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COP27: a glossary of climate change terminology

Do you know the differences between scope one, two and three greenhouse gas emissions? Is it better to be net zero or climate positive? Our COP27 glossary will help you to understand the key terms

For out­siders try­ing to fol­low pro­ceed­ings at the annu­al Con­fer­ence of the Par­ties (COP) to the Unit­ed Nations Frame­work Con­ven­tion on Cli­mate Change, the sheer vol­ume of jar­gon used at this event rep­re­sents a sig­nif­i­cant bar­ri­er to under­stand­ing. Experts in this fast-evolv­ing field have coined hun­dreds of tech­ni­cal terms over the decades.

Some, such as cli­mate repa­ra­tions, are rel­a­tive­ly new, but old­er ones are still often mis­un­der­stood. Sev­er­al more – leak­age, for instance – mean some­thing dif­fer­ent from their ordi­nary def­i­n­i­tion.

Con­sid­er the three core themes of this year’s con­fer­ence – COP27, to be held in Sharm El Sheikh on 6–18 Novem­ber – for exam­ple. Host nation Egypt wants del­e­gates to focus on adap­ta­tion, mit­i­ga­tion and cli­mate finance. Each has a spe­cif­ic tech­ni­cal mean­ing in this con­text.

The fol­low­ing glos­sary explains these and oth­er cli­mate-relat­ed terms that sci­en­tists and pol­i­cy-mak­ers com­mon­ly use.

Adaptation

This is the process of mak­ing changes to pro­tect com­mu­ni­ties against the impacts of extreme and less pre­dictable weath­er that’s already result­ing from glob­al warm­ing. It can include mea­sures such as tak­ing out cli­mate insur­ance; alter­ing what crops are grown in an area; and build­ing infra­struc­ture such as flood defences.

Mitigation

This refers to efforts to low­er the vol­ume of green­house gas in the atmos­phere. It can involve either reduc­ing emis­sions – such as by using less fos­sil fuel and switch­ing to renew­able ener­gy sources – or enhanc­ing sinks that can remove gas­es from the air, includ­ing forests or arti­fi­cial car­bon-cap­ture sys­tems.

Climate finance

This refers to mon­ey set aside to fund mit­i­ga­tion and adap­ta­tion projects around the world. These rarely come cheap, of course. Even wealthy coun­tries will strug­gle to fund such mea­sures, let alone the many emerg­ing economies that are already expe­ri­enc­ing the most extreme weath­er.

Accord­ing to the Organ­i­sa­tion for Eco­nom­ic Co-oper­a­tion and Devel­op­ment, rich coun­tries com­mit­ted $83.3bn in 2020 to help poor­er nations deal with the “loss and dam­age” they had expe­ri­enced (break­ing an ear­li­er pledge to pro­vide £100bn a year by that point). Den­mark was the first coun­try to pledge spe­cif­ic com­pen­sa­tion to coun­tries most affect­ed by cli­mate change.

Climate glossary

1.5 degrees

A 1.5C lim­it on the rise in the Earth’s aver­age tem­per­a­ture above pre-indus­tri­al lev­els was enshrined in the UN’s 2015 Paris agree­ment. Pro­jec­tions from its Inter­gov­ern­men­tal Pan­el on Cli­mate Change (IPCC) sug­gest that increas­es above this lev­el would cause some of the worst effects of cli­mate change to become com­mon­place, putting bil­lions of peo­ple at risk and caus­ing irre­versible envi­ron­men­tal dam­age. Research indi­cates that the plan­et has already warmed by 1.1C, accord­ing to the IPCC.

Afforestation and reforestation

Refor­esta­tion means return­ing land that was pre­vi­ous­ly tree-cov­ered back to its orig­i­nal state. Afforesta­tion is the cre­ation of new wood­land. Both are wide­ly regard­ed as pow­er­ful mit­i­ga­tion mea­sures.

Anthropocene

The geo­log­i­cal his­to­ry of the Earth is divid­ed into epochs. The cur­rent epoch, the Holocene, began rough­ly 11,500 years ago at the end of an ice age. Some sci­en­tists have start­ed sug­gest­ing that humans have made such enor­mous changes to the plan­et over the past 60 years that it has entered a new epoch: the Anthro­pocene.

Biodiversity

The vari­ety of life on Earth, cov­er­ing species rang­ing from a bac­teri­um all the way up to a blue whale. This is in steep decline in sev­er­al ter­ri­to­ries. The UK, for instance, has lost about half of its bio­di­ver­si­ty in the mod­ern era, mak­ing it one of the most nature-deplet­ed coun­tries.

