Editing Carbon dioxide (section)

== Commercial uses ==
[[File:CO2 use in 2015 - IEA.png|thumb|alt=Pie chart of commercial CO2 use. See caption for description.|The biggest commercial uses of CO2 are in producing urea for fertilizer and in extracting oil from the ground. Beverages, food, metal fabrication, and other uses account for 3%, 3%, 2%, and 4% of commercial CO2 use, respectively.<ref>{{Cite web |date=2019-09-25 |title=Putting CO2 to Use – Analysis |url=https://www.iea.org/reports/putting-co2-to-use |access-date=2024-11-01 |website=IEA |at=Figure 1 |language=en-GB}}</ref>]]
Around 230 Mt of {{CO2}} are used each year,<ref>{{Cite web |title=CO2 Capture and Utilisation - Energy System |url=https://www.iea.org/energy-system/carbon-capture-utilisation-and-storage/co2-capture-and-utilisation |access-date=2024-10-30 |website=IEA |language=en-GB}}</ref> mostly in the fertiliser industry for urea production (130 million tonnes) and in the oil and gas industry for [[enhanced oil recovery]] (70 to 80 million tonnes).<ref name="IEA-2019-3"/>{{Rp|page=3}} Other commercial applications include food and beverage production, metal fabrication, cooling, fire suppression and stimulating plant growth in greenhouses.<ref name="IEA-2019-3" />{{Rp|page=3}}

Technology exists to [[Carbon capture and storage|capture {{CO2}} from industrial flue gas]] or [[Direct air capture|from the air]]. Research is ongoing on ways to use [[Carbon capture and storage#CO2 utilization in products|captured {{CO2}} in products]] and some of these processes have been deployed commercially.<ref name="Dziejarski-2023">{{Cite journal |last1=Dziejarski |first1=Bartosz |last2=Krzyżyńska |first2=Renata |last3=Andersson |first3=Klas |date=June 2023 |title=Current status of carbon capture, utilization, and storage technologies in the global economy: A survey of technical assessment |journal=Fuel |volume=342 |pages=127776 |bibcode=2023Fuel..34227776D |doi=10.1016/j.fuel.2023.127776 |issn=0016-2361 |doi-access=free}}[[File:CC-BY_icon.svg|50x50px]] Text was copied from this source, which is available under a [[creativecommons:by/4.0/|Creative Commons Attribution 4.0 International License]]</ref> However, the potential to use products is very small compared to the total volume of {{CO2}} that could foreseeably be captured.<ref name="IEA-2024">{{Cite web |title=CO2 Capture and Utilisation - Energy System |url=https://www.iea.org/energy-system/carbon-capture-utilisation-and-storage/co2-capture-and-utilisation |access-date=2024-07-18 |website=IEA |language=en-GB}}[[File:CC-BY_icon.svg|50x50px]] Text was copied from this source, which is available under a [[creativecommons:by/4.0/|Creative Commons Attribution 4.0 International License]]</ref> The vast majority of captured {{CO2}} is considered a waste product and sequestered in underground geologic formations.<ref name="Sekera-2020">{{Cite journal |last1=Sekera |first1=June |last2=Lichtenberger |first2=Andreas |date=6 October 2020 |title=Assessing Carbon Capture: Public Policy, Science, and Societal Need: A Review of the Literature on Industrial Carbon Removal |journal=Biophysical Economics and Sustainability |volume=5 |issue=3 |pages=14 |bibcode=2020BpES....5...14S |doi=10.1007/s41247-020-00080-5 |issn= |doi-access=free}}Text was copied from this source, which is available under a [[creativecommons:by/4.0/|Creative Commons Attribution 4.0 International License]]</ref>

=== Precursor to chemicals ===
{{expand section|date=July 2014}}
{{See also|Sabatier reaction}}
In the chemical industry, carbon dioxide is mainly consumed as an ingredient in the production of [[urea]], with a smaller fraction being used to produce [[methanol]] and a range of other products.<ref>{{cite web|url=https://www.ipcc.ch/pdf/special-reports/srccs/srccs_chapter7.pdf|title=IPCC Special Report on Carbon dioxide Capture and Storage|publisher=The Intergovernmental Panel on Climate Change|access-date=4 September 2015|archive-url=https://web.archive.org/web/20150924115331/http://www.ipcc.ch/pdf/special-reports/srccs/srccs_chapter7.pdf|archive-date=24 September 2015|url-status=dead}}</ref> Some carboxylic acid derivatives such as [[sodium salicylate]] are prepared using {{CO2}} by the [[Kolbe–Schmitt reaction]].<ref>{{cite book | vauthors = Morrison RT, Boyd RN |title= Organic Chemistry |edition=4th |publisher=Allyn and Bacon |year=1983 |isbn=978-0-205-05838-9 |pages=[https://archive.org/details/organicchemistry04morr/page/976 976–977] |url=https://archive.org/details/organicchemistry04morr/page/976}}</ref>

