Glossary of Terms
Absorbed Solar Radiation or ASR - The average global solar radiation received by the Earth’s surface, when clouds are included, which is 240 W/m².
Aerosols – Small particles or droplets such as dust or sulfates in the atmosphere which function as condensation nuclei in the formation of clouds.
Albedo – The reflectivity of a surface measured on a scale of from 0.0 to 1.0 with 1.0 being a perfect reflector of radiation and 0.0 being a perfect absorber of radiation. Black surfaces have a low albedo and brilliant white surfaces have a high albedo.
Anions – Atoms or molecules containing atoms that have a net negative electrical charge due to the addition of one or more valence electrons. The opposite of a cation.
Anthropogenic – human caused or induced.
Aphelion – The point of the orbit of a planet where it is farthest to the Sun. Because the Earth’s orbit is elliptical, it approaches closer and departs farther from the Sun at different points in its orbit.
Black Body – A theoretical body that absorbs all radiation and emits all of this radiation. As an object moves from black to white, the albedo changes. A Black Body has 0.0 albedo and reflects no light. The Planck black body curve is the distribution of electromagnetic radiation emitted by a black body at a given temperature.
Carbon Footprint – A term to describe the amount of carbon dioxide produced from various human activities.
Cations – Atoms or molecules containing atoms that have a net positive electrical charge due to the removal of one or more valence electrons. The opposite of an anion.
CCN – An abbreviation for Cloud Condensation Nuclei which are tiny particles in the atmosphere on which water vapor condenses to form cloud droplets. Water vapor in the air almost always condenses on hydrophilic (water attracting) particles which are considered essential for cloud formation.
Celsius – A basic measure of temperature in the metric system where 0 degrees Celsius is the freezing point of water and 100 degrees Celsius is the boiling point of water. Often transcribed as degrees C or ºC.
CFCs – The halogen gases chlorofluorocarbons (CFCs) that were used as refrigerants, aerosol can propellants, and halogen fire extinguishers. CFCs are powerful greenhouse gases. Use of CFCs were effectively banned globally by the Montreal Protocol and atmospheric concentrations of CFC are declining. They have been replaced primarily by hydrofluorocarbons (HFCs).
Clausius-Clapeyron Principle – How the vapor pressure of a substance (like water vapor in air) changes with temperature. The principle explains why air can hold 7% more moisture for each one-degree Celsius increase in temperature, at constant pressure.
CLAW Hypothesis – A proposed cooling climate feedback between ocean biology and cloud formation named after its four proponents, Charlson, Lovelock, Andreae, and Warren. The theory suggests that warming oceans stimulate phytoplankton growth which releases more dimethyl sulfide (DMS) into the atmosphere, which creates more sulfate cloud condensation nuclei and more cloud cover, which lowers temperature.
Climate Feedbacks – Processes that can either increase or decrease the effects of climate forcing. For example, the sun is a climate forcing that warms the Earth. As the Earth warms, more water evaporates from the ocean forming more low clouds, which reflects sunlight off the clouds back out to space and reduces the warming. This is a negative feedback because it counteracts warming from the sun. Clouds also have a positive feedback as they absorb and emit some heat back to Earth.
Climategate – An unauthorized release of thousands of emails in 2009 from the Climate Research Unit at the University of East Anglia. The emails suggested leading climate scientists associated with the IPCC manipulated data to confirm human induced climate warming, interfered with the peer review process, conspired to hide data that did not conform with the climate crisis narrative, sought to boycott a scientific journal that published views skeptical of the climate crisis narrative, and colluded to pressure the firing of editors of this journal.
CO² – The chemical formula of carbon dioxide, which consists of one carbon atom and two oxygen atoms.
Cosmic Rays – Highly energetic atomic particles, primarily protons, traveling through space at speeds approaching the speed of light. They are primarily created by exploding stars outside of our solar system.
Dark Ages – A cold period between ~400 CE to ~900 CE during which the fall of both the Roman Empire and the Tang Dynasty in China occurred. The cold period encompasses the “Migration Era Pessimum” and the “Late Antique Little Ice Age” that saw cold temperatures, famines, climate migrations, and civilization decline.
DMS – A sulfur-containing organic compound dimethyl sulfide ((CH₃)S). DMS is produced mainly by marine phytoplankton and is oxidized to form sulfate cloud condensation nuclei around which clouds are formed.
Eccentricity – The ~100,000-year cycle of periodic changes in the shape of the Earth’s orbit around the Sun, changing from near circular to slightly elliptical. Eccentricity is one of the three main Milankovitch cycles that influence the Earth’s climate.
