Carbon budget#Recent and currently remaining carbon budget

The IPCC Sixth Assessment Reports defines carbon budget as the following two concepts:IPCC, 2021: [https://www.ipcc.ch/report/ar6/wg1/downloads/report/IPCC_AR6_WGI_AnnexVII.pdf Annex VII: Glossary] [Matthews, J.B.R., V. Möller, R. van Diemen, J.S. Fuglestvedt, V. Masson-Delmotte, C.  Méndez, S. Semenov, A. Reisinger (eds.)]. In [https://www.ipcc.ch/report/ar6/wg1/ Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change] [Masson-Delmotte, V., P. Zhai, A. Pirani, S.L. Connors, C. Péan, S. Berger, N. Caud, Y. Chen, L. Goldfarb, M.I. Gomis, M. Huang, K. Leitzell, E. Lonnoy, J.B.R. Matthews, T.K. Maycock, T. Waterfield, O. Yelekçi, R. Yu, and B. Zhou (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, pp. 2215–2256, {{doi|10.1017/9781009157896.022}}{{rp|2220}}

• "An assessment of carbon cycle sources and sinks on a global level, through the synthesis of evidence for fossil fuel and cement emissions, emissions and removals associated with land use and land-use change, ocean and natural land sources and sinks of carbon dioxide (CO₂), and the resulting change in atmospheric CO₂ concentration. This is referred to as the global carbon budget."; or
• "The maximum amount of cumulative net global anthropogenic CO₂ emissions that would result in limiting global warming to a given level with a given probability, taking into account the effect of other anthropogenic climate forcers. This is referred to as the total carbon budget when expressed starting from the pre-industrial period, and as the remaining carbon budget when expressed from a recent specified date."

Global carbon budgets can be further divided into national emissions budgets, so that countries can set specific climate mitigation goals.

An emissions budget may be distinguished from an emissions target, as an emissions target may be internationally or nationally set in accordance with objectives other than a specific global temperature and are commonly applied to the annual emissions in a single year as well.

{{See also|Tipping points in the climate system|Climate sensitivity|Carbon monitoring}}

Several organisations provide annual updates to the remaining carbon budget, including the Global Carbon Project, the Mercator Research Institute on Global Commons and Climate Change (MCC){{cite web |title=Remaining carbon budget - Mercator Research Institute on Global Commons and Climate Change (MCC) |url=https://www.mcc-berlin.net/en/research/co2-budget.html |website=www.mcc-berlin.net |access-date=27 April 2022}} and the CONSTRAIN project.{{Cite web |title=Publications {{!}} Reports Archives |url=https://constrain-eu.org/publications/type/reports/ |access-date=2023-09-20 |website=Constrain |language=en}} In March 2022, before formal publication of the "Global Carbon Budget 2021" preprint,{{cite journal |last1=Friedlingstein |first1=Pierre |last2=Jones |first2=Matthew W. |last3=O'Sullivan |first3=Michael |display-authors=et al. |title=Global Carbon Budget 2021 |journal=Earth System Science Data |date=26 April 2022|volume=14 |issue=4 |pages=1917–2005 |doi=10.5194/essd-14-1917-2022 |bibcode=2022ESSD...14.1917F |language=English |issn=1866-3508 |doi-access=free |hdl=20.500.11850/545754 |hdl-access=free }}

