CH 14 – The Changing Climate

Quaternary Ice Age

Current ice age that began about 2.6 million years ago.

Global Climate Change

The long-term alteration of temperature and typical weather patterns in a place, highly regarded as occurring due to human influence according to 97% of scientists.

Proxy Data

Indirect measurements that serve as indicators of past climate conditions.

Paleocene-Eocene Thermal Maximum

A warm period in Earth’s history around 55 million years ago, thought to have temperatures 5-9°C higher than today.

Icehouse Periods

Periods in Earth’s history characterized by the presence of extensive ice.

Oxygen Isotope Analysis

A method of studying past climates by analyzing the ratios of oxygen isotopes in marine sediments and polar ice.

Milankovitch Cycles

Natural changes in Earth's orbital parameters affecting solar radiation and climate over long timescales.

Greenhouse Effect

The warming of Earth’s surface due to the trapping of heat by greenhouse gases in the atmosphere.

Albedo

The measure of how much sunlight is reflected from the Earth's surface, affecting climate.

Ocean Acidification

The process by which the ocean becomes more acidic due to increased CO2 absorption, harming marine life.

Positive Feedback Loop

A scenario where a change causes effects that increase the initial change.

Climate Feedback Mechanisms

Processes that can either amplify or diminish the effects of climate change.

Carbon Dioxide (CO2)

A greenhouse gas that significantly contributes to the Earth's warming by absorbing outgoing radiation.

Cretaceous Period

A time in Earth's history (145-66 million years ago) characterized by high levels of CO2 and warm climates.

Solar Variability

Fluctuations in solar energy output, which can influence Earth's climate.

Eccentricity

The shape of Earth's orbit around the Sun, affecting the amount of solar radiation received.

Obliquity

The angle of tilt of Earth's axis, influencing seasonal temperature variations.

Precession

The gradual shift in the orientation of Earth's axis, which affects seasonal climate over thousands of years.

Tectonic Plate Movement

The movement of Earth's outer crust that alters land distribution and climate patterns over geological timescales.

Volcanic Eruptions

Natural events that can rapidly change the climate by releasing ash and gases that block sunlight.

Fossil Pollen

Remnants of pollen used as proxy data to reconstruct past vegetation and climate conditions.

Glacial Periods

Times when global temperatures are cooler and glaciers expand.

Anthropogenic Influence

Human-induced changes that impact the natural environment, specifically regarding climate change.

Tree Rings

Annual growth rings in trees that provide records of climate conditions during specific years.

C14/C12 Ratios

An indicator used to assess fossil fuel contribution to atmospheric carbon by comparing the isotopes of carbon.

Consequences of Climate Change

Effects resulting from climate change, including rising sea levels, changing weather patterns, and ecosystem disruptions.

Heat Stress

Physiological strain due to excessive heat, affecting both human health and biodiversity.

Coral Reefs

Marine ecosystems that are sensitive to changes in ocean temperature and acidity, impacted by climate change.

Weather Variability

Changes in weather patterns that can become more extreme due to climate changes.

Drought

Prolonged periods of abnormally low rainfall, leading to water shortages and agricultural stress.