Energy Budget – Also known as the Energy Balance, the Energy Budget is the principle that the same amount of energy introduced to the Earth, primarily from solar heating, is reflected and radiated out to space in the form of infrared radiation. Because the heat in equals the heat out, the energy budget keeps the climate stable. If the system is not in balance the net result is heating or cooling.
EPA – Environmental Protection Agency, a scientific and regulatory agency of the United States government tasked to protect human health and the environment by controlling pollution.
Equilibrium – In thermodynamics, equilibrium is a steady state of constant temperature after heat is transferred from one object to another resulting in the same temperature for each object.
ESG – Environmental Social and Governance, a framework to evaluate the practices and performance of companies and countries on sustainable and ethical issues, including anthropogenic climate change. ESG is used by the World Bank and other financial institutions as one measure in qualifying organizations to receive loans.
Extra-Tropics – The regions of the globe between the Tropics and the Polar Circles. The Extra-Tropics are located between 23.5 degrees north and south latitudes to 66.5 degrees north and south latitudes.
Ferrel Cell – An atmospheric circulation pattern that moves heat from the Earth’s surface to the poles from about 30 degrees latitude to 60 degrees latitude and moves the heat upward into the top of the troposphere at about 60 degrees latitude and back to 30 degrees latitude where it is returned to the surface. There is both a Northern Hemisphere Ferrel Cell and a Southern Hemisphere Ferrel Cell.
Forbush Decrease Event – A solar flare that causes a rapid drop in the intensity of galactic cosmic rays reaching the Earth for a period of 3-day to 10-day, or longer. Known as a Forbush Decrease, the effects are reduced ionization in the atmosphere and changes in cloud formation. First discovered by Scott Forbush in the 1930s.
GDP – Gross Domestic Product, a monetary measure of economic growth or decline of a country’s economy, measured as a percent of annual growth or decline from the total of all goods and services produced in such economy.
Greek Dark Ages – A cold period between ~1100 BC to ~800 BC when the Bronze Age civilizations collapsed in the Eastern Mediterranean and China.
Greenhouse Gases – Gases in the atmosphere which absorb and emit radiation including water vapor, carbon dioxide, ozone, methane, nitrous oxide, and hydrofluorocarbons. Because greenhouse gases absorb infrared radiation and emit some of that radiation back to Earth, the net effect of greenhouse gases is to warm the Earth.
Gulf Stream – A circular ocean current that carries warm water from the Caribbean seas to the North Atlantic.
Hadley Cell – An atmospheric circulation pattern that moves heat near the equator up to the top of the troposphere and moves it back to Earth at about 30 degrees latitude where it circulates on the surface back to the equator. There is both a Northern Hemisphere Hadley Cell and a Southern Hemisphere Hadley Cell.
Henry’s Law – A law of nature that states the amount of gas that dissolves in a liquid is proportional to the pressure of the gas above the liquid and the temperature of the liquid. More gas dissolves in colder liquids and less gas dissolves in warmer liquids. As a liquid is heated, dissolved gas escapes from the liquid because the solubility of the gas in the liquid decreases.
HFCs - The halogen gases hydrofluorocarbons (HFCs) that have significantly replaced chlorofluorocarbons (CFCs) for use as refrigerants, aerosol can propellants, and halogen fire extinguishers. HFCs are powerful greenhouse gases. The use of long-lived HFCs has been banned by the Kigali Amendment to the Montreal Protocol and as a result, atmospheric concentrations of HFCs are expected to decline.
Hydrophilic – Substances that attract and absorb water. The opposite of hydrophobic substances which repel water.
Holocene – The current interglacial period of the Earth’s geological history. The Holocene began about 11,700 years ago following the end of the last major ice age and continues to present times.
Holocene Climatic Optimum – The warmest period of the current Holocene interglacial period, which occurred around 7,000 BC to 3,000 BC. Also known as the Holocene Thermal Maximum.
Infrared Radiation – Electromagnetic radiation from a spectrum of relatively long wavelengths that radiates heat from the Earth to space.
Interglacial Period – A geological interval of warmer global temperatures that occurs between glacial periods (ice ages) during an ice age cycle. During interglacial periods, glaciers and ice sheets retreat, sea levels rise, and ecosystems expand into higher latitudes.
IPCC – Intergovernmental Panel on Climate Change – A body of the United Nations whose mission is to advance the scientific knowledge about climate change caused by human activities.
