Chlorofluorocarbon in the context of Halogenation

Greenhouse gases (GHGs) are the gases in an atmosphere that trap heat, raising the surface temperature of astronomical bodies such as Earth. Unlike other gases, greenhouse gases absorb the radiations that a planet emits, resulting in the greenhouse effect. The Earth is warmed by sunlight, causing its surface to radiate heat, which is then mostly absorbed by greenhouse gases. Without greenhouse gases in the atmosphere, the average temperature of Earth's surface would be about −18 °C (0 °F), rather than the present average of 15 °C (59 °F). Human-induced warming has been increasing at a rate that is unprecedented in the instrumental record, reaching 0.27 [0.2–0.4] °C per decade over 2015–2024. This high rate of warming is caused by a combination of greenhouse gas emissions being at an all-time high of 53.6±5.2 Gt CO2e yr−1 over the last decade (2014–2023), as well as reductions in the strength of aerosol cooling.

The five most abundant greenhouse gases in Earth's atmosphere, listed in decreasing order of average global mole fraction, are: water vapor, carbon dioxide, methane, nitrous oxide, ozone. Other greenhouse gases of concern include chlorofluorocarbons (CFCs and HCFCs), hydrofluorocarbons (HFCs), perfluorocarbons, SF
₆, and NF
₃. Water vapor causes about half of the greenhouse effect, acting in response to other gases as a climate change feedback.

Liquefied petroleum gas, also referred to as liquid petroleum gas (LPG or LP gas), is a fuel gas which contains a flammable mixture of hydrocarbon gases, specifically propane, n-butane and isobutane. It can also contain some propylene, butylene, and isobutylene/isobutene.

LPG is used as a fuel gas in heating appliances, cooking equipment, and vehicles, and is used as an aerosol propellant and a refrigerant, replacing chlorofluorocarbons in an effort to reduce the damage it causes to the ozone layer. When specifically used as a vehicle fuel, it is often referred to as autogas or just as gas.

This article is a list of locations and entities by greenhouse gas emissions, i.e. the greenhouse gas emissions from companies, activities, and countries on Earth which cause climate change. The relevant greenhouse gases are mainly: carbon dioxide, methane, nitrous oxide and the fluorinated gases bromofluorocarbon, chlorofluorocarbon, hydrochlorofluorocarbon, hydrofluorocarbon, nitrogen trifluoride, perfluorocarbons and sulfur hexafluoride.

The extraction and subsequent use of fossil fuels coal, oil and natural gas, as a fuel source, is the largest contributor to global warming.

Hydrofluorocarbons (HFCs) are synthetic organic compounds that contain fluorine and hydrogen atoms, and are the most common type of organofluorine compounds. Most are gases at room temperature and pressure. They are frequently used in air conditioning and as refrigerants; R-134a (1,1,1,2-tetrafluoroethane) is one of the most commonly used HFC refrigerants. In order to aid the recovery of the stratospheric ozone layer, HFCs were adopted to replace the more potent chlorofluorocarbons (CFCs) such as R-12, which were phased out from use by the Montreal Protocol, and hydrochlorofluorocarbons (HCFCs) such as R-21 which are presently being phased out. HFCs are also used in insulating foams, aerosol propellants, as solvents and for fire protection.

HFCs may not harm the ozone layer as much as the compounds they replace, but they still contribute to global warming – with some like trifluoromethane (CHF₃ or R-23) having 11,700 times the warming potential of carbon dioxide. HFC atmospheric concentrations and contribution to anthropogenic greenhouse gas emissions are rapidly increasing – consumption rose from near zero in 1990 to 1.2 billion tons of carbon dioxide equivalent in 2010 – causing international concern about their radiative forcing.

Mario José Molina-Pasquel Henríquez (19 March 1943 – 7 October 2020) was a Mexican physical chemist. He played a pivotal role in the discovery of the Antarctic ozone hole, and was a co-recipient of the 1995 Nobel Prize in Chemistry for his role in discovering the threat to the Earth's ozone layer from chlorofluorocarbon (CFC) gases. He was the first Mexican-born scientist to receive a Nobel Prize in Chemistry and the third Mexican-born person to receive a Nobel prize.

