sharp rise in temperatures since the mid-20th century, especially after 1980.
Source: IPCC Special Report on Global Warming, 2018
Source:
World
Economic
Forum,
Nov. 2019
Source:
World
Economic
Forum,
Nov. 2019
