Greenhouse gas monitoring is the direct

measurement Measurement is the quantification of attributes of an object or event, which can be used to compare with other objects or events. In other words, measurement is a process of determining how large or small a physical quantity is as compared ...

greenhouse gas emissions Greenhouse gas emissions from human activities strengthen the greenhouse effect, contributing to climate change. Most is carbon dioxide from burning fossil fuels: coal, oil, and natural gas. The largest emitters include coal in China and lar ...

and levels. There are several different methods of measuring carbon dioxide concentrations in the

atmosphere An atmosphere () is a layer of gas or layers of gases that envelop a planet, and is held in place by the gravity of the planetary body. A planet retains an atmosphere when the gravity is great and the temperature of the atmosphere is low. A s ...

, including infrared analyzing and manometry.

Methane Methane ( , ) is a chemical compound with the chemical formula (one carbon atom bonded to four hydrogen atoms). It is a group-14 hydride, the simplest alkane, and the main constituent of natural gas. The relative abundance of methane on Eart ...

and

nitrous oxide Nitrous oxide (dinitrogen oxide or dinitrogen monoxide), commonly known as laughing gas, nitrous, or nos, is a chemical compound, an oxide of nitrogen with the formula . At room temperature, it is a colourless non-flammable gas, and has a ...

are measured by other instruments. Greenhouse gases are measured from space such as by the

Orbiting Carbon Observatory The Orbiting Carbon Observatory (OCO) is a NASA satellite mission intended to provide global space-based observations of atmospheric carbon dioxide (). The original spacecraft was lost in a launch failure on 24 February 2009, when the payload f ...

and networks of

ground station A ground station, Earth station, or Earth terminal is a terrestrial radio station designed for extraplanetary telecommunication with spacecraft (constituting part of the ground segment of the spacecraft system), or reception of radio waves fro ...

s such as the

Integrated Carbon Observation System The Integrated Carbon Observation System (ICOS) is a research infrastructure to quantify the greenhouse gas balance of Europe and adjacent regions. In November 2015 it received the international legal status of ERIC (European Research Infrastruct ...

Methodology

Carbon dioxide monitoring

Manometry

Manometry is a key measurement tool for atmospheric

carbon dioxide Carbon dioxide (chemical formula ) is a chemical compound made up of molecules that each have one carbon atom covalently double bonded to two oxygen atoms. It is found in the gas state at room temperature. In the air, carbon dioxide is transpar ...

by first measuring the volume, temperature, and pressure of a particular amount of dry air. The air sample is dried by passing it through multiple

dry ice Dry ice is the solid form of carbon dioxide. It is commonly used for temporary refrigeration as CO2 does not have a liquid state at normal atmospheric pressure and sublimates directly from the solid state to the gas state. It is used primarily ...

traps and then collecting it in a five-liter vessel. The temperature is taken via a thermometer and pressure is calculated using manometry. Then,

liquid nitrogen Liquid nitrogen—LN2—is nitrogen in a liquid state at low temperature. Liquid nitrogen has a boiling point of about . It is produced industrially by fractional distillation of liquid air. It is a colorless, low viscosity liquid that is wide ...

is added, causing the

to condense and become measurable by volume. The

ideal gas law The ideal gas law, also called the general gas equation, is the equation of state of a hypothetical ideal gas. It is a good approximation of the behavior of many gases under many conditions, although it has several limitations. It was first stat ...

is accurate to 0.3% in these pressure conditions.

Infrared gas analyzer

Infrared analyzers were used at

Mauna Loa Observatory The Mauna Loa Observatory (MLO) is an atmospheric baseline station on Mauna Loa, on the island of Hawaii, located in the U.S. state of Hawaii. The observatory Since 1958, initially under the direction of Charles Keeling, followed by his s ...

and at Scripps Institution of Oceanography between 1958 and 2006. IR analyzers operate by pumping an unknown sample of dry air through a 40 cm long cell. A reference cell contains dry

-free air. A glowing nichrome filament radiates broadband IR radiation which splits into two beams and passes through the gas cells.

Carbon dioxide Carbon dioxide (chemical formula ) is a chemical compound made up of molecules that each have one carbon atom covalently double bonded to two oxygen atoms. It is found in the gas state at room temperature. In the air, carbon dioxide is transpar ...

absorbs some of the

radiation In physics, radiation is the emission or transmission of energy in the form of waves or particles through space or through a material medium. This includes: * ''electromagnetic radiation'', such as radio waves, microwaves, infrared, visi ...

, allowing more radiation that passes through the reference cell to reach the detector than radiation passing through the sample cell. Data is collected on a strip chart recorder. The concentration of

in the sample is quantified by calibrating with a standard gas of known

content.

