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{{short description|Deliberate and large-scale intervention in the Earth’s climate system}}
{{Redirect|Geoengineering}}
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'''Climate engineering''', or commonly '''geoengineering''', is the deliberate and large-scale intervention in the Earth's [[climate system]].<ref name=":3">{{Cite book|url=https://www.worldcat.org/oclc/436232805|title=Geoengineering the climate : science, governance and uncertainty|date=2009|publisher=Royal Society|others=Royal Society|isbn=9780854037735|location=London|oclc=436232805|access-date=2021-06-07|archive-date=2020-06-07|archive-url=https://web.archive.org/web/20200607212213/https://www.worldcat.org/title/geoengineering-the-climate-science-governance-and-uncertainty/oclc/436232805|url-status=live}}</ref> The main categories of climate engineering are [[solar geoengineering]] and [[carbon dioxide removal]].{{Contradict-inline|reason=Carbon dioxide removal#Definitions says CDR is not climate engineering|date=November 2021}} Solar geoengineering, or solar radiation modification, would reflect some [[Solar irradiance|sunlight (solar radiation)]] back to space to limit or reverse human-caused [[Global warming|climate change]]. Carbon dioxide removal refers to removing [[carbon dioxide]] gas from the atmosphere and [[carbon sequestration|sequestering]] it for long periods of time. The difference between the two is sometimes described as solar geoengineering modifying the planet's [[shortwave radiation]] budget and carbon dioxide removal modifying its [[Outgoing longwave radiation|longwave radiation]] budget.

Climate engineering approaches are sometimes viewed as potential complementary options for limiting [[climate change]] or its impacts, alongside reducing [[greenhouse gas emissions]] and [[adaptation to global warming|adaptation]].<ref name=":3" /> There is substantial agreement among scientists that solar geoengineering and carbon dioxide removal cannot substitute for reducing emissions. Given that all types of measures for [[addressing climate change]] have economic, political, or physical limitations,<ref name="lenton09">{{cite journal | doi=10.5194/acp-9-5539-2009 | last=Lenton | first=T.M. | author2=Vaughan, N.E. | year=2009 | title=The radiative forcing potential of different climate geoengineering options | journal=[[Atmospheric Chemistry and Physics]] | volume=9 | issue=15 | pages=5539–5561 | bibcode=2009ACP.....9.5539L | url=http://www.atmos-chem-phys.net/9/5539/2009/acp-9-5539-2009.html | doi-access=free | access-date=2009-09-04 | archive-date=2019-12-14 | archive-url=https://web.archive.org/web/20191214043800/https://www.atmos-chem-phys.net/9/5539/2009/acp-9-5539-2009.html | url-status=live }}</ref><ref name="imeche09">{{cite web|url=http://www.imeche.org/Libraries/Key_Themes/IMechEGeoengineeringReport.sflb.ashx|archive-url=https://web.archive.org/web/20110722191723/http://www.imeche.org/Libraries/Key_Themes/IMechEGeoengineeringReport.sflb.ashx|archive-date=2011-07-22|url-status=dead|title=Geo-engineering{{Snd}} Giving us the time to act?|publisher=I Mech E|access-date=2011-03-12}}</ref> some climate engineering approaches might eventually be used as part of an ensemble of responses, which could have the objective of [[climate restoration]].<ref name="Royal Society Policy Document">{{cite report|url=http://royalsociety.org/uploadedFiles/Royal_Society_Content/policy/publications/2009/8693.pdf|title=Geoengineering the Climate: Science, Governance and Uncertainty|author=Working group|date=2009|publisher=The Royal Society|location=London|page=1|isbn=978-0-85403-773-5|id=RS1636|access-date=2011-12-01|archive-date=2014-03-12|archive-url=https://web.archive.org/web/20140312031514/http://royalsociety.org/uploadedfiles/royal_society_content/policy/publications/2009/8693.pdf|url-status=live}}</ref>

Although there are the large uncertainties over effectiveness and [[side effect]]s and [[unforeseen consequences]], most experts argue that the risks of such interventions must be seen in the context of risks of dangerous climate change.<ref name="perspectives">{{cite book
|year=2012
|title=Climate Engineering{{Snd}} Avoiding Pandora's Box through Research and Governance.