Captured {{CO2}} could be to produce [[methanol]] or [[electrofuel]]s. To be carbon-neutral, the {{CO2}} would need to come from bioenergy production or [[direct air capture]].<ref name="IEA-2020">IEA (2020), ''[https://www.iea.org/reports/ccus-in-clean-energy-transitions CCUS in Clean Energy Transitions]'', IEA, Paris [[File:CC-BY_icon.svg|50x50px]] Text was copied from this source, which is available under a [[creativecommons:by/4.0/|Creative Commons Attribution 4.0 International License]]</ref>{{Rp|page=|pages=21–24}}

=== Fossil fuel recovery ===
Carbon dioxide is used in [[enhanced oil recovery]] where it is injected into or adjacent to producing oil wells, usually under [[Supercritical fluid|supercritical]] conditions, when it becomes [[miscibility|miscible]] with the oil. This approach can increase original oil recovery by reducing residual oil saturation by 7–23% additional to [[Extraction of petroleum#Primary recovery|primary extraction]].<ref>{{cite book |url=http://www.globalccsinstitute.com/publications/accelerating-uptake-ccs-industrial-use-captured-carbon-dioxide |title=Accelerating the uptake of CCS: industrial use of captured carbon dioxide |date=20 December 2011 |website=Global CCS Institute |chapter=Appendix A: {{CO2}} for use in enhanced oil recovery (EOR) |access-date=2 January 2017 |chapter-url=http://hub.globalccsinstitute.com/publications/accelerating-uptake-ccs-industrial-use-captured-carbon-dioxide/appendix-co2-use |archive-url=https://web.archive.org/web/20170428013833/http://www.globalccsinstitute.com/publications/accelerating-uptake-ccs-industrial-use-captured-carbon-dioxide |archive-date=28 April 2017 |url-status=live}}</ref> It acts as both a pressurizing agent and, when dissolved into the underground [[crude oil]], significantly reduces its viscosity, and changing surface chemistry enabling the oil to flow more rapidly through the reservoir to the removal well.<ref>{{cite journal |vauthors=Austell JM |year=2005 |title={{CO2}} for Enhanced Oil Recovery Needs – Enhanced Fiscal Incentives |url=http://www.touchoilandgas.com/enhanced-recovery-needs-enhanced-a423-1.html |journal=Exploration & Production: The Oil & Gas Review |archive-url=https://web.archive.org/web/20120207071349/http://www.touchoilandgas.com/enhanced-recovery-needs-enhanced-a423-1.html |archive-date=7 February 2012 |access-date=28 September 2007}}</ref>

Most {{CO2}} injected in {{CO2}}-EOR projects comes from naturally occurring underground {{CO2}} deposits.<ref name="IEA-2019">{{Cite web |date=2019-04-11 |title=Can CO2-EOR really provide carbon-negative oil? – Analysis |url=https://www.iea.org/commentaries/can-co2-eor-really-provide-carbon-negative-oil |access-date=2024-10-16 |website=IEA |language=en-GB}} Text was copied from this source, which is available under a [[creativecommons:by/4.0/|Creative Commons Attribution 4.0 International License]]</ref> Some {{CO2}} used in EOR is captured from industrial facilities such as [[Natural-gas processing|natural gas processing plants]], using [[Carbon capture and storage|carbon capture]] technology and transported to the oilfield in pipelines.<ref name="IEA-2019" />

