Editing IPCC:AR6/Data/Glossary (section)

== I ==

<div class="glossary-entry">
<div id="Ice_age"></div>
=== <span class="glossary-term">Ice age</span> ===

<div class="glossary-working-groups">'''Working Groups:''' WGI</div>

<div class="glossary-definition">'''Definition:''' An informal term for a geological period characterized by a long-term reduction in the temperature of the Earth’s climate, resulting in the presence or expansion of ice sheets and glaciers. Among the Earth’s ice ages is the current Quaternary Period, characterized by alternating glacial and interglacial intervals.</div>
</div>

<div class="glossary-entry">
<div id="Icealbedo_feedback"></div>
=== <span class="glossary-term">Ice–albedo feedback</span> ===

<div class="glossary-working-groups">'''Working Groups:''' WGI</div>

<div class="glossary-definition">'''Definition:''' A climate feedback involving changes in the Earth’s surface albedo. Snow and ice have an albedo much higher (up to ~0.8) than the average planetary albedo (~0.3). With increasing temperatures, it is anticipated that snow and ice extent will decrease, the Earth’s overall albedo will decrease and more solar radiation will be absorbed, warming the Earth further.</div>
</div>

<div class="glossary-entry">
<div id="Ice_core"></div>
=== <span class="glossary-term">Ice core</span> ===

<div class="glossary-working-groups">'''Working Groups:''' WGI</div>

<div class="glossary-definition">'''Definition:''' A cylinder of ice drilled out of a glacier or ice sheet to determine the physical properties of the ice body and to gain information on past changes in climate and composition of the atmosphere that are preserved in the ice or in air trapped in the ice.</div>
</div>

<div class="glossary-entry">
<div id="Ice_sheet"></div>
=== <span class="glossary-term">Ice sheet</span> ===

<div class="glossary-working-groups">'''Working Groups:''' WGI; WGII</div>

<div class="glossary-definition">'''Definition:''' An ice body originating on land that covers an area of continental size, generally defined as covering >50,000 km 2, and that has formed over thousands of years through accumulation and compaction of snow. An ice sheet flows outward from a high central ice plateau with a small average surface slope. The margins usually slope more steeply, and most ice is discharged through fast-flowing ice streams or outlet glaciers, often into the sea or into ice shelves floating on the sea. There are only two ice sheets in the modern world, one on Greenland and one on Antarctica. The latter is divided into the East Antarctic Ice Sheet (EAIS), the West Antarctic Ice Sheet (WAIS) and the Antarctic Peninsula Ice Sheet. During glacial periods, there were other ice sheets.</div>
</div>

<div class="glossary-entry">
<div id="Ice_shelf"></div>
=== <span class="glossary-term">Ice shelf</span> ===

<div class="glossary-working-groups">'''Working Groups:''' WGI</div>

<div class="glossary-definition">'''Definition:''' A floating slab of ice originating from land of considerable thickness extending from the coast (usually of great horizontal extent with a very gently sloping surface), resulting from the flow of ice sheets, initially formed by the accumulation of snow, and often filling embayments in the coastline of an ice sheet. Nearly all ice shelves are in Antarctica, where most of the ice discharged into the ocean flows via ice shelves.</div>
</div>

<div class="glossary-entry">
<div id="Ice_stream"></div>
=== <span class="glossary-term">Ice stream</span> ===

<div class="glossary-working-groups">'''Working Groups:''' WGI</div>

<div class="glossary-definition">'''Definition:''' A stream of ice with strongly enhanced flow that is part of an ice sheet. It is often separated from surrounding ice by strongly sheared, crevassed margins.</div>
</div>

<div class="glossary-entry">
<div id="Iceberg"></div>
=== <span class="glossary-term">Iceberg</span> ===

<div class="glossary-working-groups">'''Working Groups:''' WGI</div>

<div class="glossary-definition">'''Definition:''' Large piece of freshwater ice broken off from a glacier or an ice shelf during calving and floating in open water (at least 5 m height above sea level). Smaller pieces of floating ice known as ‘bergy bits’ (less than 5 m above sea level) or ‘growlers’ (less than 2 m above sea level) can originate from glaciers or ice shelves, or from the breaking up of a large iceberg. Icebergs can also be classified by shape, most commonly being either tabular (steep sides and a flat top) or non-tabular (varying shapes, with domes and spires) (NOAA, 2021). In lakes, icebergs can originate by breaking off shelf ice, which forms through freezing of a lake surface.</div>
</div>