|publisher=Fridtjof Nansen Institute (FNI), Perspectives
|series=FNI Climate Policy Perspectives
|author1=Matthias Honegger
|author2=Axel Michaelowa
|author3=Sonja Butzengeiger-Geyer
|url=https://www.fni.no/doc&pdf/FNI-Climate-Policy-Perspectives-5.pdf
|archive-url=https://web.archive.org/web/20150906055338/https://www.fni.no/doc%26pdf/FNI-Climate-Policy-Perspectives-5.pdf
|url-status=dead
|archive-date=2015-09-06
|access-date=2018-10-09
}}</ref><ref>{{cite web |url=https://insideclimatenews.org/news/04102016/climate-change-removing-carbon-dioxide-air-james-hansen-2-degrees-paris-climate-agreement-global-warming |title=Removing CO2 From the Air Only Hope for Fixing Climate Change, New Study Says; Without 'negative emissions' to help return atmospheric CO2 to 350 ppm, future generations could face costs that 'may become too heavy to bear,' paper says. |author=Zahra Hirji |date=October 6, 2016 |website=insideclimatenews.org |publisher=[[InsideClimate News]] |access-date=October 7, 2016 |archive-date=November 17, 2019 |archive-url=https://web.archive.org/web/20191117214634/https://insideclimatenews.org/news/04102016/climate-change-removing-carbon-dioxide-air-james-hansen-2-degrees-paris-climate-agreement-global-warming |url-status=live }}</ref> Interventions at large scale may run a greater risk of disrupting natural systems resulting in a dilemma that those approaches that could prove highly cost-effective in addressing extreme climate risk, might themselves cause substantial risk.<ref name="perspectives" /> Some have suggested that the concept of engineering the climate could reduce political and public pressure for emissions reduction, which could exacerbate overall climate risks; others assert that the threat of climate engineering could spur emissions cuts.<ref>{{cite web | url=http://www.irgc.org/geoengineering | title=Geoengineering | publisher=[[International Risk Governance Council]] | access-date=2009-10-07 | year=2009 | archive-url=https://web.archive.org/web/20091203132630/http://www.irgc.org/geoengineering | archive-date=2009-12-03 | url-status=dead }}</ref><ref>{{Cite journal|title = A critical examination of the climate engineering moral hazard and risk compensation concern|journal = The Anthropocene Review|date = 2015-08-01|issn = 2053-0196|pages = 174–191|volume = 2|issue = 2|doi = 10.1177/2053019614554304|first = Jesse|last = Reynolds|s2cid = 59407485}}</ref><ref>{{Cite journal|title = Ethical aspects of the mitigation obstruction argument against climate engineering research|journal = Philosophical Transactions of the Royal Society of London A: Mathematical, Physical and Engineering Sciences|date = 2014-12-28|issn = 1364-503X|pmid = 25404676|pages = 20140062|volume = 372|issue = 2031|doi = 10.1098/rsta.2014.0062|first = David R.|last = Morrow|bibcode = 2014RSPTA.37240062M |doi-access = free}}</ref>

==Solar geoengineering==
{{Main|Solar geoengineering}}
{{Short description|Reflection of sunlight to reduce global warming}}
[[File:SPICE_SRM_overview.jpg|alt=refer to caption and image description|right|thumb|320x320px|Proposed solar geoengineering using a tethered balloon to inject sulfate aerosols into the stratosphere.]]