=== Agriculture ===
Plants require carbon dioxide to conduct photosynthesis. The atmospheres of greenhouses may (if of large size, must) be enriched with additional {{CO2}} to sustain and increase the rate of plant growth.<ref>{{cite web |url=http://www.ext.colostate.edu/mg/gardennotes/141.html |title=Plant Growth Factors: Photosynthesis, Respiration, and Transpiration |website=CMG GardenNotes | vauthors = Whiting D, Roll M, Vickerman L |publisher=Colorado Master Gardener Program |date=August 2010 |access-date=10 October 2011 |archive-url=https://web.archive.org/web/20140902192633/http://www.ext.colostate.edu/mg/gardennotes/141.html |archive-date=2 September 2014}}</ref><ref>{{cite book |chapter-url=http://www-formal.stanford.edu/jmc/nature/node21.html |chapter=Carbon dioxide |url=http://www-formal.stanford.edu/jmc/nature/nature.html |title=How Much Land Can Ten Billion People Spare for Nature? | vauthors = Waggoner PE |date=February 1994 |access-date=10 October 2011 |archive-date=12 October 2011 |archive-url=https://web.archive.org/web/20111012165809/http://www-formal.stanford.edu/jmc/nature/nature.html |url-status=live}}</ref> At very high concentrations (100 times atmospheric concentration, or greater), carbon dioxide can be toxic to animal life, so raising the concentration to 10,000&nbsp;ppm (1%) or higher for several hours will eliminate pests such as [[whiteflies]] and [[spider mite]]s in a greenhouse.<ref>{{cite journal | vauthors = Stafford N | title = Future crops: the other greenhouse effect | journal = Nature | volume = 448 | issue = 7153 | pages = 526–528 | date = August 2007 | pmid = 17671477 | doi = 10.1038/448526a | bibcode = 2007Natur.448..526S | s2cid = 9845813 | doi-access = free}}</ref> Some plants respond more favorably to rising carbon dioxide concentrations than others, which can lead to vegetation regime shifts like [[woody plant encroachment]].<ref>{{Citation |last1=Archer |first1=Steven R. |title=Woody Plant Encroachment: Causes and Consequences |date=2017 |work=Rangeland Systems |pages=25–84 |editor-last=Briske |editor-first=David D. |place=Cham |publisher=Springer International Publishing |language=en |doi=10.1007/978-3-319-46709-2_2 |isbn=978-3-319-46707-8 |last2=Andersen |first2=Erik M. |last3=Predick |first3=Katharine I. |last4=Schwinning |first4=Susanne |last5=Steidl |first5=Robert J. |last6=Woods |first6=Steven R.|doi-access=free }}</ref>

=== Foods ===
[[File:Soda bubbles macro.jpg|thumb|Carbon dioxide bubbles in a soft drink]]

Carbon dioxide is a [[food additive]] used as a propellant and acidity regulator in the food industry. It is approved for usage in the EU<ref>UK Food Standards Agency: {{cite web |url=http://www.food.gov.uk/safereating/chemsafe/additivesbranch/enumberlist |title=Current EU approved additives and their E Numbers |access-date=27 October 2011 |archive-date=7 October 2010 |archive-url=https://web.archive.org/web/20101007124435/http://www.food.gov.uk/safereating/chemsafe/additivesbranch/enumberlist |url-status=live}}</ref> (listed as [[E number]] E290), US,<ref>US Food and Drug Administration: {{cite web |url=https://www.fda.gov/food/ingredientspackaginglabeling/foodadditivesingredients/ucm091048.htm |title=Food Additive Status List |website=[[Food and Drug Administration]] |access-date=13 June 2015 |archive-date=4 November 2017 |archive-url=https://web.archive.org/web/20171104061606/https://www.fda.gov/Food/IngredientsPackagingLabeling/FoodAdditivesIngredients/ucm091048.htm |url-status=live}}</ref> Australia and New Zealand<ref>Australia New Zealand Food Standards Code{{cite web |url=http://www.comlaw.gov.au/Details/F2011C00827 |title=Standard 1.2.4 – Labelling of ingredients |date=8 September 2011 |access-date=27 October 2011 |archive-date=19 January 2012 |archive-url=https://web.archive.org/web/20120119082034/http://www.comlaw.gov.au/Details/F2011C00827 |url-status=live}}</ref> (listed by its [[INS number]] 290).

