Climate Change

Key Terms and Key Concepts of Climate Change. This page is designed to help you review and master the key terminology and fundamental concepts about Earth's climate system and global warming based on lecture materials.

weather

Local area's physical atmospheric conditions over hours or days.

climate

General pattern of weather conditions over at least 30 years.

Greenhouse Effect

The process by which greenhouse gases trap infrared radiation in Earth's atmosphere, warming the planet's surface.

Greenhouse Gasses

Atmospheric gases including water vapor (60%), carbon dioxide (20%), methane (10%), ozone (5%), and other gases (5% including CFCs) that absorb and re-emit infrared radiation.

Paleoclimatology

The study of past climates prior to the instrument record using climate proxies.

Global Warming

The increase in atmospheric CO₂ over the last ~100 years from 300 ppm to 400 ppm (~33% increase), with temperature rising ~1°C.

Climate Proxies

Indicators used to reconstruct past climates including tree rings, ice cores, lake sediments, coral reefs, ocean sediments, continental coastal sediments, and pollen.

Milankovitch Cycles

Long-term variations in Earth's orbital parameters (eccentricity, axial tilt, and precession) that influence climate patterns over thousands of years.

Snowball Earth

A period 750-580 million years ago when Earth experienced extreme cold temperatures.

Permian Extinction

A mass extinction event 250 million years ago associated with dramatic warming.

mesozoic era

The Age of the Dinosaurs (250-65 million years ago) when Earth was 9°C warmer than now.

Ice Ages

Periods beginning approximately 1 million years ago when Earth was 9°C colder than now, with longer ice ages characterizing this period.

Carbon Isotope Analysis

Changes in carbon isotope abundance (¹³C << ¹²C) indicating more fossil fuel emissions as the source of atmospheric CO₂ increase.

Anthropogenic Forcing

Human-caused factors influencing climate; models using both natural and anthropogenic forcing factors are much closer to actual values than models using only natural factors.

IPCC (Intergovernmental Panel on Climate Change)

Organization with 195 members and thousands of scientists worldwide that conducts volunteering research and peer review, producing assessment reports every ~6 years (1990, 2001, 2005, 2007, 2014, 2021).

Kyoto Protocol (1997)

International agreement committing countries to reduce greenhouse gas emissions.

COP (Conferences of the Parties)

Annual meetings of countries that are parties to the UN Framework Convention on Climate Change.

Paris Agreement (COP21, 2015)

International climate accord setting a 2°C maximum temperature increase above pre-industrial levels, protecting forests, achieving net zero carbon emissions by 2050-2100, and helping developing countries with energy transition.

Mitigation

Actions to reduce emissions and minimize climate impact, such as reducing use of fossil fuels and ending deforestation.

Adaptation

Adjusting to new inevitable conditions by making changes to reduce vulnerability to harmful impacts of climate change.

Geoengineering

The deliberate large-scale manipulation of Earth's climate, including carbon capture and sequestration, sulfur aerosols in stratosphere, iron particles in ocean, and cloud seeding.

Carbon Offsets

The carbon you put in the atmosphere is removed by a counter action through individual action ("free" and limited) or voluntary payment to a company ("cost" but significant).

Cap and Trade

The buying and selling of permits to pollute, with a cap as the maximum limit on pollution allowed by law, where trading of permits is the inverse of offsetting.

Permafrost

Permanently frozen ground that, when melted, releases methane and creates a feedback loop accelerating global warming (the "permafrost timebomb").

Arctic Amplification

The phenomenon where the Arctic experiences larger temperature rises than other regions of the globe.