<div class="glossary-entry">
<div id="Impacts"></div>
=== <span class="glossary-term">Impacts</span> ===

<div class="glossary-working-groups">'''Working Groups:''' WGII; WGIII</div>

<div class="glossary-definition">'''Definition:''' The consequences of realised risks on natural and human systems, where risks result from the interactions of climate-related hazards (including extreme weather/climate events), exposure, and vulnerability. Impacts generally refer to effects on lives, livelihoods, health and well-being, ecosystems and species, economic, social and cultural assets, services (including ecosystem services), and infrastructure. Impacts may be referred to as consequences or outcomes, and can be adverse or beneficial.</div>
</div>

<div class="glossary-entry">
<div id="Income"></div>
=== <span class="glossary-term">Income</span> ===

<div class="glossary-working-groups">'''Working Groups:''' WGII</div>

<div class="glossary-definition">'''Definition:''' The maximum amount that a household, or other unit, can consume without reducing its real net worth. Total income is the broadest measure of income and refers to regular receipts such as wages and salaries, income from self-employment, interest and dividends from invested funds, pensions or other benefits from social insurance, and other current transfers receivable. OECD (2003).</div>
</div>

<div class="glossary-entry">
<div id="Incremental_adaptation"></div>
=== <span class="glossary-term">Incremental adaptation</span> ===

<div class="glossary-working-groups">'''Working Groups:''' WGII; WGIII</div>

<div class="glossary-definition">'''Definition:''' Adaptation that maintains the essence and integrity of a system or process at a given scale (Park et al., 2012). In some cases, incremental adaptation can accrue to result in transformational adaptation (Tàbara et al., 2019; Termeer et al., 2017). Incremental adaptations to change in climate are understood as extensions of actions and behaviours that already reduce the losses or enhance the benefits of natural variations in extreme weather/climate events.</div>
</div>

<div class="glossary-entry">
<div id="Indian_Ocean_Dipole"></div>
=== <span class="glossary-term">Indian Ocean Dipole</span> ===

<div class="glossary-working-groups">'''Working Groups:''' WGI</div>

<div class="glossary-longer-term">'''Full term:''' Indian Ocean Dipole (IOD)</div>

<div class="glossary-definition">'''Definition:''' A mode of interannual variability that features an east–west dipole of sea surface temperature anomalies in the tropical Indian Ocean. Its positive phase shows concurrent sea surface cooling off Sumatra and Java and warming off Somalia in the west, combined with anomalous surface easterlies along the equator, while the opposite anomalies are seen in the negative phase. The IOD typically develops in boreal summer and matures in boreal autumn and controls part of the rainfall interannual variability in Australia, South Eastern Asia and Eastern Africa. See Section AIV.2.4 in Annex IV of the AR6 WGI report. Wikipedia Page</div>
</div>

<div class="glossary-entry">
<div id="Indian_Ocean_basin_mode"></div>
=== <span class="glossary-term">Indian Ocean basin mode</span> ===

<div class="glossary-working-groups">'''Working Groups:''' WGI</div>

<div class="glossary-longer-term">'''Full term:''' Indian Ocean basin (IOB) mode</div>

<div class="glossary-definition">'''Definition:''' A mode of interannual variability characterized by a temporal alternation of basin-wide warming and cooling of the Indian Ocean sea surface. It mostly develops in response to El Niño–Southern Oscillation (ENSO), but often persists after ENSO’s equatorial eastern Pacific signal has dissipated. The IOB affects atmospheric circulation, temperature, and precipitation in South, South East, and East Asia as well as Africa, and modulates tropical cyclone activity in the north western Pacific. See Section AIV.2.4 in Annex IV of the AR6 WGI report.</div>
</div>

<div class="glossary-entry">
<div id="Indigenous_Peoples"></div>
=== <span class="glossary-term">Indigenous Peoples</span> ===

<div class="glossary-working-groups">'''Working Groups:''' WGII</div>

<div class="glossary-definition">'''Definition:''' Indigenous Peoples and Nations are those that, having a historical continuity with pre-invasion and pre-colonial societies that developed on their territories, consider themselves distinct from other sectors of the societies now prevailing on those territories, or parts of them. They form at present principally non-dominant sectors of society and are often determined to preserve, develop, and transmit to future generations their ancestral territories, and their ethnic identity, as the basis of their continued existence as peoples, in accordance with their own cultural patterns, social institutions and common law system. Cobo (1987).</div>
</div>

