Geologic Time and Climate Change Study Guide

These flashcards cover key concepts, definitions, and facts related to the geologic time scale, climate change, and major geological events, designed to aid in preparing for an exam.

Paleozoic

An era in the geologic time scale that includes the Cambrian, Ordovician, Silurian, Devonian, Carboniferous, and Permian periods.

Mesozoic

An era in the geologic time scale that includes the Triassic, Jurassic, and Cretaceous periods.

Cenozoic

The most recent era in the geologic time scale, comprising the Paleogene, Neogene, and Quaternary periods.

Seasonality of CO2

The fluctuation of CO2 levels due to plant cycles, with photosynthesis removing CO2 in summer and respiration releasing it in winter.

Natural CO2 range

The range of CO2 levels in the atmosphere over the last hundreds of thousands of years, generally between about 180–300 ppm.

Glacial ice formation

The process where snow compresses into firn and eventually forms glacial ice.

Human CO2 sources

Main sources of anthropogenic CO2 include fossil fuel burning, land-use change, and cement production.

Similar CO2 levels in past

Observed approximately 15–20 million years ago when Earth had warmer temperatures and higher sea levels.

Current CO2 levels

The concentration of CO2 in the atmosphere, currently around 420–430 ppm.

Anthropogenic CO2 rise began

The increase in CO2 levels due to human activities that began during the Industrial Revolution (~1800s).

Evidence of global warming

Indicators such as rising temperatures, melting glaciers, rising sea levels, and ocean acidification.

Sea level rise

An increase in sea level caused by the melting of land ice and the thermal expansion of seawater.

Ocean pH decrease

The process whereby CO2 dissolves in seawater to form carbonic acid, lowering ocean pH.

Environmental successes

Achievements such as the recovery of the ozone layer and the implementation of pollution regulations.

Relative dating

The method used to determine which rocks are older or younger based on their position.

Absolute dating

The method used to determine the numerical age of rocks.

Index fossils

Fossils that are short-lived, widely distributed, and easily recognizable, used for correlating rock layers.

Fossils and geologic time

The appearances and disappearances of fossils are used to define different geological time periods.

Largest extinction

The Permian–Triassic extinction event that occurred approximately 250 million years ago.

James Hutton

Known as the Father of modern geology and the proponent of uniformitarianism.

Law of Superposition

A principle stating that in undisturbed rock layers, older layers are located beneath younger layers.

Unconformity

A gap in the geological record caused by processes such as erosion or non-deposition.

Uniformitarianism

The concept that present geological processes operated in the same way in the past.

Feedback

A response in a system that alters the initial change.

Positive feedback

A process that amplifies change, such as melting ice reducing albedo, leading to more warming.

Negative feedback

A process that stabilizes a system, such as a thermostat regulating temperature.

Equilibrium state

A stable condition of a system that remains unchanged unless disturbed.

Perturbation

A temporary disturbance to a system, for example, a volcanic eruption.

Aerosols

Tiny particles suspended in the atmosphere that can affect climate.

Sulfur and volcanoes

The process by which SO2 from volcanic eruptions forms sulfate aerosols that cool the Earth by reflecting sunlight.

Culture examples

Instances where volcanic eruptions have influenced art or films, like the eruption of Krakatoa.

Super volcano example

A type of volcano that can produce massive eruptions, exemplified by Yellowstone.

K–T extinction

An extinction event caused by an asteroid impact that created dust and sulfur aerosols, blocking sunlight.

Sulfur climate engineering

The theoretical use of sulfur aerosols to reflect sunlight and mitigate warming.

Long-term climate forcing

Persistent changes in greenhouse gases or solar radiation impacting climate over extended periods.

Stable equilibrium

A state where a system returns to balance after a disturbance.

Unstable equilibrium

A state where a system moves further away from balance after a disturbance.

Albedo

A measure of the reflectivity of a surface, indicating how much sunlight is reflected.

High albedo

Surfaces such as ice, snow, and clouds that reflect a significant amount of sunlight.

Low albedo

Surfaces such as oceans and forests that absorb more sunlight than they reflect.

Positive albedo feedback

A process where melting ice exposes darker surfaces, leading to increased warming.

Planet surface temperature controls

Factors influencing planet surface temperatures include solar energy, albedo, and the greenhouse effect.

Habitable zone

The region around a star where conditions are suitable for liquid water to exist.

Dominant solar radiation

The type of radiation from the sun that is mostly visible light.

Temperature vs wavelength

The relationship dictated by Wien’s Law that states hotter objects emit shorter wavelengths.

Earth radiation

The type of radiation emitted by the Earth, primarily infrared radiation.

Electromagnetic spectrum

The range of all types of radiation from radio waves to gamma rays.

Steady state energy budget

A condition where incoming solar energy equals outgoing radiation.

Greenhouse gases

Gases that absorb and re-emit infrared radiation, contributing to the warming of the planet.

N2 and O2 greenhouse gases

Nitrogen and oxygen are not considered greenhouse gases as they do not absorb significant infrared radiation.

Common greenhouse gases

Includes water vapor (H2O), carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), and ozone (O3).

Water vapor variation

The amount of water vapor in the atmosphere is dependent on temperature and the rate of evaporation.

Most abundant atmospheric gases

The primary gases in the atmosphere are nitrogen (78%) and oxygen (21%).

Low-abundance gas impact

Some gases, though present in low quantities, are very effective at absorbing infrared radiation.

Water vapor feedback

A cycle where warming increases evaporation, which in turn increases greenhouse warming.

Flux

The amount of energy passing through a unit area within a specified time.

Solar flux higher at low latitudes

At low latitudes, sunlight is received more directly, leading to higher solar flux.

Tropical energy surplus

An excess of solar radiation absorbed in tropical regions, compared to the radiation emitted.

Energy redistribution

The process by which the atmosphere and oceans distribute heat around the planet.

Ocean surface circulation

The movement of ocean surface water primarily driven by wind patterns.