In his career, Molina held research and teaching positions at University of California, Irvine, California Institute of Technology, Massachusetts Institute of Technology, University of California, San Diego, and the Center for Atmospheric Sciences at the Scripps Institution of Oceanography. Molina was also Director of the Mario Molina Center for Energy and Environment in Mexico City. Molina was a climate policy advisor to the President of Mexico, Enrique Peña Nieto.

Frank Sherwood "Sherry" Rowland (June 28, 1927 – March 10, 2012) was an American Nobel laureate and a professor of chemistry at the University of California, Irvine. His research was on atmospheric chemistry and chemical kinetics. His best-known work was the discovery that chlorofluorocarbons contribute to ozone depletion.

North Atlantic Deep Water (NADW) is a deep water mass formed in the North Atlantic Ocean. Thermohaline circulation (properly described as meridional overturning circulation) of the world's oceans involves the flow of warm surface waters from the southern hemisphere into the North Atlantic. Water flowing northward becomes modified through evaporation and mixing with other water masses, leading to increased salinity. When this water reaches the North Atlantic, it cools and sinks through convection, due to its decreased temperature and increased salinity resulting in increased density. NADW is the outflow of this thick deep layer, which can be detected by its high salinity, high oxygen content, nutrient minima, high C/C, and chlorofluorocarbons (CFCs).

CFCs are anthropogenic substances that enter the surface of the ocean from gas exchange with the atmosphere. This distinct composition allows its path to be traced as it mixes with Circumpolar Deep Water (CDW), which in turn fills the deep Indian Ocean and part of the South Pacific. NADW and its formation is essential to the Atlantic meridional overturning circulation (AMOC), which is responsible for transporting large amounts of water, heat, salt, carbon, nutrients and other substances from the Tropical Atlantic to the Mid and High Latitude Atlantic.

James Ephraim Lovelock (26 July 1919 – 26 July 2022) was an English independent scientist, environmentalist and futurist. He is best known for proposing the Gaia hypothesis, which postulates that the Earth functions as a self-regulating system.

With a PhD in the chemistry of disinfection, Lovelock began his career performing cryopreservation experiments on rodents, including successfully thawing and reviving frozen specimens. His methods were influential in the theories of cryonics (the cryopreservation of humans). He invented the electron capture detector and, using it, became the first to detect the widespread presence of chlorofluorocarbons in the atmosphere. While designing scientific instruments for NASA, he developed the Gaia hypothesis.

Dichlorodifluoromethane (R-12) is a colorless gas popularly known by the genericized brand name Freon (as Freon-12). It is a chlorofluorocarbon halomethane (CFC) used as a refrigerant and aerosol spray propellant. In compliance with the Montreal Protocol, its manufacture was banned in developed countries (non-article 5 countries) in 1996, and in developing countries (Article 5 countries) in 2010 out of concerns about its damaging effect on the ozone layer. Its only allowed usage is as a fire retardant in submarines and aircraft. It is soluble in many organic solvents. R-12 cylinders are colored white.

R-12 has the highest potential for ozone destruction of all refrigeration gases.

Freon (/ˈfriːɒn/ FREE-on) is a registered trademark of the Chemours Company and generic descriptor for a number of halocarbon products. They are stable, nonflammable, low toxicity gases or liquids which have generally been used as refrigerants and as aerosol propellants. They include chlorofluorocarbons (CFCs) and hydrofluorocarbons (HFCs), both of which cause ozone depletion (although the latter much less so) and contribute to global warming. "Freon" is the brand name for the refrigerants R-12, R-13B1, R-22, R-410A, R-502, and R-503 manufactured by the Chemours Company. They emit a strong smell similar to acetone. Freon has been found to cause damage to human health when inhaled in large amounts. Studies have been conducted in the pursuit to find beneficial reuses for gases under the Freon umbrella as an alternative to disposal.

Ozone depletion consists of two related events observed since the late 1970s: a lowered total amount of ozone in Earth's upper atmosphere, and a much larger springtime decrease in stratospheric ozone (the ozone layer) around Earth's polar regions. The latter phenomenon is referred to as the ozone hole. There are also springtime polar tropospheric ozone depletion events in addition to these stratospheric events.