ITCZ – Intertropical Convergence Zone, the region between the Northern Hadley Cell and the Southern Hadley Cell, usually near and slightly north of the equator.
Isotopes - Isotopes are variations of atomic elements that have a varied number of neutrons. Isotopes of an atomic element possess the same chemical properties because they have the same number of protons and electrons. Accordingly, isotopes look and behave the same in nature, but they have different masses. Mass spectrometry can be used to measure and differentiate isotopes. For example, a sample of carbon can be analyzed by mass spectrometry to determine its composition of Carbon-12 (¹²C), Carbon-13 (¹³C), and Carbon-14 (¹⁴C). Likewise mass spectrometry can analyze water to determine the mixture of water (¹H₂0), deuterium heavy water (²H₂O), and tritium heavy water (³H₂O) in the sample.
Kelvin – Kelvin is a basic unit of measurement of temperature on the same per unit scale as Celsius, but 0 Kelvin is at absolute zero (-273.15ºC), whereas 0 degrees Celsius is at the freezing point of water. Often transcribed as K.
Kuroshio Current – A current that carries warm water from the Philippines up the coast past Japan and warms the North Pacific Ocean.
Late Antique Little Ice Age – A period between 536 CE to 660CE that experienced abrupt global cooling. Volcanic eruptions and a great solar minimum are deemed to be the cause of the cooling. The result was glacier growth, droughts, shorter growing seasons, and reduced agricultural productivity. Crop failure and famine led to an increase of plagues and sociopolitical upheaval in the Roman/Byzantine Empire and in Mesoamerica.
Little Ice Age – A global cold period between 1300 CE to 1850 CE.
Medieval Warm Period –An interval of warmth of the globe, especially the North Atlantic and China, between the years ~950 CE to ~1300 CE. Also known as the Medieval Optimum due to the prosperity of the times.
Meridional Overturning Circulation (MOC) – Also known as the Thermohaline Ocean Circulation. An ocean current that carries warm water from the Tropics to the Polar regions of the globe, especially the North Atlantic.
Milankovitch Cycles – Changes in the Earth’s orbital shape, axial tilt, and a rotational progression in the orientation of the Earth’s axis which result in climate changes over tens of thousands of years. These cycles influence the amount of solar radiation received by the Earth, contributing to climatic changes on Earth over prolonged periods. Over ~100,000 years, the Earth’s orbital shape cycles from more elliptical around the sun to less elliptical, which is known as eccentricity. The tilt of the Earth changes every ~41,000 years from 22.1 degrees to 24.5 degrees. Known as obliquity, this further changes the climate. The third cycle impacting the climate, known as precession, is a rotation of the Earth’s axis relative to its orbit around the Sun, about every 23,000 years.
Minoan Warm Period – A period of warmth during the Bronze Age in the Eastern Mediterranean region ~1500 BC to ~1200 BC. Also known as the Bronze Age Optimum.
Montreal Protocol – An international treaty agreed to in 1987 to eliminate chlorofluorocarbons (CFCs) and other ozone depleting chemicals. The treaty has been successful in virtually eliminating the industrial use of CFCs. Signed in 2019, the Kigali Amendment to the Montreal Protocol will phase down long-lived hydrofluorocarbons (HFCs). Since both CFCs and HFCs are powerful greenhouse gases, the Montreal Protocol and its Kigali Amendment are important agreements in controlling future radiative forcing from greenhouse gases.
Moraines - Dirt, rocks, and debris transported by glaciers, which are used to estimate the historical glacier advances or retreats.
Myhre, et. al., Radiative Forcing Equations – Equations to estimate the radiative forcing (heating) produced by changing concentrations of greenhouse gases. These equations were first proposed in a paper published in 1998 by Gunnar Myhre, et. al. and are accepted by the IPCC to estimate radiative forcing. The Myhre equations provide Instantaneous Radiative Forcing and need to be adjusted to determine Effective Radiative Forcing, which more accurately captures the greenhouse gas impact on the Earth’s Energy Budget and resulting temperature changes.
NASA – National Aeronautics and Space Administration, a government agency of the United States whose mission is to investigate the unknown in air and space for the benefit of humanity.
NOAA – National Oceanic and Atmospheric Administration, a scientific and regulatory government agency of the United States whose mission is to understand and predict changes in climate, weather, oceans, and coastlines.