• News report: {{cite news |title=Cut emissions "starting now" – Global Carbon Project experts |url=https://www.exeter.ac.uk/news/research/title_909259_en.html |access-date=12 May 2022 |work=University of Exeter |language=en |archive-date=12 May 2022 |archive-url=https://web.archive.org/web/20220512104339/https://www.exeter.ac.uk/news/research/title_909259_en.html |url-status=dead }} scientists reported, based on Carbon Monitor{{cite web |title=Carbon monitor |url=https://carbonmonitor.org/ |website=carbonmonitor.org |access-date=19 April 2022}} (CM) data, that after COVID-19-pandemic-caused record-level declines in 2020, global {{CO2}} emissions rebounded sharply by 4.8% in 2021, indicating that at the current trajectory, the carbon budget for a {{frac|2|3}} likelihood for limiting warming to 1.5 °C would be used up within 9.5 years.{{cite journal |last1=Liu |first1=Zhu |last2=Deng |first2=Zhu |last3=Davis |first3=Steven J. |last4=Giron |first4=Clement |last5=Ciais |first5=Philippe |title=Monitoring global carbon emissions in 2021 |journal=Nature Reviews Earth & Environment |date=April 2022 |volume=3 |issue=4 |pages=217–219 |doi=10.1038/s43017-022-00285-w |pmid=35340723 |pmc=8935618 |bibcode=2022NRvEE...3..217L |language=en |issn=2662-138X}}

In April 2022, the now reviewed and officially published The Global Carbon Budget 2021 concluded that fossil {{CO2}} emissions rebounded{{cite journal |last1=Jackson |first1=R B |last2=Friedlingstein |first2=P |last3=Le Quéré |first3=C |last4=Abernethy |first4=S |last5=Andrew |first5=R M |last6=Canadell |first6=J G |last7=Ciais |first7=P |last8=Davis |first8=S J |last9=Deng |first9=Zhu |last10=Liu |first10=Zhu |last11=Korsbakken |first11=J I |last12=Peters |first12=G P |title=Global fossil carbon emissions rebound near pre-COVID-19 levels |journal=Environmental Research Letters |date=1 March 2022 |volume=17 |issue=3 |pages=031001 |doi=10.1088/1748-9326/ac55b6 |arxiv=2111.02222 |bibcode=2022ERL....17c1001J |s2cid=241035429 |language=en}} from pandemic levels by around +4.8% relative to 2020 emissions – returning to 2019 levels.

It identifies three major issues for improving reliable accuracy of monitoring, shows that China and India surpassed 2019 levels (by 5.7% and 3.2%) while the EU and the US stayed beneath 2019 levels (by 5.3% and 4.5%), quantifies various changes and trends, for the first time provides models' estimates that are linked to the official country GHG inventories reporting, and suggests that the remaining carbon budget at 1. Jan 2022 for a 50% likelihood to limit global warming to 1.5 °C (albeit a temporary exceedence is to be expected) is 120 GtC (420 Gt{{CO2}}) – or 11 years of 2021 emissions levels.

This does not mean that likely 11 years remain to cut emissions but that if emissions stayed the same, instead of increasing like in 2021, 11 years of constant GHG emissions would be left in the hypothetical scenario that all emissions suddenly ceased in the 12th year. (The 50% likelihood may be describable as a kind of minimum plausible deniability requirement as lower likelihoods would make the 1.5 °C goal "unlikely".) Moreover, other trackers show (or highlight) different amounts of carbon budget left, such as the MCC, which as of May 2022 shows "7 years 1 month left" and different likelihoods have different carbon budgets: a 83% likelihood would mean 6.6 ±0.1 years left (ending in 2028) according to CM data.

In October 2023 a group of researchers updated the carbon budget including the CO2 emitted at 2020-2022 and new findings about the role of reduced presence of polluting particles in the atmosphere.{{cite journal |last1=Lamboll |first1=Robin D. |last2=Nicholls |first2=Zebedee R. J. |last3=Smith |first3=Christopher J. |last4=Kikstra |first4=Jarmo S. |last5=Byers |first5=Edward |last6=Rogelj |first6=Joeri |title=Assessing the size and uncertainty of remaining carbon budgets |journal=Nature Climate Change |date=December 2023 |volume=13 |issue=12 |pages=1360–1367 |doi=10.1038/s41558-023-01848-5|doi-access=free |bibcode=2023NatCC..13.1360L }} They found we can emit 250 GtCO₂ or 6 years of emissions at current level starting from January 2023, for having a 50% chance to stay below 1.5 degrees. For reaching this target humanity will need to zero CO₂ emissions by the year 2034. To have a 50% chance of staying below 2 degrees humanity can emit 1220 Gt{{CO2}} or 30 years of emissions at current level.{{cite news |last1=McGrath |first1=Matt |title=Carbon emissions threaten 1.5C climate threshold sooner than thought - report |url=https://www.bbc.com/news/science-environment-67242386 |access-date=1 November 2023 |agency=BBC |publisher=Nature Climate Change |date=31 October 2023}}{{cite news |last1=BORENSTEIN |first1=SETH |title=Earth Will Lock in 1.5°C of Warming By 2029 At Current Rate of Burning Fossil Fuels |url=https://time.com/6329852/earth-will-hit-carbon-budget-warming-threshold-in-2029-study/ |access-date=1 November 2023 |agency=Times |date=30 October 2023}}