A candy called [[Pop Rocks]] is pressurized with carbon dioxide gas<ref>{{Cite book |url=https://books.google.com/books?id=0XeSJLflq90C&q=Pop+Rocks+is+pressurized+with+carbon+dioxide+gas&pg=PA7-IA3 |title=Futurific Leading Indicators Magazine |volume=1 |publisher=CRAES LLC |isbn=978-0-9847670-1-4 |access-date=9 November 2020 |archive-date=15 August 2021 |archive-url=https://web.archive.org/web/20210815224429/https://books.google.com/books?id=0XeSJLflq90C&q=Pop+Rocks+is+pressurized+with+carbon+dioxide+gas&pg=PA7-IA3 |url-status=live}}</ref> at about {{convert|4000|kPa|bar psi|abbr=on|lk=on}}. When placed in the mouth, it dissolves (just like other hard candy) and releases the gas bubbles with an audible pop.

[[Leavening agent]]s cause dough to rise by producing carbon dioxide.<ref>{{Cite book |url=https://books.google.com/books?id=2bmaCgAAQBAJ&q=Leavening+agents+cause+dough+to+rise+by+producing+carbon+dioxide&pg=PT29 |title=Indian Breads: A Comprehensive Guide to Traditional and Innovative Indian Breads |vauthors=Vijay GP |date=25 September 2015 |publisher=Westland |isbn=978-93-85724-46-6}}{{Dead link|date=August 2023 |bot=InternetArchiveBot |fix-attempted=yes}}</ref> [[Baker's yeast]] produces carbon dioxide by fermentation of sugars within the dough, while chemical leaveners such as [[baking powder]] and [[baking soda]] release carbon dioxide when heated or if exposed to [[acid]]s.

==== Beverages ====
Carbon dioxide is used to produce [[carbonation|carbonated]] [[soft drink]]s and [[soda water]]. Traditionally, the carbonation of beer and sparkling wine came about through natural fermentation, but many manufacturers carbonate these drinks with carbon dioxide recovered from the fermentation process. In the case of bottled and kegged beer, the most common method used is carbonation with recycled carbon dioxide. With the exception of British [[cask ale#Real ale|real ale]], draught beer is usually transferred from kegs in a cold room or cellar to dispensing taps on the bar using pressurized carbon dioxide, sometimes mixed with nitrogen.

The taste of soda water (and related taste sensations in other carbonated beverages) is an effect of the dissolved carbon dioxide rather than the bursting bubbles of the gas. [[Carbonic anhydrase&nbsp;4]] converts carbon dioxide to [[carbonic acid]] leading to a [[sour]] taste, and also the dissolved carbon dioxide induces a [[somatosensory]] response.<ref>{{cite web |url= https://www.sciencedaily.com/releases/2009/10/091015141510.htm |title= Scientists Discover Protein Receptor For Carbonation Taste |website= [[ScienceDaily]] |date= 16 October 2009 |access-date= 29 March 2020 |archive-date= 29 March 2020 |archive-url= https://web.archive.org/web/20200329042900/https://www.sciencedaily.com/releases/2009/10/091015141510.htm |url-status= live}}</ref>

==== Winemaking ====
[[File:Dry ice used to preserve grapes after harvest.jpg|thumb|Dry ice used to preserve grapes after harvest]]
Carbon dioxide in the form of [[dry ice]] is often used during the [[cold soak]] phase in [[winemaking]] to cool clusters of [[grape]]s quickly after picking to help prevent spontaneous [[Fermentation (wine)|fermentation]] by wild [[yeast (wine)|yeast]]. The main advantage of using dry ice over water ice is that it cools the grapes without adding any additional water that might decrease the sugar concentration in the [[grape must]], and thus the [[ethanol|alcohol]] concentration in the finished wine. Carbon dioxide is also used to create a hypoxic environment for [[carbonic maceration]], the process used to produce [[Beaujolais]] wine.

Carbon dioxide is sometimes used to top up wine bottles or other [[storage (wine)|storage]] vessels such as barrels to prevent oxidation, though it has the problem that it can dissolve into the wine, making a previously still wine slightly fizzy. For this reason, other gases such as [[nitrogen]] or [[argon]] are preferred for this process by professional wine makers.