Obliquity – The ~41,000-year cycle of periodic changes in the tilt of the Earth’s axis relative to its orbital plane, changing from 24.5ᵒ to 22.1ᵒ. Obliquity is one of the three main Milankovitch cycles that influence the Earth’s climate.
Paleoclimate – The science of using proxy measurements such as isotopes of carbon, oxygen, and beryllium in ice cores, tree rings, sea beds, speleothems, and other geological samples and measures to estimate temperature and other climate parameters of past ages.
Palynology – The study of pollen fossils, used as a proxy to understand plant growth and agriculture in ancient and pre-historic times.
Perihelion – The point of the orbit of a planet where it is closest to the Sun. Because the Earth’s orbit is elliptical, it approaches closer and departs farther from the Sun at different points in its orbit.
Polar Cell - An atmospheric circulation pattern that moves heat around 60 degrees latitude up to the top of the troposphere and moves it back to Earth at the poles where it circulates on the surface back to about 60 degrees latitude. There is both a Northern Polar Cell and a Southern Polar Cell.
Polar Vortex – A large mass of circulating frigid air in the stratosphere, comprised of strong winds that circulate around the globe counterclockwise in the Arctic and clockwise in Antarctica. When the polar vortex is strong it keeps frigid air in the polar region, when it is weak, it becomes wavy moving cold air from the polar region to lower latitudes and warmer air into the polar regions.
Precession – The ~23,000-year cycle of periodic rotational shift in the orientation of the Earth’s axis, relative to its orbit around the Sun, changing the season of when the Earth is in perihelion or aphelion. Precession is one of the three main Milankovitch cycles that influence the Earth’s climate.
Quantum Physics – The science of physics of matter and energy at the atomic and subatomic level.
Radiative Forcing – The warming process of a climate driver, usually measured in watts per square meter.
Roman Warm Period – An interval of warmth of the globe between the years 250 BC to 400 CE. Also known as the Roman Optimum due to the prosperity of the times.
Seed Clouds – The process where water condenses on solid and liquid aerosol particles to form clouds. Aerosols function as condensation nuclei, or seeds, for water vapor condensation.
Speleothem – A mineral deposit formed in cave stalactites and stalagmites from groundwater. They are commonly composed of calcium carbonate (CaCO₃). The oxygen in the calcium carbonate can be analyzed by mass spectrometry to determine the ratio of ¹⁶O to ¹⁸O isotopes, which is a proxy of past temperature.
Stratosphere – The second layer of the atmosphere above the troposphere extending about 50 kilometers from the surface of the Earth. Ozone in the stratosphere blocks much of the ultraviolet radiation from the sun and prevents it from reaching the Earth’s surface.
Stefan-Boltzmann Law – A natural law where the total energy radiated per unit surface area of a black body is directly proportional to the fourth power of its absolute temperature. Temperature is thus the fourth root of the energy divided by the Stefan Boltzmann constant. Therefore, it takes exponentially more energy to increase temperature linearly.
Sudden Stratospheric Warming (SSW) Event – A rapid increase in temperature in the stratosphere over the polar regions produced by waves of a weak polar vortex.
Temperature Anomaly – The difference between observed temperature and a baseline temperature.
The Big Freeze – A term coined by Time magazine on December 3, 1973, to describe the cooling event between the mid-1940s to the mid-1970s. Some scientists predicted this period was the start of a new Ice Age.
Thermohaline Current – An antiquated name for the Meridional Overturning Circulation or MOC. An ocean current that carries warm water from the Tropics to the Polar regions of the globe, especially the North Atlantic.
Tropics – The region of Earth surrounding the equator, roughly between the Tropic of Cancer (23.5 degrees north latitude) to the Tropic of Capricorn (23.5 degrees south latitude).
Troposphere – The first layer of the atmosphere that extends from the Earth’s surface to a height of 6 to 10 kilometers. The troposphere is where most weather occurs.
Twomey Effect – The increased reflectivity of clouds which are composed of small droplets formed from water vapor condensing on sulfate aerosols. The smaller droplet-size scatters light more effectively, making clouds brighter and more reflective. This observation was first described by Sean Twomey in the 1970s and has been confirmed by observational data.
Ultraviolet Radiation – Electromagnetic radiation from a spectrum of relatively short wavelengths that strikes the Earth primarily from the sun. Much of the ultraviolet spectrum of radiation is absorbed in the upper atmosphere, but some does reach the surface of Earth and results in warming the Earth.
Visible Light – Electromagnetic radiation from a spectrum of medium wavelength that is visible to the human eye. The spectrum between ultraviolet and infrared light.
