Environmental Science: Climate, Atmosphere, and Human Impact Key Concepts

Scientific communication

Peer-reviewed scientific writing (journal articles) used to communicate research methods, data, and conclusions.

Anthropogenic change

Environmental change originating from human activity, such as pollution, deforestation, greenhouse gas emissions, or climate change.

Ozone layer depletion

The destruction of stratospheric ozone by human-made CFCs, reducing protection from harmful UV radiation.

Weather

Short-term atmospheric conditions (hours to days), including temperature, precipitation, wind, and humidity.

Climate

Long-term average atmospheric conditions, typically measured over 30 years or more.

Keeling Curve

A continuous record of atmospheric CO₂ concentration measured since 1958 at Mauna Loa Observatory.

Ice cores

Long-term climate records that measure ancient atmospheric gases trapped in ice bubbles.

Seasonal CO₂ cycle

The annual rise and fall of CO₂ due to Northern Hemisphere plant growth and decay.

Geologic time order

Eon → Era → Period → Epoch

Cenozoic epochs

Paleocene → Eocene → Oligocene → Miocene → Pliocene → Pleistocene → Holocene

Cretaceous-Paleogene extinction evidence

High iridium concentrations indicating a massive asteroid impact.

Gaia Hypothesis

The idea that Earth is a self-regulating system where life interacts with the environment to maintain conditions favorable for life.

System

An entity composed of interrelated components whose state is defined by key attributes at a given time.

Feedback loop

A process where a system response influences the original change.

Negative feedback

A feedback that stabilizes a system by reducing the effects of disturbances.

Positive feedback

A feedback that amplifies changes and drives the system away from equilibrium.

Albedo

The fraction of incoming solar radiation reflected by a surface.

Daisyworld temperature control

Daisy coverage affects albedo, which controls average surface temperature.

Daisyworld feedback loop

More daisies increase albedo, reflect sunlight, cool the planet, and limit further daisy growth.

Greenhouse Effect

The warming of Earth caused by atmospheric absorption and re-emission of infrared radiation.

Major atmospheric gases

Nitrogen (~78%), Oxygen (~21%), Argon (~0.93%), Carbon dioxide (~0.04%), plus trace gases.

Atmospheric layers

Exosphere → Thermosphere → Mesosphere → Stratosphere → Troposphere

Greenhouse gas absorption

Greenhouse gases absorb infrared radiation due to molecular vibration and rotation.

Why O₂ and N₂ do not absorb IR

They are symmetric molecules with no changing electric dipole moment.

Clouds and climate

Clouds increase albedo (cooling) and absorb infrared radiation (warming).

Global Energy Budget

The balance between incoming solar radiation and outgoing infrared radiation, regulated by greenhouse gases.