====Stunning animals====
Carbon dioxide is often used to "stun" animals before slaughter.<ref>{{cite journal | vauthors = Coghlan A |title=A more humane way of slaughtering chickens might get EU approval |journal=New Scientist |date=3 February 2018 |url=https://www.newscientist.com/article/2159895-a-more-humane-way-of-slaughtering-chickens-might-get-eu-approval |access-date=24 June 2018 |archive-date=24 June 2018 |archive-url=https://web.archive.org/web/20180624204842/https://www.newscientist.com/article/2159895-a-more-humane-way-of-slaughtering-chickens-might-get-eu-approval/ |url-status=live}}</ref> "Stunning" may be a misnomer, as the animals are not knocked out immediately and may suffer distress.<ref>{{cite web |url=http://kb.rspca.org.au/What-is-CO2-stunning_118.html |archive-url=https://web.archive.org/web/20140409003755/http://kb.rspca.org.au/What-is-CO2-stunning_118.html |url-status=dead |archive-date=9 April 2014 |title=What is {{CO2}} stunning? |publisher=RSPCA}}</ref><ref name=Campbell>{{cite journal | vauthors = Campbell A |title=Humane execution and the fear of the tumbril |journal=New Scientist |date=10 March 2018 |url=https://www.newscientist.com/letter/mg23731680-900-humane-execution-and-the-fear-of-the-tumbril-3 |access-date=24 June 2018 |archive-date=24 June 2018 |archive-url=https://web.archive.org/web/20180624204708/https://www.newscientist.com/letter/mg23731680-900-humane-execution-and-the-fear-of-the-tumbril-3/ |url-status=live}}</ref>

=== Inert gas ===
Carbon dioxide is one of the most commonly used compressed gases for pneumatic (pressurized gas) systems in portable pressure tools. Carbon dioxide is also used as an atmosphere for [[welding]], although in the welding arc, it reacts to [[oxidation|oxidize]] most metals. Use in the automotive industry is common despite significant evidence that welds made in carbon dioxide are more [[brittle]] than those made in more inert atmospheres.<ref>{{Cite book |last=International |first=Petrogav |url=https://books.google.com/books?id=ZS7JDwAAQBAJ |title=Production Course for Hiring on Offshore Oil and Gas Rigs |publisher=Petrogav International |pages=214 |language=en}}</ref> When used for [[MIG welding]], {{CO2}} use is sometimes referred to as MAG welding, for Metal Active Gas, as {{CO2}} can react at these high temperatures. It tends to produce a hotter puddle than truly inert atmospheres, improving the flow characteristics. Although, this may be due to atmospheric reactions occurring at the puddle site. This is usually the opposite of the desired effect when welding, as it tends to embrittle the site, but may not be a problem for general mild steel welding, where ultimate ductility is not a major concern.

Carbon dioxide is used in many consumer products that require pressurized gas because it is inexpensive and nonflammable, and because it undergoes a phase transition from gas to liquid at room temperature at an attainable pressure of approximately {{convert|60|bar|psi atm|abbr=on|lk=on}}, allowing far more carbon dioxide to fit in a given container than otherwise would. Life jackets often contain canisters of pressured carbon dioxide for quick inflation. [[Aluminium]] capsules of {{CO2}} are also sold as supplies of compressed gas for [[air gun]]s, [[paintball]] markers/guns, inflating bicycle tires, and for making [[carbonated water]]. High concentrations of carbon dioxide can also be used to kill pests. Liquid carbon dioxide is used in [[supercritical drying]] of some food products and technological materials, in the preparation of specimens for [[scanning electron microscopy]]<ref name=Nordestgaard>{{cite journal | vauthors = Nordestgaard BG, Rostgaard J | title = Critical-point drying versus freeze drying for scanning electron microscopy: a quantitative and qualitative study on isolated hepatocytes | journal = Journal of Microscopy | volume = 137 | issue = Pt 2 | pages = 189–207 | date = February 1985 | pmid = 3989858 | doi = 10.1111/j.1365-2818.1985.tb02577.x | s2cid = 32065173}}</ref> and in the [[decaffeination]] of [[coffee bean]]s.

=== Fire extinguisher ===
[[File:US Army 53023 Fire Prevention Week.jpg|thumb|Use of a {{CO2}} fire extinguisher]]
Carbon dioxide can be used to extinguish flames by flooding the environment around the flame with the gas. It does not itself react to extinguish the flame, but starves the flame of oxygen by displacing it. Some [[Fire extinguisher#Halons, Halon-replacement clean agents and carbon dioxide|fire extinguishers]], especially those designed for [[electrical fire]]s, contain liquid carbon dioxide under pressure. Carbon dioxide extinguishers work well on small flammable liquid and electrical fires, but not on ordinary combustible fires, because they do not cool the burning substances significantly, and when the carbon dioxide disperses, they can catch fire upon exposure to [[atmospheric oxygen]]. They are mainly used in server rooms.<ref>{{Cite web |title=Types of Fire Extinguishers |url=https://www.firesafe.org.uk/types-use-and-colours-of-portable-fire-extinguishers/ |url-status=live |access-date=2021-06-28 |website=The Fire Safety Advice Centre |archive-date=28 June 2021 |archive-url=https://web.archive.org/web/20210628185630/https://www.firesafe.org.uk/types-use-and-colours-of-portable-fire-extinguishers/}}</ref>