<div class="glossary-entry">
<div id="Indigenous_knowledge"></div>
=== <span class="glossary-term">Indigenous knowledge</span> ===

<div class="glossary-working-groups">'''Working Groups:''' WGII; WGIII</div>

<div class="glossary-longer-term">'''Full term:''' Indigenous knowledge (IK)</div>

<div class="glossary-definition">'''Definition:''' The understandings, skills and philosophies developed by societies with long histories of interaction with their natural surroundings. For many indigenous peoples, IK informs decision-making about fundamental aspects of life, from day-to-day activities to longer term actions. This knowledge is integral to cultural complexes, which also encompass language, systems of classification, resource use practices, social interactions, values, ritual and spirituality. These distinctive ways of knowing are important facets of the world’s cultural diversity (UNESCO, 2018).</div>
</div>

<div class="glossary-entry">
<div id="Indirect_emissions"></div>
=== <span class="glossary-term">Indirect emissions</span> ===

<div class="glossary-working-groups">'''Working Groups:''' WGIII</div>

<div class="glossary-definition">'''Definition:''' Emissions that are a consequence of the activities within well-defined boundaries of, for instance, a region, an economic sector, a company or process, but which occur outside the specified boundaries. For example, emissions are described as indirect if they relate to the use of heat but physically arise outside the boundaries of the heat user, or to electricity production but physically arise outside of the boundaries of the power supply sector.</div>
</div>

<div class="glossary-entry">
<div id="Indirect_land-use_change"></div>
=== <span class="glossary-term">Indirect land-use change</span> ===

<div class="glossary-working-groups">'''Working Groups:''' WGI; WGIII</div>

<div class="glossary-longer-term">'''Full term:''' Indirect land-use change (iLUC)</div>

<div class="glossary-definition">'''Definition:''' Land-use change outside the area of focus that occurs as a consequence of change in use or management of land within the area of focus, such as through market or policy drivers. For example, if agricultural land is diverted to biofuel production, forest clearance may occur elsewhere to replace the former agricultural production.</div>
</div>

<div class="glossary-entry">
<div id="Industrial_revolution"></div>
=== <span class="glossary-term">Industrial revolution</span> ===

<div class="glossary-working-groups">'''Working Groups:''' WGI; WGIII</div>

<div class="glossary-definition">'''Definition:''' A period of rapid industrial growth with far-reaching social and economic consequences, beginning in Britain during the second half of the 18th century and spreading to Europe and later to other countries including the United States. The invention of the steam engine was an important trigger of this development. The industrial revolution marks the beginning of a strong increase in the use of fossil fuels, initially coal, and hence emission of 2) carbon dioxide (CO.</div>
</div>

<div class="glossary-entry">
<div id="Inequality"></div>
=== <span class="glossary-term">Inequality</span> ===

<div class="glossary-working-groups">'''Working Groups:''' WGII; WGIII</div>

<div class="glossary-definition">'''Definition:''' Uneven opportunities and social positions, and processes of discrimination within a group or society, based on gender, class, ethnicity, age and (dis)ability, often produced by uneven development. Income inequality refers to gaps between the highest and lowest income earners within a country and between countries.</div>
</div>

<div class="glossary-entry">
<div id="Informal_settlement"></div>
=== <span class="glossary-term">Informal settlement</span> ===

<div class="glossary-working-groups">'''Working Groups:''' WGII</div>

<div class="glossary-definition">'''Definition:''' A term given to settlements or residential areas that by at least one criterion fall outside official rules and regulations. Most informal settlements have poor housing (with widespread use of temporary materials) and are developed on land that is occupied illegally with high levels of overcrowding. In most such settlements, provision for safe water, sanitation, drainage, paved roads and basic services is inadequate or lacking. The term ‘slum’ is often used for informal settlements, although it is misleading as many informal settlements develop into good quality residential areas, especially where governments support such development.</div>
</div>

<div class="glossary-entry">
<div id="Infrastructure"></div>
=== <span class="glossary-term">Infrastructure</span> ===

<div class="glossary-working-groups">'''Working Groups:''' WGII; WGIII</div>

<div class="glossary-definition">'''Definition:''' The designed and built set of physical systems and corresponding institutional arrangements that mediate between people, their communities and the broader environment to provide services that support economic growth, health, quality of life and safety (Chester, 2019; Dawson et al., 2018).</div>
</div>