Titrimetry

Titrimetry Titration (also known as titrimetry and volumetric analysis) is a common laboratory method of quantitative chemical analysis to determine the concentration of an identified analyte (a substance to be analyzed). A reagent, termed the ''titrant'' ...

is another method of measuring atmospheric

that was first used by a Scandinavian group at 15 different ground stations. They began passing a 100.0 mL air sample through a solution of

barium hydroxide Barium hydroxide is a chemical compound with the chemical formula Ba(OH)2. The monohydrate (''x'' = 1), known as baryta or baryta-water, is one of the principal compounds of barium. This white granular monohydrate is the usual commercial form. ...

containing

cresolphthalein ''o''-Cresolphthalein is a phthalein dye used as a pH indicator in titrations. It is insoluble in water but soluble in ethanol. Its solution is colourless below pH 8.2, and purple above 9.8. Its molecular formula is C22H18O4. It is used medically ...

indicator.

Methane gas monitoring

Differential absorption lidar

Range-resolved infrared

differential absorption lidar Lidar (, also LIDAR, or LiDAR; sometimes LADAR) is a method for determining ranges (variable distance) by targeting an object or a surface with a laser and measuring the time for the reflected light to return to the receiver. It can also be ...

(DIAL) is a means of measuring

methane emissions Increasing methane emissions are a major contributor to the rising concentration of greenhouse gases in Earth's atmosphere, and are responsible for up to one-third of near-term global heating. During 2019, about 60% (360 million tons) of methane r ...

from various sources, including active and closed landfill sites. The DIAL takes vertical scans above

methane Methane ( , ) is a chemical compound with the chemical formula (one carbon atom bonded to four hydrogen atoms). It is a group-14 hydride, the simplest alkane, and the main constituent of natural gas. The relative abundance of methane on Eart ...

sources and then spatially separates the scans to accurately measure the

from individual sources. Measuring

is a crucial aspect of

climate change research The history of the scientific discovery of climate change began in the early 19th century when ice ages and other natural changes in paleoclimate were first suspected and the natural greenhouse effect was first identified. In the late 19th cent ...

, as methane is among the most impactful gaseous

hydrocarbon In organic chemistry, a hydrocarbon is an organic compound consisting entirely of hydrogen and carbon. Hydrocarbons are examples of group 14 hydrides. Hydrocarbons are generally colourless and hydrophobic, and their odors are usually weak or ex ...

species.

Nitrous oxide monitoring

Atmospheric Chemistry Experiment‐Fourier Transform Spectrometer (ACE-FTS)

Nitrous oxide Nitrous oxide (dinitrogen oxide or dinitrogen monoxide), commonly known as laughing gas, nitrous, or nos, is a chemical compound, an oxide of nitrogen with the formula . At room temperature, it is a colourless non-flammable gas, and has a ...

is one of the most prominent

anthropogenic Anthropogenic ("human" + "generating") is an adjective that may refer to: * Anthropogeny, the study of the origins of humanity Counterintuitively, anthropogenic may also refer to things that have been generated by humans, as follows: * Human im ...

ozone-depleting gases in the atmosphere. It is released into the atmosphere primarily through natural sources such as soil and rock, as well as

process like farming. Atmospheric

is also created in the atmosphere as a product of a reaction between nitrogen and electronically excited

ozone Ozone (), or trioxygen, is an inorganic molecule with the chemical formula . It is a pale blue gas with a distinctively pungent smell. It is an allotrope of oxygen that is much less stable than the diatomic allotrope , breaking down in the lo ...

in the lower

thermosphere The thermosphere is the layer in the Earth's atmosphere directly above the mesosphere and below the exosphere. Within this layer of the atmosphere, ultraviolet radiation causes photoionization/photodissociation of molecules, creating ions; the ...

. The Atmospheric Chemistry Experiment‐Fourier Transform Spectrometer ( ACE-FTS) is a tool used for measuring

concentrations in the upper to lower

troposphere The troposphere is the first and lowest layer of the atmosphere of the Earth, and contains 75% of the total mass of the planetary atmosphere, 99% of the total mass of water vapour and aerosols, and is where most weather phenomena occur. From ...

. This instrument, which is attached to the Canadian satellite SCISAT, has shown that

is present throughout the entire atmosphere during all seasons, primarily due to energetic particle precipitation. Measurements taken by the instrument show that different reactions create

in the lower thermosphere than in the mid to upper mesosphere. The ACE-FTS is a crucial resource in predicting future

ozone depletion Ozone depletion consists of two related events observed since the late 1970s: a steady lowering of about four percent in the total amount of ozone in Earth's atmosphere, and a much larger springtime decrease in stratospheric ozone (the ozone l ...

in the upper stratosphere by comparing the different ways in which

is released into the atmosphere.

Satellite monitoring

Orbiting Carbon Observatory (OCO, OCO-2, OCO-3)

The

(OCO) was first launched in February 2009 but was lost due to launch failure. The

Satellite A satellite or artificial satellite is an object intentionally placed into orbit in outer space. Except for passive satellites, most satellites have an electricity generation system for equipment on board, such as solar panels or radioisotope ...

was launched again in 2014, this time called the

Orbiting Carbon Observatory-2 Orbiting Carbon Observatory-2 (OCO-2) is an American environmental science satellite which launched on 2 July 2014. A NASA mission, it is a replacement for the Orbiting Carbon Observatory which was lost in a launch failure in 2009. It is the seco ...

