Environmental Science: Human Population, Agriculture, Food Security, and Climate Change

Vocabulary review flashcards covering demography, industrial vs. sustainable agricultural practices, pest control, climate dynamics, global environmental policies, and food security.

Thomas Malthus

Author of 'An Essay on the Principle of Population' (1798) who asserted that human population growth is ultimately checked by resource limits, leading inevitably to famine, disease, and war.

Julian Simon

An economist who posited that humans are the 'ultimate resource,' proposing that population growth stimulates technological innovation, which overcomes environmental and resource limits.

Carrying Capacity

The maximum population size of a biological species that an environment can sustain indefinitely given the food, habitat, water, and other necessities available.

Total Fertility Rate (TFR)

The average number of children born to a woman in a population during her lifetime if she experiences the prevailing age-specific fertility rates.

Life Expectancy

The average number of years a newborn infant is expected to live in any given society, which globally rose from 30 to 68 over the twentieth century.

Demographic Transition Model

A historical model tracing the shift from high birth and death rates to low birth and death rates as a society advances economically through four distinct stages: Pre-modern, Urbanizing/Industrializing, Mature/Industrial, and Post-industrial.

$I = PAT$ Model

A conceptual formula that estimates environmental impact ($I$) as the product of population size ($P$), affluence ($A$), and technology ($T$).

Soil Horizons

Distinct horizontal strata constituting a soil profile, specifically the $O$ horizon (organic layer), $A$ horizon (topsoil), $E$ horizon (eluviated layer), and $B$ horizon (subsoil) resting above the parent material.

Contour Plowing

A soil conservation method that involves plowing and planting along the elevation contour lines of a slope to slow water runoff and mitigate soil erosion.

Conventional Agriculture

An industrialized farming system characterized by monoculture crop production and high external inputs of synthetic fertilizers, chemical pesticides, water, and fossil fuel energy.

Earl Butz

The U.S. Secretary of Agriculture appointed in 1971 who urged farmers to plant 'fencerow to fencerow' and 'go big or get out,' driving large-scale agricultural industrialization.

Sustainable Agriculture

Farming practices focused on long-term ecological balance, social equity, and economic viability that utilize low chemical inputs, pasture grazing, and natural soil regeneration.

Biological Control

A pest management strategy that uses living natural enemies—such as predators, parasitoids, or pathogens—to regulate and suppress pest populations.

Pesticide Treadmill

The escalating cycle wherein target pests evolve genetic resistance to repeated chemical applications, forcing farmers to use progressively heavier doses and newer pesticide classes.

Integrated Pest Management (IPM)

An ecologically grounded pest management strategy that integrates knowledge, prevention, monitoring, and mechanical or biological interventions to keep pests below economic threshold levels while reducing pesticide use.

USDA Organic

A third-party verified federal certification confirming that food has been produced without synthetic pesticides, synthetic fertilizers, growth hormones, antibiotics, or genetic engineering.

Weather

The short-term, localized atmospheric conditions of temperature, humidity, cloud cover, and precipitation occurring in the troposphere.

Climate

The synthesized long-term pattern, averages, and variability of temperature, precipitation, and other weather parameters over multi-decadal time spans.

Greenhouse Gases

Gases within the atmosphere—predominantly water vapor, carbon dioxide, methane, and nitrous oxide—that capture and re-emit outgoing terrestrial infrared radiation.

Troposphere

The atmospheric layer adjacent to Earth's surface, reaching an elevation of roughly $18\,\text{km}$ at the equator and $8\,\text{km}$ at the poles, where convection currents generate daily weather patterns.

Coriolis Effect

The apparent deflection of atmospheric winds and ocean currents caused by Earth's eastward axial rotation, curving trajectories to the right in the Northern Hemisphere and to the left in the Southern Hemisphere.

Milankovitch Cycles

Periodic variations in Earth's orbital eccentricity, axial tilt, and precession (axial wobble) that alter the geographical distribution and seasonal intensity of incoming solar radiation.

El Niño (ENSO)

A periodic climatic shift in the equatorial Pacific Ocean marked by slackening trade winds, disrupted ocean currents, and the suppression of cold, nutrient-rich upwelling along western South America.

Anthropogenic

Caused, produced, or influenced directly by human activity, particularly in reference to modern environmental degradation and greenhouse gas emissions.

Carolina Northern Flying Squirrel

An endangered nocturnal gliding mammal whose high-elevation Southern Appalachian spruce-fir forest habitat is increasingly fragmented and threatened by regional warming.

Kyoto Protocol

An international climate agreement adopted in 1997 that established legally binding targets for industrialized nations to decrease greenhouse gas emissions by approximately $5\%$ below 1990 levels by 2012.

Paris Agreement

A 2015 international climate accord signed by 197 countries aimed at keeping global average temperature rise well below $2^\circ\text{C}$ above pre-industrial levels, with efforts to cap it at $1.5^\circ\text{C}$.

Intergovernmental Panel on Climate Change (IPCC)

A scientific and intergovernmental body composed of scientists and government delegates from 130 nations tasked with assessing the state of global climate change science and policy impacts.

Inflation Reduction Act of 2022

U.S. federal legislation utilizing tax incentives and clean energy subsidies with the targeted goal of cutting national carbon emissions by $40\%$ by the year 2030.

Chronic Undernourishment

A state of persistent nutritional shortfall wherein an individual regularly consumes fewer than $2200\,\text{kcal/day}$, leading to physical depletion and health deficits.

Food Security

The condition achieved when all individuals consistently maintain physical, social, and economic access to sufficient, safe, and nutritious dietary energy for a healthy life.

Famine

Acute, widespread food shortage resulting in mass starvation, death, severe economic breakdown, and extensive social collapse.

Food Desert

A neighborhood or geographic sector with inadequate physical access to supermarkets selling fresh produce, typically accompanied by an overabundance of low-cost, processed fast food.

Confined Animal Feeding Operation (CAFO)

A concentrated agricultural facility where livestock are enclosed in dense feedlots and sustained on grain, corn, and soy-based diets to maximize rapid weight gain.

By-catch

Non-target marine organisms, such as seabirds, sea turtles, marine mammals, and non-commercial fishes, accidentally trapped and killed by commercial fishing gear.

Green Revolution

A mid-twentieth-century agricultural shift that substantially expanded global cereal grain output through the breeding of high-yielding crop varieties combined with synthetic fertilizers, pesticides, and intensive irrigation.

High Responders

Specialized crop varieties bred to produce dramatically elevated yields under optimal synthetic fertilizer and moisture levels, but which underperform compared to traditional landraces in low-input conditions.

Genetic Engineering

The laboratory technique of isolating genetic sequences from a donor organism and inserting them into the chromosomes of an unrelated species to produce genetically modified organisms (GMOs) with novel traits.

Goiter

A medical condition featuring an abnormal enlargement of the thyroid gland, typically caused by a chronic dietary deficiency of iodine.

Marasmus

A severe form of protein-energy malnutrition occurring in infants and young children, characterized by extreme muscle and fat wasting caused by a global deficiency of calories and all nutrients.

Andrew Mude

A Kenyan economist who won the 2016 World Food Prize for pioneering satellite-monitored Index-Based Livestock Insurance (IBLI) to provide drought relief to pastoralist herders.