Solar geoengineering would deflect sunlight away from the Earth, or increase the reflectivity ([[albedo]]) of the atmosphere or the Earth's surface. These methods are not a substitute for [[climate change mitigation]] because they would not reduce [[greenhouse gas]] concentrations in the [[atmosphere]], and thus would not address [[ocean acidification]] caused by [[CO2|carbon dioxide]].<ref>{{Cite book|last=NASEM|url=https://www.nap.edu/catalog/18988/climate-intervention-reflecting-sunlight-to-cool-earth|title=Climate Intervention: Reflecting Sunlight to Cool Earth|date=2015|publisher=National Academies Press|isbn=978-0-309-31482-4|doi=10.17226/18988|language=en|access-date=2018-08-20|archive-date=2019-12-14|archive-url=https://web.archive.org/web/20191214192318/http://www.nap.edu/catalog.php?record_id=18988|url-status=live}}</ref> In general, solar geoengineering projects presently appear able to take effect rapidly and be reversible in their direct climatic effects. The [[National Academies of Sciences, Engineering, and Medicine|US National Academy of Sciences, Engineering, and Medicine]] states in a 2021 report: "The available research indicates that SG could reduce surface temperatures and potentially ameliorate some risks posed by climate change (e.g., to avoid crossing critical climate “tipping points”; to reduce harmful impacts of weather extremes)."<ref name=":02">{{Cite book|last=National Academies of Sciences|first=Engineering|url=https://www.nap.edu/catalog/25762/reflecting-sunlight-recommendations-for-solar-geoengineering-research-and-research-governance|title=Reflecting Sunlight: Recommendations for Solar Geoengineering Research and Research Governance|date=2021-03-25|isbn=978-0-309-67605-2|language=en|doi=10.17226/25762|s2cid=234327299|access-date=2021-04-17|archive-date=2021-04-17|archive-url=https://web.archive.org/web/20210417055338/https://www.nap.edu/catalog/25762/reflecting-sunlight-recommendations-for-solar-geoengineering-research-and-research-governance|url-status=live}}</ref>

Solar geoengineering methods<ref name="Royal Society Policy Document" /> may include:
* [[Stratospheric aerosol injection]], in which small particles would be injected into the upper atmosphere;
*[[Cloud reflectivity modification|Marine cloud brightening]], which would spray fine [[sea water]] to whiten clouds and thus increase cloud reflectivity; and 
* [[Cirrus cloud thinning]], which is strictly not solar geoengineering but shares many of the physical and especially governance characteristics of the other methods.<ref>{{Cite book|last1=Committee on Developing a Research Agenda and Research Governance Approaches for Climate Intervention Strategies that Reflect Sunlight to Cool Earth|url=https://www.nap.edu/catalog/25762|title=Reflecting Sunlight: Recommendations for Solar Geoengineering Research and Research Governance|last2=Board on Atmospheric Sciences and Climate|last3=Committee on Science, Technology, and Law|last4=Division on Earth and Life Studies|last5=Policy and Global Affairs|last6=National Academies of Sciences, Engineering, and Medicine|date=2021-05-28|publisher=National Academies Press|isbn=978-0-309-67605-2|location=Washington, D.C.|doi=10.17226/25762|s2cid=234327299}}</ref>
Solar geoengineering requires relatively large scale implementation in order to impact the Earth's climate. The least costly proposals are estimated at tens of billions of US dollars annually in direct deployment costs.<ref name="Climate Intervention">{{Cite book|author=National Research Council<!--|last2 = Impacts|first2 = Committee on Geoengineering Climate: Technical Evaluation Discussion of|last3 = Division On Earth And Life Studies|first3 = National Research Council (U.S.)|last4 = Ocean Studies Board|first4 = National Research Council (U.S.)|last5 = Climate|first5 = Board on Atmospheric Sciences-->|title=Climate Intervention: Reflecting Sunlight to Cool Earth|date=2017|publisher=The National Academies Press|isbn=978-0-309-31482-4|doi=10.17226/18988}} Ebook: {{ISBN|978-0-309-31485-5}}.</ref> This is low enough that it might be in the interests of several single countries to implement them unilaterally.{{Citation needed|date=May 2021}} Solar geoengineering may pose novel significant risks such as regional climate disruptions.

==Carbon dioxide removal==
{{Main|Carbon dioxide removal||}}
{{Off topic|date=November 2019|Carbon dioxide removal|talksectionheading}}
[[File:Tree_planting_closeup.jpg|thumb|upright|Planting trees is a means of carbon dioxide removal.]]