The main causes of ozone depletion and the ozone hole are manufactured chemicals, especially manufactured halocarbon refrigerants, solvents, propellants, and foam-blowing agents (chlorofluorocarbons (CFCs), HCFCs, halons), referred to as ozone-depleting substances (ODS). These compounds are transported into the stratosphere by turbulent mixing after being emitted from the surface, mixing much faster than the molecules can settle. Once in the stratosphere, they release atoms from the halogen group through photodissociation, which catalyze the breakdown of ozone (O₃) into oxygen (O₂). Both types of ozone depletion were observed to increase as emissions of halocarbons increased.

Hydrofluoroolefins (HFOs) are unsaturated organic compounds composed of hydrogen, fluorine and carbon. These organofluorine compounds are of interest as refrigerants. Unlike traditional hydrofluorocarbons (HFCs) and chlorofluorocarbons (CFCs), which are saturated, HFOs are olefins, otherwise known as alkenes.

HFO refrigerants are categorized as having zero ozone depletion potential (ODP) and low global warming potential (GWP) and so offer a more environmentally friendly alternative to CFC, HCFC, and HFC refrigerants. Compared to HCFCs and HFCs, HFOs have shorter tropospheric lifetimes due to the reactivity of the C=C bond with hydroxyl radicals and chlorine radicals. This quick reactivity prevents them from reaching the stratosphere and participating in the depletion of good ozone, leading to strong interest in the development and characterization of new HFO blends for use as refrigerants. Many refrigerants in the HFO class are inherently stable chemically and inert, non toxic, and non-flammable or mildly flammable. Many HFOs have the proper freezing and boiling points to be useful for refrigeration at common temperatures. They have also been adopted as blowing agents, i.e. in production of insulation foams, food industry, construction materials, and others. However, HFOs degrade to produce trifluoroacetic acid, a persistent toxic chemical which can lead to acidification of water bodies, and which can accumulate in wetlands, a sensitive ecosystem.

DuPont de Nemours, Inc., commonly shortened to DuPont, is an American multinational chemical company first formed in 1802 by French-American chemist and industrialist Éleuthère Irénée du Pont de Nemours. The company played a major role in the development of the U.S. state of Delaware and first arose as a major supplier of gunpowder. DuPont developed many polymers such as Vespel, neoprene, nylon, Corian, Teflon, Mylar, Kapton, Kevlar, Zemdrain, M5 fiber, Nomex, Tyvek, Sorona, viton, Corfam and Lycra in the 20th century, and its scientists developed many chemicals, most notably Freon (chlorofluorocarbons), for the refrigerant industry. It also developed synthetic pigments and paints including ChromaFlair.

In 2015, DuPont and the Dow Chemical Company agreed to a reorganization plan in which the two companies would merge and split into three. As a merged entity, DuPont simultaneously acquired Dow and renamed itself to DowDuPont on August 31, 2017. After 18 months it spun off the merged entity's material science divisions into a new corporate entity bearing Dow Chemical's name and the agribusiness divisions into the newly created Corteva; DowDuPont reverted its name to DuPont and kept the specialty products divisions. Prior to the spinoffs it was the world's largest chemical company in terms of sales. The merger has been reported to be worth an estimated $130 billion.

1,1,2-Trichloro-1,2,2-trifluoroethane, also called simply trichlorotrifluoroethane (often abbreviated as TCTFE) or CFC-113, is a chlorofluorocarbon. It has the formula Cl₂FC−CClF₂. This colorless, volatile liquid was a versatile solvent used in various precise cleaning operations until it was phased out due its impact on the ozone layer.

1-Bromopropane (also known as n-propyl bromide or nPB) is a bromoalkane with the chemical formula CH₃CH₂CH₂Br. It is a colorless, flammable liquid that is used as a solvent. It has a characteristic hydrocarbon odor. Its industrial applications increased dramatically in the 21st century due to the phasing out of chlorofluorocarbons and chloroalkanes such as 1,1,1-trichloroethane under the Montreal Protocol. It was also used as a dry cleaning solvent as a substitute for perchloroethylene for a short time in the United States. 1-Bromopropane is highly neurotoxic to humans.