Carbon dioxide has also been widely used as an extinguishing agent in fixed fire-protection systems for local application of specific hazards and total flooding of a protected space.<ref>National Fire Protection Association Code 12.</ref> [[International Maritime Organization]] standards recognize carbon dioxide systems for fire protection of ship holds and engine rooms. Carbon dioxide-based fire-protection systems have been linked to several deaths, because it can cause suffocation in sufficiently high concentrations. A review of {{CO2}} systems identified 51 incidents between 1975 and the date of the report (2000), causing 72 deaths and 145 injuries.<ref>Carbon Dioxide as a Fire Suppressant: Examining the Risks, US EPA. 2000.</ref>

=== Supercritical {{CO2}} as solvent ===
{{See also|Supercritical carbon dioxide|Green chemistry}}

Liquid carbon dioxide is a good [[solvent]] for many [[lipophilic]] [[organic compound]]s and is used to [[decaffeinate]] [[coffee]].<ref name="Tsotsas">{{cite book |url=https://books.google.com/books?id=5210HQIwxzsC&pg=PA185 |title=Modern drying technology |vauthors=Tsotsas E, Mujumdar AS |date=2011 |publisher=John Wiley & Sons |isbn=978-3-527-31558-1 |series=Vol. 3: Product quality and formulation |access-date=3 December 2019 |archive-url=https://web.archive.org/web/20200321173739/https://books.google.com/books?id=5210HQIwxzsC&pg=PA185 |archive-date=21 March 2020 |url-status=live}}</ref> Carbon dioxide has attracted attention in the [[pharmaceutical]] and other chemical processing industries as a less toxic alternative to more traditional solvents such as [[organochloride]]s. It is also used by some [[dry cleaners]] for this reason. It is used in the preparation of some [[Aerogel#Production|aerogels]] because of the properties of supercritical carbon dioxide.

=== Refrigerant ===
{{see also|Refrigerant|Sustainable automotive air conditioning}}
[[File:Comparison carbon dioxide water phase diagrams.svg|thumb|upright=2|Comparison of the pressure–temperature phase diagrams of carbon dioxide (red) and water (blue) as a log-lin chart with phase transitions points at 1 atmosphere]]

Liquid and solid carbon dioxide are important [[refrigerant]]s, especially in the food industry, where they are employed during the transportation and storage of ice cream and other frozen foods. Solid carbon dioxide is called "dry ice" and is used for small shipments where refrigeration equipment is not practical. Solid carbon dioxide is always below {{convert|-78.5|C|F}} at regular atmospheric pressure, regardless of the air temperature.