<div class="glossary-entry">
<div id="Insolation"></div>
=== <span class="glossary-term">Insolation</span> ===

<div class="glossary-working-groups">'''Working Groups:''' WGI</div>

<div class="glossary-definition">'''Definition:''' The amount of solar radiation reaching the Earth by latitude and by season measured in W m –2. Usually, insolation refers to the radiation arriving at the top of the atmosphere. Sometimes it is specified as referring to the radiation arriving at the Earth’s surface.</div>
</div>

<div class="glossary-entry">
<div id="Instantaneous_radiative_forcing_due_to_aerosolcloud_interactions"></div>
=== <span class="glossary-term">Instantaneous radiative forcing due to aerosol–cloud interactions</span> ===

<div class="glossary-working-groups">'''Working Groups:''' WGI</div>

<div class="glossary-longer-term">'''Full term:''' Instantaneous radiative forcing (or effect) due to aerosol–cloud interactions (IRFaci)</div>

<div class="glossary-definition">'''Definition:''' The radiative forcing (or radiative effect, if the perturbation is internally generated) due to the change in number or size distribution of cloud droplets or ice crystals that is the proximate result of an aerosol perturbation, with other variables (in particular total cloud water content) remaining equal. In liquid clouds, an increase in cloud droplet concentration and surface area would increase the cloud albedo. This effect is also known as the cloud albedo effect, first indirect effect, or Twomey effect. It is a largely theoretical concept that cannot readily be isolated in observations or comprehensive process models due to the ubiquity of adjustments.</div>
</div>

<div class="glossary-entry">
<div id="Instantaneous_radiative_forcing_due_to_aerosolradiation_interactions"></div>
=== <span class="glossary-term">Instantaneous radiative forcing due to aerosol–radiation interactions</span> ===

<div class="glossary-working-groups">'''Working Groups:''' WGI</div>

<div class="glossary-longer-term">'''Full term:''' Instantaneous radiative forcing (or effect) due to aerosol–radiation interactions (IRFari)</div>

<div class="glossary-definition">'''Definition:''' The radiative forcing (or radiative effect, if the perturbation is internally generated) of an aerosol perturbation due directly to aerosol–radiation interactions, with all environmental variables remaining unaffected. Traditionally known in the literature as the direct aerosol forcing (or effect).</div>
</div>

<div class="glossary-entry">
<div id="Institutional_capacity"></div>
=== <span class="glossary-term">Institutional capacity</span> ===

<div class="glossary-working-groups">'''Working Groups:''' WGII; WGIII</div>

<div class="glossary-definition">'''Definition:''' Building and strengthening individual organisations and providing technical and management training to support integrated planning and decision-making processes between organisations and people, as well as empowerment, social capital, and an enabling environment, including culture, values and power relations (Willems and Baumert, 2003).</div>
</div>

<div class="glossary-entry">
<div id="Institutions"></div>
=== <span class="glossary-term">Institutions</span> ===

<div class="glossary-working-groups">'''Working Groups:''' WGII; WGIII</div>

<div class="glossary-definition">'''Definition:''' Rules, norms and conventions that guide, constrain or enable human behaviours and practices. Institutions can be formally established, for instance through laws and regulations, or informally established, for instance by traditions or customs. Institutions may spur, hinder, strengthen, weaken or distort the emergence, adoption and implementation of climate action and climate governance. [Note: Institutions can also refer to a large organisation.]</div>
</div>

<div class="glossary-entry">
<div id="Insurance_reinsurance"></div>
=== <span class="glossary-term">Insurance/reinsurance</span> ===

<div class="glossary-working-groups">'''Working Groups:''' WGII</div>

<div class="glossary-definition">'''Definition:''' A family of financial instruments for sharing and transferring risk among a pool of at-risk households, businesses and/or governments.</div>
</div>

<div class="glossary-entry">
<div id="Integrated_assessment"></div>
=== <span class="glossary-term">Integrated assessment</span> ===

<div class="glossary-working-groups">'''Working Groups:''' WGII; WGIII</div>

<div class="glossary-definition">'''Definition:''' A method of analysis that combines results and models from the physical, biological, economic and social sciences and the interactions among these components in a consistent framework to evaluate the status and consequences of environmental change and the policy responses to it.</div>
</div>

<div class="glossary-entry">
<div id="Integrated_assessment_model"></div>
=== <span class="glossary-term">Integrated assessment model</span> ===