Biofuel

A fuel made from organ­ic mat­ter over a short time span (as opposed to the long-term process­es that cre­ate fos­sil fuels such as coal and gas). Bio­fu­el includes wood as well as bioethanol and biodiesel made from crops, waste oil and algae. Many emit rel­a­tive­ly few net green­house gas­es when burnt, but they can have oth­er neg­a­tive envi­ron­men­tal impacts.

Carbon border adjustment mechanism (CBAM)

The CBAM is an import tax on car­bon-inten­sive prod­ucts such as steel, alu­mini­um, cement and fer­tilis­er. It’s part of the EU’s strat­e­gy to cut its green­house gas emis­sions by at least 55% by 2030. The sys­tem is designed to lev­el the play­ing field for EU-based com­pa­nies, help­ing them to remain com­pet­i­tive with firms from juris­dic­tions that might not oper­ate to such strict tar­gets.

Carbon capture and storage

The process of cap­tur­ing, trans­port­ing and stor­ing car­bon diox­ide from a large emit­ting source, such as a pow­er plant or indus­tri­al facil­i­ty, before it enters the atmos­phere. The stor­age process, some­times referred to as seques­tra­tion, often involves inject­ing the CO2 deep under­ground.

Carbon capture and utilisation

A process of col­lect­ing car­bon diox­ide from one source and reusing it to pro­duce a new prod­uct. Although this process does­n’t remove car­bon from the atmos­phere, recy­cling the CO2 can turn a car­bon-inten­sive process into a car­bon-neu­tral one.

Carbon credits

Car­bon cred­its can be earned through off­set­ting, with each cer­ti­fied cred­it rep­re­sent­ing an emis­sions reduc­tion equiv­a­lent to one tonne of car­bon diox­ide. These cred­its can then be pur­chased by a com­pa­ny or coun­try to count towards its own car­bon-reduc­tion goals.

Carbon dioxide equivalent (CO2e)

A mea­sure­ment used to group green­house gas­es based on their warm­ing poten­tial. Using this mea­sure­ment helps to account for the emis­sions of all gas­es that con­tribute to the heat­ing of the plan­et, such as methane and nitrous oxide, by cal­cu­lat­ing the amount of car­bon diox­ide that would cause the same amount of warm­ing.

Carbon footprint

A car­bon foot­print can refer to the amount of car­bon emit­ted by a com­pa­ny over a giv­en peri­od, the life­time of a prod­uct or an individual’s actions — trav­el­ling by air, for instance.

Carbon intensity

The amount of car­bon diox­ide emit­ted per unit of elec­tric­i­ty gen­er­at­ed. Clean­er fuels have a low­er car­bon inten­si­ty. The term can also refer to the lev­el of emis­sions a coun­try or com­pa­ny pro­duces rel­a­tive to its eco­nom­ic out­put.

Carbon neutral

Becom­ing car­bon neu­tral can be achieved by remov­ing or elim­i­nat­ing the same amount of green­house gas emit­ted into the atmos­phere. This is also some­times referred to as being net zero.

Carbon offsetting

This refers to an organisation’s attempt to com­pen­sate for its car­bon diox­ide emis­sions by fund­ing efforts to remove the equiv­a­lent amount from the atmos­phere else­where. This often involves a third par­ty, which is paid to per­form the decar­bon­is­ing action in return for car­bon cred­its. Com­mon car­bon off­sets include plant­i­ng trees or fund­ing projects to gen­er­ate renew­able ener­gy. It is often used in areas of the econ­o­my that are hard to decar­bonise, such as air trav­el.

Carbon sequestration

The process of cap­tur­ing and stor­ing car­bon diox­ide from the atmos­phere and stor­ing it in a sol­id or liq­uid form (see car­bon cap­ture and stor­age). It is a method of reduc­ing or revers­ing the impact of CO2 pol­lu­tion and mit­i­gat­ing the effects of cli­mate change.

Certified emission reductions (CERs)

These are car­bon cred­its issued by the UN to coun­tries for projects that mit­i­gate green­house gas emis­sions. Coun­tries can trade CERs to help them meet their emis­sion reduc­tion goals. For exam­ple, Chi­na could buy cred­its earned by a refor­esta­tion project in Kenya and use these to off­set its own emis­sions.

Citizens’ assembly

A rep­re­sen­ta­tive group of lay peo­ple who gath­er to dis­cuss gov­ern­ment pol­i­cy in a par­tic­u­lar area and rec­om­mend new mea­sures. They have been used in Ire­land and Spain to address cli­mate change and are wide­ly pro­mot­ed by groups such as Extinc­tion Rebel­lion as a way to reach a con­sen­sus on solu­tions.

