Week 4: Stratospheric Ozone Depletion and Greenhouse Gas Effects

These flashcards cover key concepts relating to stratospheric ozone depletion, the impact of greenhouse gases, and associated environmental policies.

Ozone Hole

A region with significantly decreased ozone concentration in the stratosphere.

Stratospheric Ozone (O3) Concentration

The amount of ozone present in the stratosphere, commonly measured in Dobson Units (DU).

Dobson Units (DU)

A unit of measure for atmospheric ozone concentration; 290 DU is considered the preindustrial level.

Troposphere

The lowest layer of Earth's atmosphere, where weather occurs, extending from the surface up to about 20 km.

Stratosphere

The atmospheric layer above the troposphere, extending from 20 km to 50 km above Earth's surface.

Tropopause

The boundary between the troposphere and the stratosphere.

CFCs (Chlorofluorocarbons)

Man-made chemical compounds responsible for ozone depletion, used in refrigeration and aerosol products.

Montreal Protocol

An international treaty aimed at phasing out substances that deplete the ozone layer, including CFCs.

UV Radiation

Ultraviolet radiation from the sun that can cause damage to living organisms; its types include UV-A, UV-B, and UV-C.

Ozone Formation

Occurs when UV radiation splits O₂ molecules, leading to the formation of ozone (O₃) through a reaction with free oxygen atoms.

Ozone Destruction

The breakdown of ozone molecules often accelerated by human-made chemicals such as CFCs.

Atmospheric Layers

Different layers of the atmosphere, including troposphere, stratosphere, mesosphere, thermosphere, and exosphere.

Planetary Boundary

A threshold that indicates how much change can occur in a planetary system without causing irreversible damage.

Skin Cancer Prevention

The reduction of skin cancer cases attributed to the ozone layer's ability to absorb harmful UV radiation.

Chlorine Role in Ozone Depletion

Chlorine released from CFCs acts as a catalyst in reactions that breakdown ozone.

Polar Stratospheric Clouds

Clouds that form in the stratosphere at very low temperatures, providing surfaces for ozone-depleting reactions.

Antarctic Ozone Hole

A significant thinning of the ozone layer that occurs over Antarctica, particularly noticeable in spring.

Environmental Policy Success

The Montreal Protocol serves as a model due to its clear science, global cooperation, and effective regulation.

Ozone Recovery Projections

Predictions on the return of atmospheric ozone levels to pre-depletion levels, expected by mid-21st century.

Greenhouse Gases (GHGs)

Gases that trap heat in the atmosphere, contributing to the greenhouse effect and climate change.

Carbon Cycle

The continuous movement of carbon through the atmosphere, biosphere, lithosphere, and hydrosphere.

Fossil Fuel Emissions

Carbon dioxide emissions released into the atmosphere from the burning of fossil fuels, contributing to climate change.

UV-A Radiation

Longer wavelength UV radiation that is partially absorbed by the ozone layer (50% absorption).

UV-B Radiation

Medium wavelength UV radiation that is largely absorbed by the ozone layer (90% absorption).

UV-C Radiation

The shortest wavelength UV radiation, completely absorbed by the ozone layer.

Chemical Mechanism for Ozone Destruction

The process by which stable compounds like CFCs break down to release chlorine, contributing to ozone depletion.

Ozone's Role in Temperature Regulation

Ozone absorbs UV radiation, leading to temperature increases in the stratosphere.

Surface Air Pollution

Pollutants in the atmosphere from human sources, significantly affecting air quality and health.

Aerosols

Tiny particles in the atmosphere that can affect climate and health, originating from natural and anthropogenic sources.

Condensation Nuclei

Particles such as aerosols that serve as surfaces for water vapor to condense, essential for cloud formation.

Aerosol Optical Depth (AOD)

A measure of how aerosols prevent sunlight from reaching the Earth's surface, with implications for air quality and climate.

End-of-Century Projections

Predictions regarding future atmospheric conditions and the expected recovery of the ozone layer.

Anthropogenic Effects

Human-induced changes to the environment, particularly in relation to emissions and atmospheric composition.