Midterm 2 Review: Planetary Boundaries, Environmental Systems, and Policy

Vocabulary practice flashcards covering topics from Midterm 2 Review, including planetary boundaries, climate change dynamics, energy transitions, soil remediation, environmental justice, stream and urban ecology, and atmospheric chemistry.

Holocene

The geological epoch spanning the past 10,000 years characterized by very stable environmental conditions and a stable human population.

Anthropocene

The current geological epoch in which human activity has become a major causal factor altering Earth systems and climate.

Replacement Fertility Rate

The total fertility rate required for a population to replace itself from one generation to the next without migration, identified as $2.1$.

Resilient System

A system in a steady state where a disturbance causes a temporary change, but the system possesses the capacity to return back to normal.

Planetary Boundaries

A framework identifying nine critical Earth system thresholds where exceeding the boundary moves the system into a zone of increasing risk.

Carbon Intensity

The amount of $CO_2$ emitted per unit of economic output, determined by energy generation efficiency and the adoption of renewable energy.

Kaya Identity

A mathematical formulation represented as $E = P \times GDP \times F$ used to estimate total emissions from population ($P$), GDP per capita ($GDP$), and carbon intensity ($F$).

Climate Feedback

A process in which two components of an Earth system influence each other, such that a change in one causes an effect that amplifies or dampens the initial change.

El Niño

A major multi-year or decadal climate variability phenomenon centered in the tropical Pacific Ocean that significantly elevates average global temperatures.

Wright's Law

The principle stating that with every doubling of cumulative production of a technology, its costs decrease by a fixed percentage (e.g., $20\%$ for solar photovoltaic panels).

Point Source Pollution

Soil or environmental contamination that originates from a single, identifiable, and localized discharge source.

Non-Point Source Pollution

Diffuse contamination resulting from multiple scattered inputs across a wide geographic area rather than a single distinct source.

Phytoremediation

A sustainable soil remediation technique that uses green plants to remove, contain, or neutralize contaminants.

Biostimulation

A remediation process that accelerates the breakdown of pollutants by adding nutrients like nitrogen ($N$) and phosphorus ($P$) to stimulate native microbial populations.

Natural Attenuation

A passive, sustainable remediation method where existing natural microorganisms slowly break down contaminants over time, suitable only for low-grade hazards.

Assembly Bill 685 (AB 685)

A landmark 2012 California law declaring that every human being has the right to safe, clean, affordable, and accessible drinking water.

Urban Ecology

The study of the interconnected social and ecological relationships in urban environments, highlighting the explicit role of humans in ecosystem dynamics.

Luxury Effect

The ecological observation that urban species richness and biodiversity are positively correlated with socioeconomic wealth, especially in areas with longstanding wealth.

Autochthonous

Organic matter or nutrients produced internally within a stream ecosystem, such as by aquatic algae and microbes.

Allochthonous

Nutrients and organic energy sources originating from outside the stream channel, such as terrestrial plant leaves falling into the water.

Riparian Zone

The terrestrial vegetated zone bordering a river or stream that directly connects land-based food webs to aquatic food webs.

River Continuum Concept

A model stating that river ecosystems change predictably from headwaters ($R > P$, allochthonous-dominated) to mid-reaches ($P > R$, autochthonous-dominated) to lower reaches ($R > P$, cloudy collector-dominated).

Biomonitoring

The assessment of long-term ecological conditions and water quality by observing the health, abundance, and diversity of living organisms.

Benthic Macroinvertebrates

Bottom-dwelling aquatic insects and larvae that serve as reliable bioindicators due to their diverse range of pollution tolerances and widespread presence.

EPT Families

A group of aquatic macroinvertebrates comprising mayflies (Ephemeroptera), stoneflies (Plecoptera), and caddisflies (Trichoptera), known for high sensitivity to water pollution.

Access Theory

An environmental justice theory positing that individuals may have resource access without formal legal rights, or formal rights without real resource access.

Critical Race Theory

A framework examining how structural racism is embedded within legal statutes, institutions, and policies to uphold unequal racial power dynamics.

Homestead Act (1862)

United States legislation that accelerated westward expansion by transferring ownership of indigenous lands to white settlers.

Morrill Act (1862)

United States legislation that transferred expropriated indigenous lands to finance and endow public university systems across the nation.

Redlining

Historical institutional discrimination in housing finance that created persistent, modern-day disparities in pollution exposure, toxic waste siting, and green space.

Backcasting

A planning framework that defines a desirable future goal first, then works backwards to identify policies and actions needed in the present to achieve it.

Market Failure

An economic scenario in which a free market fails to allocate scarce resources efficiently to maximize value and minimize waste.

Social Cost

The total cost of an economic transaction to society, calculated as private costs plus external costs (e.g., healthcare burdens and environmental degradation).

California Senate Bill 100 (SB 100)

A California clean energy policy establishing renewable and zero-carbon grid targets of $50\%$ by 2026, $60\%$ by 2030, and $100\%$ by 2045.

Photochemical Smog

Secondary air pollution formed when nitrogen oxides ($NO_x$) and volatile organic compounds ($\text{VOCs}$) react in the presence of sunlight to generate ozone ($O_3$) and particulate matter.

Temperature Inversion

A meteorological condition where warm air caps a cooler layer of stagnant air near the ground, trapping primary air pollutants against geographical barriers.

Chapman Mechanism

The foundational four-stage photochemical sequence governing stratospheric ozone production and natural destruction through reactions involving $O_2$, $O$, and $O_3$.

Catalytic Ozone Destruction

A catalytic cycle where a free radical catalyst $X$ (such as $NO_x$, $ClO_x$, $HO_x$, or $BrO_x$) reacts with $O_3$ and is regenerated by atomic $O$, resulting in the net breakdown of $O_3 + O \rightarrow 2O_2$.

Polar Stratospheric Clouds

Clouds that form in the extremely cold polar winter stratosphere, providing surfaces that facilitate the chemical conversion of stable precursor compounds into active ozone-destroying catalysts.

Montreal Protocol (1989)

An international environmental agreement designed to protect the stratospheric ozone layer by phasing out the production and emission of ozone-depleting substances, primarily chlorofluorocarbons (CFCs).