Carbon dioxide removal (sometimes known as negative emissions technologies) includes methods that directly remove such gases from the atmosphere and those that promote natural processes that draw down and sequester carbon dioxide.<ref name=":0">{{Cite book|title=Negative Emissions Technologies and Reliable Sequestration: A Research Agenda|publisher=National Academies of Sciences, Engineering, and Medicine|year=2019|isbn=978-0-309-48452-7|location=Washington, DC|page=23|language=en|doi=10.17226/25259|pmid=31120708|last1=National Academies Of Sciences|first1=Engineering|s2cid=134196575}}</ref> Some methods overlap with [[carbon capture and storage]]. Carbon dioxide removal may not be considered to be climate engineering by all commentators because it is not necessarily large scale.<ref name=":0" /> Techniques in this category include:
* [[Bio-energy with carbon capture and storage|Bioenergy with carbon capture and storage]] to sequester carbon and simultaneously provide energy
* [[Direct air capture]] to remove carbon dioxide from ambient air
* [[Afforestation]], [[reforestation]] and [[forest restoration]] to absorb carbon dioxide
*Creating [[biochar]] (i.e. in biomass-fired thermal power plants), for mixing into the soil to create [[terra preta]]

Many of the [[IPCC]] model projections to keep global mean temperature rise below 1.5 and 2&nbsp;°C are based on the assumed large-scale deployment of carbon dioxide removal.<ref>{{cite web|url=https://www.carbonbrief.org/in-depth-experts-assess-the-feasibility-of-negative-emissions|title=In-depth: Experts assess the feasibility of 'negative emissions'|year=2016|publisher=CarbonBrief|access-date=2018-08-20|archive-date=2019-09-26|archive-url=https://web.archive.org/web/20190926010138/https://www.carbonbrief.org/in-depth-experts-assess-the-feasibility-of-negative-emissions|url-status=live}}</ref> Most carbon dioxide removal methods are presently expensive. Carbon dioxide removal techniques are typically slow to act, expensive, and entail risks that are relatively familiar, such as the risk of carbon dioxide leakage from underground storage formations. Carbon dioxide removal, like greenhouse gas emissions reductions, has impacts proportional to their scale. In other words, these techniques would not be "implemented" in the same sense as solar geoengineering ones.

==Issues==
=== Moral hazard or risk compensation ===
The existence of such techniques may reduce the political and social impetus to reduce carbon emissions.<ref name="Extreme action guardian"/> This has generally been called a potential [[moral hazard]], although [[risk compensation]] may be a more accurate term. This concern causes many environmental groups and campaigners to be reluctant to advocate or discuss climate engineering for fear of reducing the imperative to cut greenhouse gas emissions.<ref name="Moral hazard">{{cite web|url=http://www.celsias.com/article/geo-engineering-a-moral-hazard/|title=Geo-Engineering{{Snd}} a Moral Hazard|date=14 November 2007|publisher=celsias.com|access-date=9 September 2010|archive-url=https://web.archive.org/web/20110114085045/http://www.celsias.com/article/geo-engineering-a-moral-hazard/|archive-date=14 January 2011|url-status=dead|df=dmy-all}}</ref> However, several public opinion surveys and focus groups have found evidence of either assertions of a desire to increase emission cuts in the face of climate engineering, or of no effect.<ref name="Royal Society Policy Document"/><ref>{{cite report |author=[[Ipsos MORI]] |date=August 2010 |title=Experiment Earth? Report on a Public Dialogue on Geoengineering |url=https://www.ipsos.com/sites/default/files/publication/1970-01/sri_experiment-earth-report-on-a--public-dialogue-on-geoengineering_sept2010.pdf |access-date=2019-02-14 |archive-date=2019-02-15 |archive-url=https://web.archive.org/web/20190215050427/https://www.ipsos.com/sites/default/files/publication/1970-01/sri_experiment-earth-report-on-a--public-dialogue-on-geoengineering_sept2010.pdf |url-status=live }}</ref><ref>{{Cite journal|title = Public understanding of solar radiation management{{Snd}} IOPscience|date = 2011-12-01|doi = 10.1088/1748-9326/6/4/044006|first1 = A M|last1 = Mercer|first2 = D W|last2 = Keith|first3 = J D|last3 = Sharp|volume = 6|issue = 4|journal = Environmental Research Letters|pages = 044006|bibcode = 2011ERL.....6d4006M|url = https://dash.harvard.edu/bitstream/handle/1/12763597/53098873.pdf?sequence=1|doi-access = free|access-date = 2019-09-04|archive-date = 2019-03-31|archive-url = https://web.archive.org/web/20190331144301/https://dash.harvard.edu/bitstream/handle/1/12763597/53098873.pdf?sequence=1|url-status = live}}</ref><ref>{{Cite journal|title = Geoengineering and Climate Change Polarization Testing a Two-Channel Model of Science Communication|journal = The Annals of the American Academy of Political and Social Science|date = 2015-03-01|issn = 0002-7162|pages = 192–222|volume = 658|issue = 1|doi = 10.1177/0002716214559002|first1 = Dan M.|last1 = Kahan|first2 = Hank|last2 = Jenkins-Smith|first3 = Tor|last3 = Tarantola|first4 = Carol L.|last4 = Silva|first5 = Donald|last5 = Braman|s2cid = 149147565}}</ref><ref>{{Cite report|title=Views about geoengineering: Key findings from public discussion groups|publisher=Integrated Assessment of Geoengineering Proposals|date=2014-07-31|url=http://iagp.ac.uk/sites/default/files/Views%20about%20geoengineering%20IAGP.pdf|access-date=2018-08-20|archive-date=2016-12-23|archive-url=https://web.archive.org/web/20161223100051/http://iagp.ac.uk/sites/default/files/Views%20about%20geoengineering%20IAGP.pdf|url-status=live}}</ref><ref>{{Cite journal|title = Questioning the technological fix to climate change{{Snd}} Lay sense-making of geoengineering in Sweden|url =http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-119732|journal = Energy Research & Social Science|date = 2015-05-01|pages = 23–30|volume = 7|doi = 10.1016/j.erss.2015.03.001|first1 = Victoria|last1 = Wibeck|first2 = Anders|last2 = Hansson|first3 = Jonas|last3 = Anshelm}}</ref><ref>{{Cite journal|title = Exploring public perceptions of stratospheric sulfate injection|journal = Climatic Change|date = 2015-02-10|issn = 0165-0009|pages = 299–312|volume = 130|issue = 2|doi = 10.1007/s10584-014-1317-7|bibcode = 2015ClCh..130..299M|first1 = Christine|last1 = Merk|first2 = Gert|last2 = Pönitzsch|first3 = Carola|last3 = Kniebes|first4 = Katrin|last4 = Rehdanz|first5 = Ulrich|last5 = Schmidt|s2cid = 154196324}}</ref> Other modelling work suggests that the threat of climate engineering may in fact increase the likelihood of emissions reduction.<ref name="doi10.1007/s10584-011-0102-0">{{Cite journal | last1 = Millard-Ball | first1 = A. | title = The Tuvalu Syndrome | doi = 10.1007/s10584-011-0102-0 | journal = Climatic Change | volume = 110 | issue = 3–4 | pages = 1047–1066 | year = 2011 | s2cid = 153990911 }}</ref><ref>{{Cite journal|title = Geoengineering and global warming: a strategic perspective|journal = International Environmental Agreements: Politics, Law and Economics|date = 2012-02-10|issn = 1567-9764|pages = 375–389|volume = 12|issue = 4|doi = 10.1007/s10784-012-9167-0|first = Johannes|last = Urpelainen|s2cid = 154422202}}</ref><ref>{{Cite journal|title = The Intergenerational Transfer of Solar Radiation Management Capabilities and Atmospheric Carbon Stocks|journal = Environmental and Resource Economics|date = 2013-03-20|issn = 0924-6460|pages = 85–104|volume = 56|issue = 1|doi = 10.1007/s10640-013-9647-x|first1 = Timo|last1 = Goeschl|first2 = Daniel|last2 = Heyen|first3 = Juan|last3 = Moreno-Cruz|hdl = 10419/127358|s2cid = 52213135|url = http://archiv.ub.uni-heidelberg.de/volltextserver/14373/1/goeschl_heyen_moreno_cruz__2013_dp540.pdf|access-date = 2019-08-16|archive-date = 2020-12-04|archive-url = https://web.archive.org/web/20201204163528/http://archiv.ub.uni-heidelberg.de/volltextserver/14373/1/goeschl_heyen_moreno_cruz__2013_dp540.pdf|url-status = live}}</ref><ref>{{Cite journal|title = Mitigation and the geoengineering threat|journal = Resource and Energy Economics|date = 2015-08-01|pages = 248–263|volume = 41|doi = 10.1016/j.reseneeco.2015.06.001|first = Juan B.|last = Moreno-Cruz}}</ref>