Climate justice

Cli­mate jus­tice is the recog­ni­tion that cli­mate change will not affect every­one equal­ly. Peo­ple who are young, poor, mar­gin­alised and liv­ing in devel­op­ing coun­tries are among those least respon­si­ble for the world’s green­house gas emis­sions, yet they will tend to feel the worst effects of glob­al warm­ing and cli­mate change.

Climate activists hold up a sign saying "There is no planet B"

Climate positive

Cli­mate pos­i­tive sta­tus is an improve­ment on net zero, in that the amount of car­bon diox­ide an enti­ty is remov­ing from the atmos­phere exceeds what it’s emit­ting.

Climate reparations

This is a key demand of the cli­mate jus­tice move­ment. Many argue that devel­oped coun­tries should pay nations in the Glob­al South to help them pre­pare for the worst con­se­quences of cli­mate change.

Climate tech

This term refers to advanced tech­nolo­gies that are being designed and devel­oped to help decar­bonise the glob­al econ­o­my. It’s often applied to star­tups in the field.

COP27

The 27th annu­al Con­fer­ence of the Par­ties to the Unit­ed Nations Frame­work Con­ven­tion on Cli­mate Change will be held on 6–18 Novem­ber. Cli­mate experts, cam­paign­ers and pol­i­cy-mak­ers will con­vene at Sharm El Sheikh, Egypt, to dis­cuss how best to avert the worst effects of cli­mate change.

Emissions trading scheme (ETS)

Also known as cap and trade, an emis­sions trad­ing scheme sets a lim­it on the max­i­mum amount of emis­sions and issues per­mits that com­pa­nies can buy or trade. This cre­ates a car­bon mar­ket with the aim of encour­ag­ing firms to reduce their emis­sions. The EU ETS is the world’s largest, while the UK has oper­at­ed its own scheme since Jan­u­ary 2021.

Energy charter treaty (ECT)

An inter­na­tion­al treaty signed in 1991 to pro­mote col­lab­o­ra­tion among coun­tries with a large stake in the ener­gy indus­try, espe­cial­ly the fos­sil fuels sec­tor. Because it allows investors to sue for lost prof­its owing to gov­ern­ment pol­i­cy changes, it has come under fire for obstruct­ing nation­al efforts to com­bat cli­mate change. Sev­er­al Euro­pean coun­tries – most recent­ly, France – have declared their inten­tion to pull out of the agree­ment.

Energy transition

The glob­al effort to move from fos­sil fuels and oth­er non-renew­ables to clean­er sources of ener­gy, such as wind, solar and green hydro­gen.

Greenwashing

This is the pejo­ra­tive term applied to a mar­ket­ing cam­paign that’s designed to draw atten­tion to an entity’s sus­tain­able prac­tices and, often, dis­tract from its more envi­ron­men­tal­ly dam­ag­ing behav­iour.

Greenhouse gases

These are com­pounds that con­tribute to glob­al warm­ing through the green­house effect when they are emit­ted into the atmos­phere. The Kyoto pro­to­col con­cerns the emis­sion of car­bon diox­ide, methane, nitrous oxide, sul­phur hexa­flu­o­ride and mem­bers of both the hydro­flu­o­ro­car­bon and per­flu­o­ro­car­bon groups.

Intergovernmental Panel on Climate Change

The IPCC is the UN’s body for pro­vid­ing sci­en­tif­ic assess­ments of cli­mate change. It was cre­at­ed to give pol­i­cy-mak­ers reg­u­lar updates on the impli­ca­tions and poten­tial future risks of cli­mate change and to sug­gest pos­si­ble adap­ta­tion and mit­i­ga­tion mea­sures. The pan­el’s most recent report was described as a “code red for human­i­ty” by the UN’s sec­re­tary-gen­er­al, António Guter­res.

Just transition

Many organ­i­sa­tions agree that it’s impor­tant for the ener­gy tran­si­tion to hap­pen in a way that is socioe­co­nom­i­cal­ly fair. For instance, coal min­ers left out of a job should be sup­port­ed to retrain and find new work. The EU has allo­cat­ed €150m (£131m) to its just tran­si­tion fund.

Kyoto protocol

Signed at COP3 in 1997, the Kyoto pro­to­col was an inter­na­tion­al treaty com­mit­ting all sig­na­to­ries to reduce the world’s green­house gas emis­sions. Com­ing into force in 2005, it was the first pact of its kind to set nation­al gov­ern­ments legal­ly bind­ing tar­gets. It was super­seded by the Paris agree­ment in 2015.

