Editing Emissions trading (section)

==Trading systems==
Apart from the dynamic development in [[carbon emission trading]], other pollutants have also been targeted.

===United States===
====Sulfur dioxide====
{{main|Acid Rain Program}}
An early example of an emission trading system has been the [[sulfur dioxide]] (SO<sub>2</sub>) trading system under the framework of the [[Acid Rain Program]] of the 1990 [[Clean Air Act (1990)|Clean Air Act]] in the U.S. Under the program, which is essentially a cap-and-trade emissions trading system, SO<sub>2</sub> emissions were reduced by 50% from 1980 levels by 2007.<ref>{{cite web
|url=http://www.epa.gov/airmarkt/progress/arp07.html
|title=Acid Rain Program 2007 Progress Report
|work=Clean Air Markets - Air & Radiation
|publisher=US EPA
|date=January 2009
|access-date=2011-07-25
|archive-date=2011-05-01
|archive-url=https://web.archive.org/web/20110501114253/http://www.epa.gov/airmarkt/progress/arp07.html
|url-status=live
}}</ref> Some experts argue that the cap-and-trade system of SO<sub>2</sub> emissions reduction has reduced the cost of controlling acid rain by as much as 80% versus source-by-source reduction.<ref name="stavins98"/><ref>{{cite journal | last1 = Carlson | first1 = Curtis | last2 = Burtraw | first2 = Dallas | last3 = Cropper | first3 = Maureen | last4 = Palmer | first4 = Karen L. | year = 2000 | title = Sulfur dioxide control by electric utilities: What are the gains from trade? | url = http://ageconsearch.umn.edu/record/10790/files/dp980044.pdf| journal = Journal of Political Economy | volume = 108 | issue = 6| pages = 1292–1326 | doi=10.1086/317681| s2cid = 3037737 }}</ref> The SO<sub>2</sub> program was challenged in 2004, which set in motion a series of events that led to the 2011 [[Cross-State Air Pollution Rule]] (CSAPR).  Under the CSAPR, the national SO<sub>2</sub> trading program was replaced by four separate trading groups for SO<sub>2</sub> and NO<sub>x</sub>.<ref>{{cite web
 |url         = http://www.epa.gov/crossstaterule/
 |title       = Cross-State Air Pollution Rule (CSAPR)
 |date        = 2011-07-09
 |access-date  = 2011-07-10
 |publisher   = United States Environment Protection Agency
 |url-status     = dead
 |archive-url  = https://web.archive.org/web/20110711010737/http://www.epa.gov/crossstaterule/
 |archive-date = 2011-07-11
}}</ref>
SO<sub>2</sub> emissions from Acid Rain Program sources have fallen from 17.3 million tons in 1980 to about 7.6 million tons in 2008, a decrease in emissions of 56 percent.  A 2014 EPA analysis estimated that implementation of the Acid Rain Program avoided between 20,000 and 50,000 incidences of premature mortality annually due to reductions of ambient PM2.5 concentrations, and between 430 and 2,000 incidences annually due to reductions of ground-level ozone.<ref name="ex" />{{failed verification|date=June 2017}}

====Nitrogen oxides====
In 2003, the Environmental Protection Agency (EPA) began to administer the {{NOx}} Budget Trading Program (NBP) under the {{NOx}} State Implementation Plan (also known as the "NOx SIP Call"). The {{NOx}} Budget Trading Program was a market-based cap and trade program created to reduce emissions of nitrogen oxides (NO<sub>x</sub>) from power plants and other large combustion sources in the eastern United States. NO<sub>x</sub> is a prime ingredient in the formation of ground-level ozone ([[smog]]), a pervasive air pollution problem in many areas of the eastern United States. The NBP was designed to reduce NO<sub>x</sub> emissions during the warm summer months, referred to as the ozone season, when ground-level ozone concentrations are highest.<ref>[https://www.epa.gov/airmarkets/nox-budget-trading-program "NOx Budget Trading Program"] {{Webarchive|url=https://web.archive.org/web/20170426055618/https://www.epa.gov/airmarkets/nox-budget-trading-program |date=2017-04-26 }}, Environmental Protection Agency. Retrieved 25 April 2017.</ref> In March 2008, EPA again strengthened the 8-hour ozone standard to 0.075 parts per million (ppm) from its previous 0.08 ppm.<ref>[https://www.epa.gov/sites/production/files/2015-08/documents/ozone_fact_sheet.pdf "Ozone Fact Sheet"] {{Webarchive|url=https://web.archive.org/web/20170222022508/https://www.epa.gov/sites/production/files/2015-08/documents/ozone_fact_sheet.pdf |date=2017-02-22 }}, Environmental Protection Agency. Retrieved 25 April 2017.</ref>

