ENST midterm - Drivers of Environmental Change

I=PCT formula and ecological footprint

I = Impact on the environment, P = Population size, C = Consumption per person, T = Technology used. Developed countries have higher per capita consumption, leading to larger ecological footprints, while developing countries have lower per capita impact.

Ecological footprint definition

A measure of how much land, water, and other biological resources are needed to sustain a person's lifestyle.

Global hectare definition

A standardized unit measuring the amount of biologically productive land and water required to produce resources and absorb wastes for one person.

Biocapacity definition

The capacity of ecosystems to produce renewable resources and absorb wastes, expressed in global hectares.

Usefulness of ecological footprint

Helps compare consumption levels, identify overuse, highlight inequalities, and motivate changes in personal and societal behavior.

Problems with ecological footprint

Simplifies complex systems, may overemphasize individual responsibility, ignores systemic and technological factors, and can be difficult to measure accurately.

DPSIR model components

D = Drivers, P = Pressures, S = State, I = Impacts, R = Response. Unlike I=PAT, DPSIR incorporates feedback loops and identifies societal responses.

Arithmetic vs physiological density

Arithmetic density = total population per unit land area; Physiological density = population per unit of arable land, reflecting land's carrying capacity.

Why 90% of population is on <20% of land

Most people live in regions with favorable climate, fertile soils, flat topography, economic opportunities, and cultural/political significance.

Factors influencing population distribution

1) Climate → moderate conditions preferred. 2) Topography/soils → flat fertile areas support settlement. 3) Economic → resource availability and jobs. 4) Cultural → religious, historical, or symbolic sites. 5) Political → governance, infrastructure, or refugee migration patterns.

Three determinants of population growth

Births (fertility), deaths (mortality), and migration. Solutions include family planning, education, poverty reduction, and immigration policies.

Factors affecting fertility

1) Economic → industrialization lowers fertility; 2) Cultural → traditions and values influence family size; 3) Education → higher education, especially for women, reduces fertility; 4) Health → access to healthcare and family planning reduces fertility.

High vs low fertility rates

Pre-industrial societies have high fertility due to labor needs and high child mortality. Industrial societies have lower fertility due to urbanization, education, healthcare, and family planning.

Dependency ratio definition

The proportion of non-working-age people (under 15 and over 65) to working-age population (15-65). High ratios increase economic and social pressures.

Challenges of youthful vs elderly populations

Youthful populations: need schools, jobs, healthcare. Elderly populations: need pensions, healthcare, and face shrinking labor forces.

Global migration trends and age demographics

High-income nations attract younger skilled migrants; low-income nations have higher youth populations. Demographics explain patterns of migration toward countries with labor shortages.

Temporary work migrants

Workers move temporarily for jobs; benefits include reduced unemployment and remittances; drawbacks include insecure labor, limited rights, and "brain drain."

Global demographic transition (Hans Rosling)

Global population is transitioning: death rates fall first, then birth rates decline, leading to population stabilization. Some regions are at different stages.

Population pyramids

High-income nations → narrow base, aging population; Low-income nations → wide base, youthful population. Shows age and sex distribution.

Demographic transition diagram

Stage 1: high birth/death → low growth. Stage 2: death declines → high growth. Stage 3: birth declines → slowing growth. Stage 4: low birth/death → stable/declining population. Stage 5 (optional): declining population.

UN medium population projection 2086

Global population expected to peak ~11 billion by 2086; knowing this helps plan resources, sustainability, and policy.

Push factors in migration

Conditions driving people to leave an area, e.g., war, famine, persecution, natural disasters.

Pull factors in migration

Attractive conditions in destination areas, e.g., jobs, safety, education, better living standards.

Forced migration definition

Involuntary relocation due to extreme push factors like war, famine, or environmental disaster. Includes slavery, refugee crises, and conflict-induced displacement.

Rural-urban migration opportunities

Better jobs, education, healthcare, infrastructure, and social mobility.

Rural-urban migration challenges

Overcrowding, slums, unemployment, strain on services, pollution, and social inequality.

Drivers of consumption

1) Basic needs → food, housing, mobility. 2) Social/Cultural → identity, social status, tradition. 3) Market Economics → economic growth requires constant consumption.

Extent of consumption: innate vs manufactured

Some consumption is biological (basic needs), but much is socially and economically manufactured through advertising, social pressures, and capitalist growth imperatives.

Cultural views and consumption

Cultures valuing nature and sustainability may consume less, while consumerist cultures drive higher resource use.

Global trends in consumption

Richest 16% consume ~80% of resources; fastest consumption growth in developing nations; global inequality in resource use.

Environmental costs of consumption

Overexploitation of resources, deforestation, water depletion, overfishing, CO₂ emissions, habitat loss, soil erosion, and ecosystem collapse.

Social costs of consumption

Longer work hours, debt, labor exploitation, systemic inequalities, and vulnerability to economic crises.

Implications of drivers on consumption

Growing population, social norms, and market economies increase pressure on resources, causing ecological overshoot and inequality