File:Figure-2-Scientific-evidence-vs-value-judgement-graphic-v2.jpg

The finding of an almost linear relationship between global temperature rise and cumulative carbon dioxide emissions{{cite journal |last1=Matthews |first1=H. Damon |last2=Gillett |first2=Nathan P. |last3=Stott |first3=Peter A. |last4=Zickfeld |first4=Kirsten |title=The proportionality of global warming to cumulative carbon emissions |journal=Nature |date=June 2009 |volume=459 |issue=7248 |pages=829–832 |doi=10.1038/nature08047 |pmid=19516338 |bibcode=2009Natur.459..829M |s2cid=4423773 }} has encouraged the estimation of global emissions budgets in order to remain below dangerous levels of warming. Since the pre-industrial period (year 1750) to 2019, approximately 2390 Gigatonnes of {{CO2}} (Gt {{CO2}}) has already been emitted globally.

Scientific estimations of the remaining global emissions budgets/quotas differ due to varied methodological approaches, and considerations of thresholds.{{cite journal|last1=Rogelj|first1=Joeri|last2=Schaeffer|first2=Michiel|last3=Friedlingstein|first3=Pierre|last4=Gillett|first4=Nathan P.|last5=van Vuuren|first5=Detlef P.|last6=Riahi|first6=Keywan|last7=Allen|first7=Myles|last8=Knutti|first8=Reto|date=24 February 2016|title=Differences between carbon budget estimates unravelled|journal=Nature Climate Change|volume=6|issue=3|pages=245–252|bibcode=2016NatCC...6..245R|doi=10.1038/nclimate2868|hdl=1874/330323|s2cid=87929010 |hdl-access=free}} Estimations might not include all amplifying climate change feedbacks,{{cite journal |last1=Rogelj |first1=Joeri |last2=Forster |first2=Piers M. |last3=Kriegler |first3=Elmar |last4=Smith |first4=Christopher J. |last5=Séférian |first5=Roland |title=Estimating and tracking the remaining carbon budget for stringent climate targets |journal=Nature |date=17 July 2019 |volume=571 |issue=7765 |pages=335–342 |doi=10.1038/s41586-019-1368-z |pmid=31316194 |bibcode=2019Natur.571..335R |doi-access=free |hdl=10044/1/78011 |hdl-access=free }}{{Cite web|url=https://blogs.scientificamerican.com/observations/scientists-have-been-underestimating-the-pace-of-climate-change/|title=Scientists Have Been Underestimating the Pace of Climate Change|last=Jamieson|first=Naomi Oreskes, Michael Oppenheimer, Dale|website=Scientific American Blog Network|language=en|access-date=2019-08-21}}{{Cite journal|last=Comyn-Platt|first=Edward|date=2018|title=Carbon budgets for 1.5 and 2 °C targets lowered by natural wetland and permafrost feedbacks|journal=Nature Geoscience|volume=11|issue=8|pages=568–573|doi=10.1038/s41561-018-0174-9|bibcode=2018NatGe..11..568C|s2cid=134078252|url=http://centaur.reading.ac.uk/77371/3/NaturalCH4_Permafrost_EmissionBudgets_FinalEdit.pdf}}{{Cite journal|last1=Lenton|first1=Timothy M.|last2=Rockström|first2=Johan|last3=Gaffney|first3=Owen|last4=Rahmstorf|first4=Stefan|last5=Richardson|first5=Katherine|last6=Steffen|first6=Will|last7=Schellnhuber|first7=Hans Joachim|date=2019-11-27|title=Climate tipping points — too risky to bet against|journal=Nature|language=en|volume=575|issue=7784|pages=592–595|doi=10.1038/d41586-019-03595-0|pmid=31776487|bibcode=2019Natur.575..592L|doi-access=free|hdl=10871/40141|hdl-access=free}} although the most authoritative carbon budget assessments as summarised by the IPCC do account explicitly for these.{{cite book |url=http://www.ipcc.ch/report/sr15/ |title=Mitigation pathways compatible with 1.5°C in the context of sustainable development |vauthors=Rogelj J, Shindell D, Jiang K, Fifita S, Forster P, Ginzburg V, Handa C, Kheshgi H, Kobayashi S, Kriegler E, Mundaca L, Séférian R, Vilariño MV |date=2018 |publisher=IPCC/WMO |veditors=Flato G, Fuglestvedt J, Mrabet R, Schaeffer R |pages=93–174 |chapter=Global Warming of 1.5 °C: an IPCC special report on the impacts of global warming of 1.5 °C above pre-industrial levels and related global greenhouse gas emission pathways, in the context of strengthening the global response to the threat of climate change, sustainable development, and efforts to eradicate poverty}} Scientists assess the size of remaining carbon budgets using estimates of:

• past warming caused by human activities,
• the amount of warming per cumulative unit of CO₂ emissions (also known as the Transient Climate Response to cumulative Emissions of carbon dioxide, or TCRE),
• the amount of warming that could still occur once all emissions of CO₂ are halted (known as the Zero Emissions Commitment{{Cite journal|last1=MacDougall|first1=Andrew H.|last2=Frölicher|first2=Thomas L.|last3=Jones|first3=Chris D.|last4=Rogelj|first4=Joeri|last5=Matthews|first5=H. Damon|last6=Zickfeld|first6=Kirsten|last7=Arora|first7=Vivek K.|last8=Barrett|first8=Noah J.|last9=Brovkin|first9=Victor|last10=Burger|first10=Friedrich A.|last11=Eby|first11=Micheal|date=2020-06-15|title=Is there warming in the pipeline? A multi-model analysis of the Zero Emissions Commitment from {{CO2}}|url=https://bg.copernicus.org/articles/17/2987/2020/|journal=Biogeosciences|language=en|volume=17|issue=11|pages=2987–3016|doi=10.5194/bg-17-2987-2020|bibcode=2020BGeo...17.2987M |issn=1726-4189 |doi-access=free |hdl=10044/1/79876|hdl-access=free}}), and
• the impact of Earth system feedbacks that would otherwise not be covered.

The estimates vary according to the global temperature target that is chosen, the probability of staying below that target, and the emission of other non-{{CO2}} greenhouse gases (GHGs).{{cite journal|last1=Friedlingstein|first1=P.|last2=Andrew|first2=R. M.|last3=Rogelj|first3=J.|last4=Peters|first4=G. P.|last5=Canadell|first5=J. G.|last6=Knutti|first6=R.|last7=Luderer|first7=G.|last8=Raupach|first8=M. R.|last9=Schaeffer|first9=M.|last10=van Vuuren|first10=D. P.|last11=Le Quéré|first11=C.|date=October 2014|title=Persistent growth of CO 2 emissions and implications for reaching climate targets|journal=Nature Geoscience|volume=7|issue=10|pages=709–715|bibcode=2014NatGe...7..709F|citeseerx=10.1.1.711.8978|doi=10.1038/ngeo2248|s2cid=129068170 }} This approach was first applied in the 2018 Special report on Global Warming of 1.5 °C by the IPCC, and was also used in its 2021 Working Group I Contribution to the Sixth Assessment Report.