<div class="glossary-working-groups">'''Working Groups:''' WGI; WGII; WGIII</div>

<div class="glossary-longer-term">'''Full term:''' Integrated assessment model (IAM)</div>

<div class="glossary-definition">'''Definition:''' Models that integrate knowledge from two or more domains into a single framework. They are one of the main tools for undertaking integrated assessments. One class of IAM used with respect to climate change mitigation may include representations of: multiple sectors of the economy, such as energy, land use and land-use change; interactions between sectors; the economy as a whole; associated greenhouse gas (GHG) emissions and sinks; and reduced representations of the climate system. This class of model is used to assess linkages between economic, social and technological development and the evolution of the climate system. Another class of IAM additionally includes representations of the costs associated with climate change impacts, but includes less detailed representations of economic systems. These can be used to assess impacts and mitigation in a cost–benefit framework and have been used to estimate the social cost of carbon.</div>
</div>

<div class="glossary-entry">
<div id="Integrated_assessment_scenario_ensemble"></div>
=== <span class="glossary-term">Integrated assessment scenario ensemble</span> ===

<div class="glossary-working-groups">'''Working Groups:''' WGIII</div>

<div class="glossary-definition">'''Definition:''' A set of modelled scenarios from an intercomparison of integrated assessment models (IAMs) based on a systematic variation of harmonised scenario designs.</div>
</div>

<div class="glossary-entry">
<div id="Inter-decadal_Pacific_Oscillation"></div>
=== <span class="glossary-term">Inter-decadal Pacific Oscillation</span> ===

<div class="glossary-working-groups">'''Working Groups:''' WGI</div>

<div class="glossary-longer-term">'''Full term:''' Inter-decadal Pacific Oscillation (IPO)</div>

<div class="glossary-definition">'''Definition:''' An equatorially symmetric pattern of sea surface temperature variability at decadal-to-inter-decadal time scales. While the Pacific Decadal Oscillation (PDO) and its South Pacific counterpart, the South Pacific Decadal Oscillation (SPDO), are considered as physically distinct modes, the tropical Pacific decadal–inter-decadal variability can drive both the PDO and SPDO, forming the IPO as a synchronized pan-Pacific variability. Its spatial pattern of sea surface temperature anomalies is similar to that of the El Niño–Southern Oscillation (ENSO), but with a broader meridional extent in the tropical signal and more weights in the extratropics compared to the tropics. In the AR6 WGI report, it is encapsulated within the definition and description of Pacific Decadal Variability (PDV). See also Section AIV.2.6 in Annex IV of the AR6 WGI report.</div>
</div>

<div class="glossary-entry">
<div id="Inter-tropical_Convergence_Zone"></div>
=== <span class="glossary-term">Inter-tropical Convergence Zone</span> ===

<div class="glossary-working-groups">'''Working Groups:''' WGI</div>

<div class="glossary-longer-term">'''Full term:''' Inter-tropical Convergence Zone (ITCZ)</div>

<div class="glossary-definition">'''Definition:''' The Inter-tropical Convergence Zone is an equatorial zonal belt of low pressure, strong convection and heavy precipitation near the equator where the north-east trade winds meet the south-east trade winds. This band moves seasonally.</div>
</div>

<div class="glossary-entry">
<div id="Interglacial_or_interglaciation"></div>
=== <span class="glossary-term">Interglacial or interglaciation</span> ===

<div class="glossary-working-groups">'''Working Groups:''' WGI</div>

<div class="glossary-definition">'''Definition:''' A globally warm period lasting thousands of years between glacial periods within an ice age. Generally coincides with odd-numbered marine isotope stages (MIS) when mean sea level was close to present. The Last Interglacial (LIG) occurred between about 129 and 116 ka (thousand years) before present (defined as 1950) although the warm period started in some areas a few thousand years earlier. In terms of MIS, interglaciations are defined as the interval between the midpoint of the preceding termination and the onset of the next glaciation. The LIG coincides with MIS 5e. The present interglaciation, the Holocene, started at 11,700 years before 2000 CE, although global mean sea level did not approach its present position until roughly 7000 years ago.</div>
</div>

<div class="glossary-entry">
<div id="Internal_climate_variability"></div>
=== <span class="glossary-term">Internal climate variability</span> ===