{{anchor|R744}} Liquid carbon dioxide (industry nomenclature R744 or R-744) was used as a refrigerant prior to the use of [[dichlorodifluoromethane]] (R12, a [[chlorofluorocarbon]] (CFC) compound).<ref>{{Cite web |last=Pearson |first=S. Forbes |title=Refrigerants Past, Present and Future |url=http://www.r744.com/files/pdf_597.pdf |url-status=dead |archive-url=https://web.archive.org/web/20180713171048/http://www.r744.com/files/pdf_597.pdf |archive-date=2018-07-13 |access-date=2021-03-30 |website=R744}}</ref> {{CO2}} might enjoy a renaissance because one of the main substitutes to CFCs, [[1,1,1,2-tetrafluoroethane]] ([[R134a]], a [[hydrofluorocarbon]] (HFC) compound) contributes to [[climate change]] more than {{CO2}} does. {{CO2}} physical properties are highly favorable for cooling, refrigeration, and heating purposes, having a high volumetric cooling capacity. Due to the need to operate at pressures of up to {{convert|130|bar|psi kPa}}, {{CO2}} systems require highly mechanically resistant reservoirs and components that have already been developed for mass production in many sectors. In automobile air conditioning, in more than 90% of all driving conditions for latitudes higher than 50°, {{CO2}} (R744) operates more efficiently than systems using HFCs (e.g., R134a). Its environmental advantages ([[Global warming potential|GWP]] of 1, non-ozone depleting, non-toxic, non-flammable) could make it the future working fluid to replace current HFCs in cars, supermarkets, and heat pump water heaters, among others. [[Coca-Cola]] has fielded {{CO2}}-based beverage coolers and the [[United States Army|U.S. Army]] is interested in {{CO2}} refrigeration and heating technology.<ref name="ccref1">{{cite web |url=http://www.coca-colacompany.com/cooling-equipment-pushing-forward-with-hfc-free |title=The Coca-Cola Company Announces Adoption of HFC-Free Insulation in Refrigeration Units to Combat Global Warming |access-date=11 October 2007 |date=5 June 2006 |publisher=The Coca-Cola Company |archive-date=1 November 2013 |archive-url=https://web.archive.org/web/20131101195654/http://www.coca-colacompany.com/cooling-equipment-pushing-forward-with-hfc-free |url-status=live}}</ref><ref name="usforces">{{cite news|title = Modine reinforces its {{CO2}} research efforts|url = http://www.r744.com/news/news_ida145.php|archive-url = https://web.archive.org/web/20080210194203/http://www.r744.com/news/news_ida145.php|url-status = dead|archive-date = 10 February 2008|date = 28 June 2007|publisher = R744.com}}</ref>

=== Minor uses ===
[[File:Carbon Dioxide Laser At The Laser Effects Test Facility.jpg|thumb|right|upright=1.35|A [[carbon-dioxide laser]]]]
Carbon dioxide is the [[active laser medium|lasing medium]] in a [[carbon-dioxide laser]], which is one of the earliest type of lasers.

Carbon dioxide can be used as a means of controlling the [[pH]] of swimming pools,<ref>{{Cite book |url=https://books.google.com/books?id=IWpWAAAAMAAJ&q=%C2%A0%C2%A0Carbon+dioxide+can+be+used+as+a+means+of+controlling+the+pH+of+swimming+pool |title=TCE, the Chemical Engineer |date=1990 |publisher=Institution of Chemical Engineers |access-date=2 June 2020 |archive-date=17 August 2021 |archive-url=https://web.archive.org/web/20210817030754/https://books.google.com/books?id=IWpWAAAAMAAJ&q=%C2%A0%C2%A0Carbon+dioxide+can+be+used+as+a+means+of+controlling+the+pH+of+swimming+pool |url-status=live}}</ref> by continuously adding gas to the water, thus keeping the pH from rising. Among the advantages of this is the avoidance of handling (more hazardous) acids. Similarly, it is also used in the maintaining [[Reef aquarium|reef aquaria]], where it is commonly used in [[calcium reactor]]s to temporarily lower the pH of water being passed over [[calcium carbonate]] in order to allow the calcium carbonate to dissolve into the water more freely, where it is used by some [[coral]]s to build their skeleton.

Used as the primary coolant in the British [[advanced gas-cooled reactor]] for nuclear power generation.

Carbon dioxide induction is commonly used for the euthanasia of laboratory research animals. Methods to administer {{CO2}} include placing animals directly into a closed, prefilled chamber containing {{CO2}}, or exposure to a gradually increasing concentration of {{CO2}}. The [[American Veterinary Medical Association]]'s 2020 guidelines for carbon dioxide induction state that a displacement rate of 30–70% of the chamber or cage volume per minute is optimal for the humane euthanasia of small rodents.<ref name=avma>{{cite web |url=https://www.avma.org/kb/policies/documents/euthanasia.pdf |title=AVMA guidelines for the euthanasia of animals: 2020 Edition |date=2020 |publisher=[[American Veterinary Medical Association]] |access-date=August 13, 2021 |archive-date=1 February 2014 |archive-url=https://web.archive.org/web/20140201174132/https://www.avma.org/KB/Policies/Documents/euthanasia.pdf |url-status=live}}</ref>{{Rp|5, 31}} Percentages of {{CO2}} vary for different species, based on identified optimal percentages to minimize distress.<ref name=avma />{{Rp|22}}

Carbon dioxide is also used in several related [[carbon dioxide cleaning|cleaning and surface-preparation]] techniques.