Carbon budget estimates depend on the likelihood or probability of avoiding a temperature limit, and the assumed warming that is projected to be caused by non-{{CO2}} emissions. These estimates assume non-{{CO2}} emissions are also reduced in line with deep decarbonisation scenarios that reach global net zero {{CO2}} emissions. Carbon budget estimates thus depend on how successful society is in reducing non-{{CO2}} emissions together with carbon dioxide emissions. Scientists estimated that remaining carbon budgets can be 220 Gt {{CO2}} higher or lower depending on how successful non-{{CO2}} emissions are reduced.

{{clear}}

{{excerpt|Climate change mitigation||paragraphs=1|only=paragraphs}}

{{See also|Nationally determined contribution|List of countries by carbon dioxide emissions}}

Carbon budgets are applicable to the global level. To translate these global carbon budgets to the country level, a set of value judgments have to be made on how to distribute the total and remaining carbon budget. In light of the many differences between nations, including but not limited to population, level of industrialisation, national emissions histories, and mitigation capabilities, scientists have made attempts to allocate global carbon budgets among countries using methods that follow various principles of equity.{{cite journal | last1 = Ringius | first1 = L. | last2 = Torvanger | first2 = A. | last3 = Underdal | first3 = A. | year = 2002 | title = Burden sharing and fairness principles in international climate policy | url = https://folk.uio.no/stvau1/Journal%20articles/Burdensharing.pdf | journal = International Environmental Agreements | volume = 2 | issue = 1| pages = 1–22 | doi = 10.1023/a:1015041613785 | bibcode = 2002IEAPL...2....1R | s2cid = 73604803 }} Allocating national emissions budgets is comparable to sharing the effort to reduce global emissions, underlined by some assumptions of state-level responsibility of climate change. Many authors have conducted quantitative analyses which allocate emissions budgets,{{Cite journal |last1=Nabel |first1=Julia E.M.S. |last2=Rogelj |first2=Joeri |last3=Chen |first3=Claudine M. |last4=Markmann |first4=Kathleen |last5=Gutzmann |first5=David J.H. |last6=Meinshausen |first6=Malte |date=2011 |title=Decision support for international climate policy – The PRIMAP emission module |url=https://linkinghub.elsevier.com/retrieve/pii/S1364815211001873 |journal=Environmental Modelling & Software |language=en |volume=26 |issue=12 |pages=1419–1433 |doi=10.1016/j.envsoft.2011.08.004|bibcode=2011EnvMS..26.1419N |url-access=subscription }}{{Cite journal |last1=Anderson |first1=Kevin |last2=Broderick |first2=John F. |last3=Stoddard |first3=Isak |date=2020-05-28 |title=A factor of two: how the mitigation plans of 'climate progressive' nations fall far short of Paris-compliant pathways |journal=Climate Policy |volume=20 |issue=10 |pages=1290–1304 |doi=10.1080/14693062.2020.1728209 |issn=1469-3062 |doi-access=free|bibcode=2020CliPo..20.1290A }} often simultaneously addressing disparities in historical GHG emissions between nations.