<div class="glossary-working-groups">'''Working Groups:''' WGI</div>

<div class="glossary-definition">'''Definition:''' Deviations of climate variables from a given mean state (including the occurrence of extremes, etc.) at all spatial and temporal scales beyond that of individual weather events. Variability may be intrinsic, due to fluctuations of processes internal to the climate system.</div>
</div>

<div class="glossary-entry">
<div id="Internal_variability"></div>
=== <span class="glossary-term">Internal variability</span> ===

<div class="glossary-working-groups">'''Working Groups:''' WGI</div>

<div class="glossary-definition">'''Definition:''' Fluctuations of the climate dynamical system when subject to a constant or periodic external forcing (such as the annual cycle).</div>
</div>

<div class="glossary-entry">
<div id="Internet_of_Things"></div>
=== <span class="glossary-term">Internet of Things</span> ===

<div class="glossary-working-groups">'''Working Groups:''' WGIII</div>

<div class="glossary-longer-term">'''Full term:''' Internet of Things (IoT)</div>

<div class="glossary-definition">'''Definition:''' The network of computing devices embedded in everyday objects such as cars, phones and computers, connected via the internet, enabling them to send and receive data.</div>
</div>

<div class="glossary-entry">
<div id="Interpolation_uncertainty"></div>
=== <span class="glossary-term">Interpolation uncertainty</span> ===

<div class="glossary-working-groups">'''Working Groups:''' WGI</div>

<div class="glossary-definition">'''Definition:''' Uncertainty arising from a statistical or physical model-based interpolation of a field between available estimates to create a more spatio-temporally complete estimate.</div>
</div>

<div class="glossary-entry">
<div id="Interstadial_or_interstade"></div>
=== <span class="glossary-term">Interstadial or interstade</span> ===

<div class="glossary-working-groups">'''Working Groups:''' WGI</div>

<div class="glossary-definition">'''Definition:''' A brief period of regional climatic warming during a glacial or interglacial interval, often characterized by transient glacial retreats. Interstadials are generally of short duration (hundreds to a few thousand years) compared to glacial or interglacial intervals (lasting many thousands to tens of thousands of years). One example of a regional interstadial event is based on millennial scale warming recorded by oxygen isotope ratios in Greenland ice cores, the so called “Greenland Interstadials” (Johnsen et al., 1992).</div>
</div>

<div class="glossary-entry">
<div id="Invasive_species"></div>
=== <span class="glossary-term">Invasive species</span> ===

<div class="glossary-working-groups">'''Working Groups:''' WGII</div>

<div class="glossary-definition">'''Definition:''' A species that is not native to a specific location or nearby, lacking natural controls, and that has a tendency to rapidly increase in abundance, displacing native species. Invasive species may also damage the human economy or human health.</div>
</div>

<div class="glossary-entry">
<div id="Irreversibility"></div>
=== <span class="glossary-term">Irreversibility</span> ===

<div class="glossary-working-groups">'''Working Groups:''' WGI; WGIII</div>

<div class="glossary-definition">'''Definition:''' A perturbed state of a dynamical system is defined as irreversible on a given time scale if the recovery from this state due to natural processes takes substantially longer than the time scale of interest.</div>
</div>

<div class="glossary-entry">
<div id="Isostatic_or_Isostasy"></div>
=== <span class="glossary-term">Isostatic or Isostasy</span> ===

<div class="glossary-working-groups">'''Working Groups:''' WGI</div>

<div class="glossary-definition">'''Definition:''' Isostasy refers to the response of the Earth to changes in surface load. It includes the deformational and gravitational response. This response is elastic on short time scales, as in the Earth– ocean response to recent changes in mountain glaciation, or viscoelastic on longer time scales, as in the response to the last deglaciation following the Last Glacial Maximum.</div>
</div>

<div class="glossary-entry">
<div id="Isotopes"></div>
=== <span class="glossary-term">Isotopes</span> ===

<div class="glossary-working-groups">'''Working Groups:''' WGI</div>

<div class="glossary-definition">'''Definition:''' Atoms of the same chemical element that have the same the number of protons but differ in the number of neutrons. Some proton–neutron configurations are stable (stable isotopes), others are unstable undergoing spontaneous radioactive decay (radioisotopes). Most elements have more than one stable isotope. Isotopes can be used to trace transport processes or to study processes that change the isotopic ratio. Radioisotopes provide, in addition, time information that can be used for radiometric dating.</div>
</div>

</div>
<div class="glossary-letter-section">