In 2021, the IPCC said that emission pathways that limit globally averaged warming to 1.5&nbsp;°C or 2&nbsp;°C by the year 2100 assume the use of CDR (Carbon Dioxide Removal) approaches in combination with emission reductions.<ref>Page 4-81, [[IPCC Sixth Assessment Report]] Working Group 1, 9/8/21, https://www.ipcc.ch/2021/08/09/ar6-wg1-20210809-pr/ {{Webarchive|url=https://web.archive.org/web/20210811070140/https://www.ipcc.ch/2021/08/09/ar6-wg1-20210809-pr/ |date=2021-08-11 }}</ref>

===Politics===
Some environmental organizations have been reluctant to endorse or oppose (such as [[Friends of the Earth]]<ref name="Extreme action guardian">{{cite news|last=Adam|first=David|date=1 September 2008|title=Extreme and risky action the only way to tackle global warming, say scientists|work=The Guardian|url=https://www.theguardian.com/environment/2008/sep/01/climatechange.scienceofclimatechange2|access-date=2009-05-23|archive-date=2019-08-06|archive-url=https://web.archive.org/web/20190806230902/https://www.theguardian.com/environment/2008/sep/01/climatechange.scienceofclimatechange2|url-status=live}}</ref> and [[Greenpeace]]<ref name="Geoengineering no solution">{{cite news|last=Parr|first=Doug|date=1 September 2008|title=Geo-engineering is no solution to climate change|work=Guardian Newspaper|location=London|url=https://www.theguardian.com/environment/2008/sep/01/climatechange.scienceofclimatechange1|access-date=2009-05-23|archive-date=2018-08-20|archive-url=https://web.archive.org/web/20180820234933/https://www.theguardian.com/environment/2008/sep/01/climatechange.scienceofclimatechange1|url-status=live}}</ref>) solar geoengineering but are often more supportive of some nature-based carbon dioxide removal projects, such as afforestation and [[peatland restoration]]. Some commentators appear fundamentally opposed. The [[ETC Group (AGETC)|ETC Group]]<ref name="ETC">{{Cite web|title=Climate & Geoengineering|url=http://www.etcgroup.org/issues/climate-geoengineering|website=ETC Group|access-date=2018-08-20|archive-date=2018-08-21|archive-url=https://web.archive.org/web/20180821031630/http://www.etcgroup.org/issues/climate-geoengineering|url-status=live}}</ref> has called for a moratorium on climate engineering techniques.

It has been argued that regardless of the economic, scientific, and technical aspects, the difficulty of achieving concerted political action on global warming requires other approaches.<ref>{{cite news | url=https://www.theguardian.com/commentisfree/cifamerica/2008/dec/12/environment-climate-change-poznan | work=The Guardian | location=London | title=Let's get real on the environment | date=2008-12-12 | access-date=2010-03-30 | first=David | last=Appell | archive-date=2013-09-05 | archive-url=https://web.archive.org/web/20130905080720/http://www.theguardian.com/commentisfree/cifamerica/2008/dec/12/environment-climate-change-poznan | url-status=live }}</ref> Those arguing political expediency say the difficulty of achieving meaningful emissions cuts<ref>{{cite news | url=https://www.nytimes.com/2007/10/24/opinion/24caldiera.html?_r=2&ref=opinion&oref=slogin | work=The New York Times | title=How to Cool the Globe | first=Ken | last=Caldeira | author-link=Ken Caldeira | date=2007-10-24 | access-date=2010-03-30 | archive-date=2013-06-02 | archive-url=https://web.archive.org/web/20130602214921/http://www.nytimes.com/2007/10/24/opinion/24caldiera.html?_r=2&ref=opinion&oref=slogin | url-status=live }}</ref> and the effective failure of the [[Kyoto Protocol]] demonstrate the practical difficulties of achieving carbon dioxide emissions reduction by the agreement of the [[international community]].<ref name="Extreme action guardian" /> However, others point to support for climate engineering proposals among think tanks with a history of opposition to emissions reductions as evidence that, rather than climate engineering being a solution to the difficulties of emissions reductions, the prospect of climate engineering is being used as part of an argument to stall emissions reductions in the first place.<ref>{{cite web |url=http://www.worldchanging.com/archives/009784.html |title=Evaluation + Tools + Best Practices: Geoengineering and the New Climate Denialism |publisher=Worldchanging |access-date=2012-09-06 |archive-url=https://web.archive.org/web/20120828195432/http://www.worldchanging.com/archives/009784.html |archive-date=2012-08-28 |url-status=dead }}</ref>