One guiding principle that is used to allocate global emissions budgets to nations is the principle of "common but differentiated responsibilities and respective capabilities" that is included in the United Nations Framework Convention on Climate Change (UNFCCC). This principle is not defined in further detail in the UNFCCC but is broadly understood to recognize nations' different cumulative historical contributions to global emissions as well as their different development stages. From this perspective, those countries with greater emissions during a set time period (for example, since the pre-industrial era to the present) are the most responsible for addressing excess emissions, as are countries that are richer. Thus, their national emissions budgets have to be smaller than those from countries that have polluted less in the past, or are poorer. The concept of national historical responsibility for climate change has prevailed in the literature since the early 1990s{{cite journal | last1 = Grübler | first1 = A. | last2 = Fujii | first2 = Y. | year = 1991 | title = Inter-generational and spatial equity issues of carbon accounts | journal = Energy | volume = 16 | issue = 11–12| pages = 1397–1416 | doi = 10.1016/0360-5442(91)90009-b | bibcode = 1991Ene....16.1397G | url = http://pure.iiasa.ac.at/id/eprint/3489/1/RR-92-06.pdf }}{{cite journal | last1 = Smith | first1 = K. R. | year = 1992 | title = Allocating responsibility for global warming: The natural debt index | journal = Ambio. Stockholm | volume = 20 | issue = 2| pages = 95–96 }} and has been part of the key international agreements on climate change (UNFCCC, the Kyoto Protocol and the Paris Agreement). Consequently, those countries with the highest cumulative historical emissions have the most responsibility to take the strongest actions{{cite journal |last1=Botzen |first1=W. J. W. |last2=Gowdy |first2=J. M. |last3=Bergh |first3=J. C. J. M. Van Den |title=Cumulative CO₂ emissions: shifting international responsibilities for climate debt |journal=Climate Policy |date=1 January 2008 |volume=8 |issue=6 |pages=569–576 |doi=10.3763/cpol.2008.0539 |bibcode=2008CliPo...8..569B |s2cid=153972794 }} and help developing countries to mitigate their emissions and adapt to climate change. This principle is recognized in international treaties and has been part of the diplomatic strategies by developing countries, that argue that they need larger emissions budgets{{cite journal | last1 = Pan | first1 = J | year = 2003 | title = Emissions rights and their transferability: equity concerns over climate change mitigation | journal = International Environmental Agreements | volume = 3 | issue = 1| pages = 1–16 | doi = 10.1023/A:1021366620577 | bibcode = 2003IEAPL...3....1P | s2cid = 18008551 }} to reduce inequity and achieve sustainable development.

Another common equity principle for calculating national emissions budgets is the "egalitarian" principle. This principle stipulates individuals should have equal rights, and therefore emissions budgets should be distributed proportionally according to state populations. Some scientists have thus reasoned the use of national per-capita emissions in national emissions budget calculations.{{cite journal | last1 = Baer | first1 = P. | last2 = Athanasiou | first2 = T. | last3 = Kartha | first3 = S. | last4 = Kemp-Benedict | first4 = E. | year = 2009 | title = Greenhouse development rights: A proposal for a fair global climate treaty | journal = Ethics Place and Environment | volume = 12 | issue = 3| pages = 267–281 | doi = 10.1080/13668790903195495 | bibcode = 2009EPlaE..12..267B | s2cid = 153611101 }}{{cite journal |last1=Matthews |first1=H. Damon |s2cid=87930705 |title=Quantifying historical carbon and climate debts among nations |journal=Nature Climate Change |date=7 September 2015 |volume=6 |issue=1 |pages=60–64 |doi=10.1038/nclimate2774 |bibcode=2016NatCC...6...60M }}{{Cite journal|last=Neumayer|first=Eric|title=In defence of historical accountability for greenhouse gas emissions|journal=Ecological Economics|volume=33|issue=2|pages=185–192|doi=10.1016/s0921-8009(00)00135-x|year=2000|bibcode=2000EcoEc..33..185N |s2cid=154625649|url=http://eprints.lse.ac.uk/18906/1/__Libfile_repository_Content_Neumayer%2C%20E_In%20defense%20of%20historical%20accountability%20for%20greenhouse%20gas%20emissions_In%20defense%20of%20historical%20accountability%20for%20greenhouse%20gas%20emissions%20%28LSE%20RO%29.pdf}} This principle may be favoured by nations with larger or rapidly growing populations, but raises the question whether individuals can have a right to pollute.{{Cite journal |last=Caney |first=Simon |date=2009 |title=Justice and the distribution of greenhouse gas emissions1 |url=http://www.tandfonline.com/doi/abs/10.1080/17449620903110300 |journal=Journal of Global Ethics |language=en |volume=5 |issue=2 |pages=125–146 |doi=10.1080/17449620903110300 |s2cid=144368369 |issn=1744-9626|url-access=subscription }}