Ozone season {{NOx}} emissions decreased by 43 percent between 2003 and 2008, even while energy demand remained essentially flat during the same period. CAIR will result in $85 billion to $100 billion in health benefits and nearly $2 billion in visibility benefits per year by 2015 and will substantially reduce premature mortality in the eastern United States.<ref>{{Cite web |title=BGC Environmental Brokerage Service {{!}} Environment {{!}} Clean Air Interstate Rule |url=http://www.bgcebs.com/Emissions/?page=USAComp_CAIR |access-date=2024-09-12 |website=www.bgcebs.com}}</ref>
NOx reductions due to the {{NOx}} Budget Trading Program have led to improvements in ozone and PM2.5, saving an estimated 580 to 1,800 lives in 2008.<ref name="ex">{{cite web
|title=Cap and Trade
|url=http://www.epa.gov/captrade/
|publisher=United States Environmental Protection Agency
|access-date=27 October 2014
|archive-date=8 November 2014
|archive-url=https://web.archive.org/web/20141108041221/http://www.epa.gov/captrade/
|url-status=live
}}</ref>{{failed verification|date=June 2017}}

A 2017 study in the ''[[The American Economic Review|American Economic Review]]'' found that the {{NOx}} Budget Trading Program decreased {{NOx}} emissions and ambient ozone concentrations.<ref name=":2">{{Cite journal|first1=Olivier|last1=Deschênes|first2=Michael|last2=Greenstone|last3=Shapiro|first3= Joseph|date=2017|title=Defensive Investments and the Demand for Air Quality: Evidence from the NOx Budget Program|journal=American Economic Review|volume=107|issue=10|pages=2958–2989|doi=10.1257/aer.20131002|issn=0002-8282|doi-access=free}}</ref> The program reduced expenditures on medicine by about 1.5% ($800 million annually) and reduced the mortality rate by up to 0.5% (2,200 fewer premature deaths, mainly among individuals 75 and older).<ref name=":2" />

====Volatile organic compounds====
[[File:Classification List of Organic Pollutants.png|thumb|276x276px|Classification of Organic Pollutants]]
In the United States the [[United States Environmental Protection Agency|Environmental Protection Agency]] (EPA) classifies [[Volatile organic compound|Volatile Organic Compounds]] (VOCs) as gases emitted from certain solids and liquids that may have adverse health effects.<ref name="EPA, OAR, ORIA, IED">{{Cite web|url=https://www.epa.gov/indoor-air-quality-iaq/volatile-organic-compounds-impact-indoor-air-quality|title=Volatile Organic Compounds' Impact on Indoor Air Quality {{!}} US EPA|last=EPA, OAR, ORIA, IED|first=US|website=US EPA|date=18 August 2014|access-date=2017-11-30|archive-date=2017-11-22|archive-url=https://web.archive.org/web/20171122160317/https://www.epa.gov/indoor-air-quality-iaq/volatile-organic-compounds-impact-indoor-air-quality|url-status=live}}</ref> These VOCs include a variety of chemicals that are emitted from a variety of different products.<ref name="EPA, OAR, ORIA, IED"/> These include products such as gasoline, perfumes, hair spray, fabric cleaners, PVC, and refrigerants; all of which can contain chemicals such as benzene, acetone, methylene chloride, freons, formaldehyde.<ref>{{Cite web|url=https://www.health.ny.gov/environmental/indoors/voc.htm|title=Volatile Organic Compounds (VOCs) in Commonly Used Products|website=www.health.ny.gov|access-date=2017-11-30|archive-url=https://web.archive.org/web/20180111012716/https://www.health.ny.gov/environmental/indoors/voc.htm|archive-date=2018-01-11|url-status=dead}}</ref>