Leakage

While it sounds like it refers to gas or oil escap­ing a pipeline, leak­age has a spe­cif­ic mean­ing in envi­ron­men­tal terms. It hap­pens when one country’s cli­mate poli­cies result in high­er green­house gas emis­sions in anoth­er. For exam­ple, many west­ern coun­tries have reduced their car­bon foot­prints by mov­ing pol­lut­ing indus­tries abroad.

Loss and damage

The neg­a­tive effects expe­ri­enced as a result of cli­mate change. It has been claimed that some coun­tries have already lost a fifth of their wealth as a result of extreme weath­er, for exam­ple.

Natural capital

A way to describe the wealth a coun­try holds in terms of nat­ur­al resources such as fer­tile soil, fresh water, clean air and bio­di­verse habi­tat. It has been argued that this should be mea­sured, like GDP or finan­cial assets, to encour­age gov­ern­ments to con­serve nature.

Net zero

Net zero refers to the point at which the amount of green­house gas being emit­ted into the atmos­phere equates to the amount being removed.

Ocean acidification

A side effect of cli­mate change, in which the increas­ing absorp­tion of car­bon diox­ide by the world’s oceans is low­er­ing their pH. In oth­er words, they have become about 30% more acidic than they were in the pre-indus­tri­al era. This has dam­aged a wide range of marine ecosys­tems.

Paris agreement

A legal­ly bind­ing inter­na­tion­al treaty that was signed dur­ing COP21 in 2015. It set impor­tant goals to keep the rise in glob­al tem­per­a­tures below 2C and aim for less than 1.5C. It also set finan­cial tar­gets for devel­oped nations to help mit­i­gate the impacts of cli­mate change.

Rewilding

Return­ing ecosys­tems to their nat­ur­al state with­out human inter­ven­tion. It’s often achieved by rein­tro­duc­ing native species to an area, stop­ping wildlife culls and allow­ing forests to regen­er­ate on their own instead of plant­i­ng trees.

“Nature knows best when it comes to sur­vival and self-gov­er­nance,” argues the char­i­ty Rewil­d­ing Europe. “We should step back and let nature man­age itself.”

Scope one emissions

Scope one con­cerns the green­house gas­es emit­ted direct­ly by an enti­ty, such as those released as a result of a business’s indus­tri­al oper­a­tions.

Scope two

Scope two cov­ers an entity’s indi­rect emis­sions, often asso­ci­at­ed with the pro­duc­tion of gas and elec­tric­i­ty it pur­chas­es from an ener­gy sup­pli­er.

Scope three

Scope three cov­ers all emis­sions up and down the entity’s val­ue chain. For many busi­ness­es, this is the source of most of their emis­sions. Upstream emis­sions include those aris­ing from the pro­duc­tion of mate­ri­als pur­chased by the com­pa­ny, such as pack­ag­ing; the dis­tri­b­u­tion of fin­ished goods; and busi­ness trav­el by employ­ees. Down­stream emis­sions include those gen­er­at­ed by the use of its prod­ucts and their end-of-life treat­ment, as well as those of any leased assets, fran­chis­es or invest­ments.

Sink

Any­thing that absorbs more car­bon diox­ide than it emits, includ­ing the sea, soil and veg­e­ta­tion. In the future, it may be pos­si­ble to cre­ate arti­fi­cial sinks through the use of car­bon cap­ture and stor­age tech­nol­o­gy.

Tipping point

In cli­mate sci­ence, this is the sit­u­a­tion in which irre­versible changes will hap­pen and become self-per­pet­u­at­ing. Exam­ples include the col­lapse of the east Antarc­tic ice sheet and the loss of trop­i­cal coral reefs.

United Nations Framework Convention on Climate Change (UNFCCC)

This was a land­mark inter­na­tion­al treaty signed at the Earth sum­mit in Rio de Janeiro in 1992. It serves as the par­ent treaty to both the Kyoto pro­to­col and the Paris agree­ment. The UNFCCC is also the name of the sec­re­tari­at that sup­ports the treaty’s oper­a­tion. It is based in Bonn, Ger­many.

Warsaw international mechanism for loss and damage

Estab­lished at COP19 in 2013, this frame­work pro­motes dia­logue and research to address the effects of cli­mate change. It con­tains no pro­vi­sion for coun­tries to pay cli­mate repa­ra­tions.