A third equity principle that has been employed in national budget calculations considers national sovereignty. The "sovereignty" principle highlights the equal right of nations to pollute. The grandfathering method for calculating national emissions budgets uses this principle. Grandfathering allocates these budgets proportionally according to emissions at a particular base year, and has been used under international regimes such as the Kyoto ProtocolUNFCCC (1998). "Kyoto Protocol to the United Nations Framework Convention on Climate Change".(http://unfccc.int/resource/docs/convkp/kpeng.pdf ) and the early phase of the European Union Emissions Trading Scheme (EU ETS){{CELEX|32010D0384|text=2010/384/: Commission Decision of 9 July 2010 on the Community-wide quantity of allowances to be issued under the EU Emission Trading Scheme for 2013 (notified under document C(2010) 4658)}} This principle is often favoured by developed countries, as it allocates larger emissions budgets to them. However, recent publications highlight that grandfathering is unsupported as an equity principle as it "creates 'cascading biases' against poorer states,{{Cite journal |last1=Kartha |first1=Sivan |last2=Athanasiou |first2=Tom |last3=Caney |first3=Simon |last4=Cripps |first4=Elizabeth |last5=Dooley |first5=Kate |last6=Dubash |first6=Navroz K. |last7=Fei |first7=Teng |last8=Harris |first8=Paul G. |last9=Holz |first9=Christian |last10=Lahn |first10=Bård |last11=Moellendorf |first11=Darrel |date=2018 |title=Cascading biases against poorer countries |url=http://www.nature.com/articles/s41558-018-0152-7 |journal=Nature Climate Change |language=en |volume=8 |issue=5 |pages=348–349 |doi=10.1038/s41558-018-0152-7 |bibcode=2018NatCC...8..348K |hdl=20.500.11820/015eb0b4-9942-41f5-afa9-0f0c2a94deff |s2cid=90164339 |issn=1758-678X|hdl-access=free }} is not a 'standard of equity'{{Cite journal |last1=Dooley |first1=Kate |last2=Holz |first2=Christian |last3=Kartha |first3=Sivan |last4=Klinsky |first4=Sonja |last5=Roberts |first5=J. Timmons |last6=Shue |first6=Henry |last7=Winkler |first7=Harald |last8=Athanasiou |first8=Tom |last9=Caney |first9=Simon |last10=Cripps |first10=Elizabeth |last11=Dubash |first11=Navroz K. |date=2021 |title=Ethical choices behind quantifications of fair contributions under the Paris Agreement |url=http://www.nature.com/articles/s41558-021-01015-8 |journal=Nature Climate Change |language=en |volume=11 |issue=4 |pages=300–305 |doi=10.1038/s41558-021-01015-8 |bibcode=2021NatCC..11..300D |s2cid=232766664 |issn=1758-678X|hdl=11250/2828413 |hdl-access=free }}".{{Cite journal |last1=Rajamani |first1=Lavanya |last2=Jeffery |first2=Louise |last3=Höhne |first3=Niklas |last4=Hans |first4=Frederic |last5=Glass |first5=Alyssa |last6=Ganti |first6=Gaurav |last7=Geiges |first7=Andreas |date=2021-09-14 |title=National 'fair shares' in reducing greenhouse gas emissions within the principled framework of international environmental law |journal=Climate Policy |language=en |volume=21 |issue=8 |pages=983–1004 |doi=10.1080/14693062.2021.1970504 |s2cid=238231789 |issn=1469-3062|doi-access=free |bibcode=2021CliPo..21..983R }} Other scholars have highlighted that "to treat states as the owners of emission rights has morally problematic consequences".

• Carbon price
• Economic analysis of climate change
• Global Carbon Project

{{Reflist}}

• [https://www.globalcarbonproject.org/ Global Carbon Project]
• [https://constrain-eu.org/ The CONSTRAIN Project] - 4-year project (2020 to 2024) funded by European Union Horizon 2020

{{Climate change}}

Category:Greenhouse gas emissions

Category:Environmental science

Category:Climate change mitigation