VOCs are also monitored by the [[United States Geological Survey]] for its presence in groundwater supply.<ref name="Synthesis">{{Cite web|url=https://water.usgs.gov/nawqa/vocs/national_assessment/report/chapter1.html|title=Chapter 1 - Major Findings and Conclusions|last=Synthesis|first=NAWQA VOC National|website=water.usgs.gov|access-date=2017-11-30|archive-date=2017-05-18|archive-url=https://web.archive.org/web/20170518023924/https://water.usgs.gov/nawqa/vocs/national_assessment/report/chapter1.html|url-status=live}}</ref> The USGS concluded that many of the nations aquifers are at risk to low-level VOC contamination.<ref name="Synthesis"/> The common symptoms of short levels of exposure to VOCs include headaches, nausea, and eye irritation.<ref name="health.state.mn.us">{{Cite web|url=http://www.health.state.mn.us/divs/eh/indoorair/voc/|title=Volatile Organic Compounds (VOCs) in Your Home - EH: Minnesota Department of Health|website=www.health.state.mn.us|access-date=2017-11-30|archive-url=https://web.archive.org/web/20171201030617/http://www.health.state.mn.us/divs/eh/indoorair/voc/|archive-date=2017-12-01|url-status=dead}}</ref> If exposed for an extended period of time the symptoms include cancer and damage to the central nervous system.<ref name="health.state.mn.us"/>

===China===
In an effort to reverse the adverse consequences of air pollution, in 2006, China started to consider a national pollution permit trading system in order to use market-based mechanisms to incentivize companies to cut pollution.<ref>{{Cite web|url=https://www.washingtonpost.com/wp-dyn/content/article/2006/03/28/AR2006032801565.html|title=China Considers Tradable Pollution-Rights Permits|last=Bartson|first=Andrew|date=March 29, 2006|website=The Wall Street Journal|access-date=January 27, 2019|archive-date=December 14, 2017|archive-url=https://web.archive.org/web/20171214064049/http://www.washingtonpost.com/wp-dyn/content/article/2006/03/28/AR2006032801565.html|url-status=live}}</ref> This has been based on a previous pilot project called the Industrial {{SO2}} emission trading pilot scheme, which was launched in 2002. Four provinces, three municipalities and one [[State-owned enterprises of China|state-owned enterprise]] were involved in this pilot project (also known as the 4+3+1 project).<ref name=":92">{{Cite book |last=Ding |first=Iza |title=Greening East Asia: The Rise of the Eco-Developmental State |date=2020 |publisher=[[University of Washington Press]] |isbn=978-0-295-74791-0 |editor-last=Esarey |editor-first=Ashley |location=Seattle |chapter=Pollution Emissions Trading in China |jstor=j.ctv19rs1b2 |editor-last2=Haddad |editor-first2=Mary Alice |editor-last3=Lewis |editor-first3=Joanna I. |editor-last4=Harrell |editor-first4=Stevan}}</ref>{{Rp|page=80}} They are Shandong, Shanxi, Jiangsu, Henan, Shanghai, Tianjin, Liuzhou and [[China Huaneng Group]], a state-owned company in the power industry.<ref name=":4">{{Cite journal|s2cid=17764664|date=2014|title=Can China's Industrial SO<sub>2</sub> Emissions Trading Pilot Scheme Reduce Pollution Abatement Costs?|journal=Sustainability|volume=6|pages=7621–7645|doi=10.3390/su6117621|last1=Tu|first1=Zhengge|last2=Shen|first2=Renjun|issue=11|doi-access=free|bibcode=2014Sust....6.7621T }}</ref>

In 2014, when the Chinese government started considering a national level pollution permit trading system again, there were more than 20 local pollution permit trading platforms. The Yangtze River Delta region as a whole has also run test trading, but the scale was limited.<ref name=":5">{{Cite news|url=https://www.under2coalition.org/what-we-do/news-and-blogs/china-considers-national-pollution-permit-trading|title=China considers national pollution permit trading|date=2014-01-14|work=Under2 Coalition|access-date=2018-09-08|archive-date=2018-09-08|archive-url=https://web.archive.org/web/20180908130457/https://www.under2coalition.org/what-we-do/news-and-blogs/china-considers-national-pollution-permit-trading|url-status=live}}</ref> In the same year, the Chinese government proposed establishing a carbon market, focused on CO<sub>2</sub> reduction later in the decade, and it is a separate system from the pollution permit trading.<ref name=":5" />

Following these regional efforts, China established [[Chinese national carbon trading scheme|its national Emissions Trading System]] in 2017.<ref name=":32">{{Cite book |last=Lewis |first=Joanna I. |title=Cooperating for the Climate: Learning from International Partnerships in China's Clean Energy Sector |date=2023 |publisher=The [[MIT Press]] |isbn=978-0-262-54482-5 |location=Cambridge, Massachusetts}}</ref>{{Rp|page=28}}

