the science of climate change

Climate Change

Refers to the long-term alteration of temperature and typical weather patterns in a place.

Quaternary Period

The geologic time period marked by significant climate changes, including the Pleistocene and Holocene epochs.

Glaciation

The period of growth and outward spreading of ice sheets, leading to a general cooling of average air temperatures.

Deglaciation

The process of shrinkage of ice sheets in depth and volume, resulting in the receding of ice margins and eventual disappearance of ice sheets.

Last Glacial Maximum (LGM)

The period around 26,000 to 20,000 years ago when ice sheets were at their greatest extent.

Younger Dryas

A period of near full glacial conditions that began and ended suddenly about 11,700 years ago.

Holocene

The geological epoch following the Pleistocene, characterized by fluctuations in climate on a millennial timescale.

Pluvial

Describes any extended period of wet conditions.

Pluvial lakes

Landlocked lakes that fill with water during periods of increased precipitation.

Desiccation

The process of moisture removal, leading to decreased lake levels during dryer interpluvial periods.

Medieval Warm Period

A period from 900-1200 characterized by warmer temperatures in the North Atlantic.

Little Ice Age

A cold period from 1450-1850, particularly affecting western Europe.

Proxy indicators

Evidence derived from sources like ice cores and ocean sediment used to study ancient climates.

Glacier erosion

Features like U-shaped valleys and scratch marks left by glaciers during their expansion.

Glacier deposition

Deposits left by glaciers, known as tillites, containing a wide assortment of sediment sizes.

Oxygen isotope analysis

Technique used to study past climates by analyzing the ratio of oxygen isotopes in calcium carbonate.

Ice cores

Cores extracted from ice sheets used to infer past temperature patterns and atmospheric chemistry.

Sunspots and Climate

Prolonged absence of sunspots correlates with cold periods in Europe and North America, while plentiful sunspots correspond to warmer times in these regions.

Astronomical Theory

Based on variations in the earth's orbit, including eccentricity, obliquity, and precession of the equinoxes, influencing climate through changes in solar radiation distribution.

Variation in Eccentricity

Earth's elliptical orbit affects solar energy received, with changes over thousands of years impacting global climate.

Changes in Obliquity

Earth's axial tilt variations (between 22.1° and 24.5° over 41,000 years) influence seasonal temperature contrasts and ice sheet growth.

Variation in Precession of Equinoxes

Earth's wobbling axis affects the timing of solstices, leading to changes in seasonal contrasts and temperature distribution.

Thermohaline Circulation

Large-scale ocean current movement driven by temperature and salinity differences, crucial for heat transport and maintaining ocean equilibrium.

Changes in Ice Sheets

Growth and retreat of ice sheets influence temperature changes, contributing to glaciation or deglaciation.

Feedback Mechanisms

Complex interactions in the climate system where changes in one variable lead to changes in another, affecting temperature and adding uncertainty to climate predictions.

Positive Feedback Mechanism - Changes in Ice Sheets

Melting ice sheets alter albedo, absorbing more solar energy and amplifying temperature increases.

Changes in Cloud Cover

Clouds act as both negative and positive feedback mechanisms, affecting albedo and temperature regulation in the atmosphere.

IPCC

The Intergovernmental Panel on Climate Change (IPCC) is a scientific body established by the United Nations to evaluate the risk of climate change caused by human activities.

Human Influence on Climate Change

Human activities significantly contribute to climate change by increasing carbon emissions, reducing carbon sinks, and enhancing the greenhouse effect through the concentration of greenhouse gases.

Contemporary Climate Change

Refers to the persistent change in the climate over decades, with the IPCC using the reference period of 1850-1900 as a starting point for observation.

General Circulation Models (GCM)

Sophisticated computer models used to predict the impact of increasing atmospheric carbon dioxide levels on global temperature changes.

Greenhouse Effect

Natural process where certain gases trap longwave radiation in the atmosphere, warming the Earth's surface; without it, the Earth would be much colder.

Greenhouse Gases

Gases like carbon dioxide, methane, nitrous oxide, and chlorofluorocarbons that trap heat in the atmosphere, contributing to the greenhouse effect and global warming.

Greenhouse Gases

Gases responsible for the natural greenhouse effect, with human activities contributing to the enhanced greenhouse effect by emitting more of these gases into the atmosphere.

Carbon Dioxide (CO2)

A significant greenhouse gas that, along with water vapor, plays a crucial role in the greenhouse effect, mainly emitted through the burning of fossil fuels.

Methane (CH4)

Another important greenhouse gas, produced as a by-product of energy consumption and agricultural activities, contributing to global warming.

Deforestation

The process of clearing forests leading to the release of carbon dioxide into the atmosphere, reducing carbon sinks and contributing to climate change.

Carbon Cycle

The circulation of carbon through the Earth's geosphere, atmosphere, and biosphere, involving processes like photosynthesis, combustion, and sequestration, influencing global carbon levels.

Positive Feedback Mechanisms

Factors like deforestation and fossil fuel extraction that amplify the effects of greenhouse gas emissions, leading to increased temperatures and further environmental impacts.

Carbon Capture and Storage (CCS)

A technology aimed at capturing and storing waste carbon dioxide from large sources to prevent its release into the atmosphere, helping to mitigate climate change.

Reforestation and Afforestation

Practices of planting trees to absorb carbon dioxide, acting as negative feedback mechanisms to stabilize atmospheric carbon levels and combat climate change.