, with an estimated lifespan of about two years. The apparatus uses

spectrometer A spectrometer () is a scientific instrument used to separate and measure spectral components of a physical phenomenon. Spectrometer is a broad term often used to describe instruments that measure a continuous variable of a phenomenon where the ...

s to take 24

concentration measurements per second of

Earth's atmosphere The atmosphere of Earth is the layer of gases, known collectively as air, retained by Earth's gravity that surrounds the planet and forms its planetary atmosphere. The atmosphere of Earth protects life on Earth by creating pressure allowing for ...

. The measurements taken by

OCO-2 Orbiting Carbon Observatory-2 (OCO-2) is an American environmental science satellite which launched on 2 July 2014. A NASA mission, it is a replacement for the Orbiting Carbon Observatory which was lost in a launch failure in 2009. It is the seco ...

can be used for global atmospheric models and will allow scientists to locate

carbon source The molecules that an organism uses as its carbon source for generating biomass are referred to as "carbon sources" in biology. It's possible for a organic or inorganic sources of carbon. Heterotrophs must use organic molecules as both a source of ...

s when its data is paired with wind patterns. The Orbiting Carbon Observatory-3 operates from the

International Space Station The International Space Station (ISS) is the largest modular space station currently in low Earth orbit. It is a multinational collaborative project involving five participating space agencies: NASA (United States), Roscosmos (Russia), JAXA ...

(ISS).

Greenhouse Gases Observing Satellite (GOSat)

observations provides accurate readings of carbon dioxide and methane

gas Gas is one of the four fundamental states of matter (the others being solid, liquid, and plasma). A pure gas may be made up of individual atoms (e.g. a noble gas like neon), elemental molecules made from one type of atom (e.g. oxygen), or ...

concentrations for short-term and long-term purposes in order to detect changes over time. The goals of this

satellite A satellite or artificial satellite is an object intentionally placed into orbit in outer space. Except for passive satellites, most satellites have an electricity generation system for equipment on board, such as solar panels or radioisotope ...

, released in January 2009, is to monitor both

and

methane gas Methane ( , ) is a chemical compound with the chemical formula (one carbon atom bonded to four hydrogen atoms). It is a group-14 hydride, the simplest alkane, and the main constituent of natural gas. The relative abundance of methane on Ear ...

in the atmosphere, and to identify their sources.

GOSat The Greenhouse Gases Observing Satellite (GOSAT''), also known as , is an Earth observation satellite and the world's first satellite dedicated to greenhouse gas monitoring. It measures the densities of carbon dioxide and methane from 56,000 loc ...

is a project of three main entities: the

Japan Aerospace Exploration Agency The is the Japanese national air and space agency. Through the merger of three previously independent organizations, JAXA was formed on 1 October 2003. JAXA is responsible for research, technology development and launch of satellites into orb ...

(JAXA), the Ministry of the Environment (MOE), and the

National Institute for Environmental Studies The National Institute for Environmental Studies (''NIES'':国立環境研究所, Kokuritsu-Kankyō kenkyūsho) was established in 1974 as a focal point for environmental research in Japan. In 2001 it became an Independent Administrative Institut ...

(NIES).

Ground stations

Integrated Carbon Observation System (ICOS)

The Integrated Carbon Observation System was established in October 2015 in

Helsinki, Finland Helsinki ( or ; ; sv, Helsingfors, ) is the capital, primate, and most populous city of Finland. Located on the shore of the Gulf of Finland, it is the seat of the region of Uusimaa in southern Finland, and has a population of . The city' ...

as a European Research Infrastructure Consortium (ERIC). The main task of

ICOS Icos Corporation (trademark ICOS) was an American biotechnology company and the largest biotechnology company in the U.S. state of Washington, before it was sold to Eli Lilly and Company in 2007. It was founded in 1989 by David Blech, Isaac ...

is to establish an Integrated Carbon Observation System Research Infrastructure (ICOS RI) that facilitates research on

, sinks, and their causes. The ICOS ERIC strives to link its own research with other

research to produce coherent

data In the pursuit of knowledge, data (; ) is a collection of discrete values that convey information, describing quantity, quality, fact, statistics, other basic units of meaning, or simply sequences of symbols that may be further interpreted ...

products and to promote

education Education is a purposeful activity directed at achieving certain aims, such as transmitting knowledge or fostering skills and character traits. These aims may include the development of understanding, rationality, kindness, and honesty. Va ...

and

innovation Innovation is the practical implementation of ideas that result in the introduction of new goods or services or improvement in offering goods or services. ISO TC 279 in the standard ISO 56000:2020 defines innovation as "a new or changed entity ...

External links

Climate Trace
Public GHG monitoring expected from mid-2021

References

{{reflist Environmental science Environmental monitoring Greenhouse gas emissions Carbon dioxide Methane