A 2021 study in ''PNAS'' found that China's emissions trading system effectively reduced firm emissions despite low carbon prices and infrequent trading. The system reduced total emissions by 16.7% and [[emission intensity]] by 9.7%.<ref>{{Cite journal|last1=Cui|first1=Jingbo|last2=Wang|first2=Chunhua|last3=Zhang|first3=Junjie|last4=Zheng|first4=Yang|date=2021-12-28|title=The effectiveness of China's regional carbon market pilots in reducing firm emissions|journal=Proceedings of the National Academy of Sciences|language=en|volume=118|issue=52|doi=10.1073/pnas.2109912118|pmid=34930839|pmc=8719898|bibcode=2021PNAS..11809912C |issn=0027-8424|doi-access=free }}</ref>

===Linked trading systems===
Distinct cap-and-trade systems can be linked together through the mutual or unilateral recognition of emissions allowances for compliance. Linking systems creates a larger carbon market, which can reduce overall compliance costs, increase market liquidity and generate a more stable carbon market.<ref>[https://icapcarbonaction.com/index.php?option=com_attach&task=download&id=241 "Linking Emissions Trading Systems: A Summary of Current Research"] {{Webarchive|url=https://web.archive.org/web/20211120185930/https://icapcarbonaction.com/en/?option=com_attach&task=download&id=241 |date=2021-11-20 }}, ICAP 2015.</ref><ref>Burtraw, D., Palmer, K. L., Munnings, C., Weber, P., & Woerman, M., 2013: Linking by Degrees: Incremental Alignment of Cap-and-Trade Markets. SSRN Electronic Journal. {{doi|10.2139/ssrn.2249955}}</ref> Linking systems can also be politically symbolic as it shows willingness to undertake a common effort to reduce GHG emissions.<ref>Flachsland, C., Marschinski, R., & Edenhofer, O., 2009: To link or not to link: benefits and disadvantages of linking cap-and-trade systems. Climate Policy, 9(4), 358–372. {{doi|10.3763/cpol.2009.0626}}</ref> Some scholars have argued that linking may provide a starting point for developing a new, bottom-up international climate policy architecture, whereby multiple unique systems successively link their various systems.<ref>Ranson, M., & Stavins, R., 2013: Linkage of Greenhouse Gas Emissions Trading Systems - Learning from Experience. Discussion Paper Resources For The Future, No. 42</ref><ref>The House of Commons Energy and Climate Committee, 2015: Linking emissions trading systems. London.</ref>

In 2014, the U.S. state of California (which is the world's fifth largest economy if it were a nation, between Germany and the United Kingdom in size) and the Canadian province of Québec successfully linked their systems. In 2015, the provinces of Ontario and Manitoba agreed to join the linked system between Quebec and California.<ref>[http://www.cbc.ca/news/canada/montreal/quebec-ontario-manitoba-cap-and-trade-1.3354002 "Quebec, Ontario, Manitoba sign agreement to link cap-and-trade systems"] {{Webarchive|url=https://web.archive.org/web/20160629143555/http://www.cbc.ca/news/canada/montreal/quebec-ontario-manitoba-cap-and-trade-1.3354002 |date=2016-06-29 }}, CBC News, 7 December 2015.</ref> On 22 September 2017, the [[Premier (Canada)|premiers]] of Quebec and Ontario, and the [[Governor of California]], signed the formal agreement establishing the linkage.<ref>{{cite web|title=California-Ontario-Québec Agreement on the Harmonization and Integration of their Cap-and-Trade Programs|url=https://www.arb.ca.gov/cc/capandtrade/linkage/2017_linkage_agreement_ca-qc-on.pdf|website=California Air Resources Board|publisher=[[Government of California]]|access-date=14 November 2017|archive-date=14 November 2017|archive-url=https://web.archive.org/web/20171114145218/https://www.arb.ca.gov/cc/capandtrade/linkage/2017_linkage_agreement_ca-qc-on.pdf|url-status=live}}</ref>

===Renewable energy certificates===
{{Main|Renewable Energy Certificates}}
[[Renewable Energy Certificates]] (occasionally referred to as or "green tags"), are a largely unrelated form of market-based instruments that are used to achieve renewable energy targets, which may be environmentally motivated (like emissions reduction targets), but may also be motivated by other aims, such as energy security or industrial policy.