===Ethics and responsibility===
Climate engineering would represent a large-scale, intentional effort to modify the climate. It would differ from activities such as burning fossil fuels, as those change the climate inadvertently. Intentional climate change is often viewed differently from a moral standpoint.<ref>{{cite journal | last1 = Bodansky | first1 = D | year = 1996 | title = May we engineer the climate? | journal = [[Climatic Change]] | volume = 33 | issue = 3| pages = 309–321 | doi=10.1007/bf00142579 | bibcode=1996ClCh...33..309B| s2cid = 156701681 }}</ref> It raises questions of whether humans have the right to change the climate deliberately, and under what conditions. For example, there may be an ethical distinction between climate engineering to minimize global warming and doing so to optimize the climate. Furthermore, ethical arguments often confront larger considerations of worldview, including individual and social-religious commitments. This may imply that discussions of climate engineering should reflect on how religious commitments might influence the discourse.<ref>{{cite journal | last1 = Clingerman | first1 = F. | last2 = O'Brien | first2 = K. | year = 2014 | title = Playing God: why religion belongs in the climate engineering debate | journal = [[Bulletin of the Atomic Scientists]] | volume = 70 | issue = 3| pages = 27–37 | doi=10.1177/0096340214531181| bibcode = 2014BuAtS..70c..27C | s2cid = 143742343 }}</ref> For many people, religious beliefs are pivotal in defining the role of human beings in the wider world. Some religious communities might claim that humans have no responsibility in managing the climate, instead seeing such world systems as the exclusive domain of a Creator. In contrast, other religious communities might see the human role as one of "stewardship" or benevolent management of the world.<ref>Clingerman, F. (2012) "Between Babel and Pelagius: Religion, Theology and Geoengineering," in Preston, C. (ed.), ''Engineering the Climate: The Ethics of Solar Radiation Management''. Lantham, MD: Lexington, pp. 201–219.</ref> The question of ethics also relates to issues of policy decision-making. For example, the selection of a globally agreed target temperature is a significant problem in any climate engineering [[governance]] regime, as different countries or interest groups may seek different global temperatures.<ref name="geoengineering_option">Victor, D. G., M. G. Morgan, J. Apt, J. Steinbruner, K. Ricke (2009) "The Geoengineering Option: A last resort against global warming?" ''[[Foreign Affairs]]'', March/April 2009</ref>

One of the lesser focused aspects of climate engineering is the role it can play in global inequality [[Environmental justice|(Environmental Justice)]]. Emissions are largely concentrated in a relatively few companies.<ref>{{Cite news|last=Riley|first=Tess|date=2017-07-10|title=Just 100 companies responsible for 71% of global emissions, study says|language=en-GB|work=The Guardian|url=https://www.theguardian.com/sustainable-business/2017/jul/10/100-fossil-fuel-companies-investors-responsible-71-global-emissions-cdp-study-climate-change|access-date=2021-02-12|issn=0261-3077|archive-date=2021-01-18|archive-url=https://web.archive.org/web/20210118063050/https://www.theguardian.com/sustainable-business/2017/jul/10/100-fossil-fuel-companies-investors-responsible-71-global-emissions-cdp-study-climate-change|url-status=live}}</ref> In not addressing the issue or changing practices to emit less, they directly receive benefit from the damage they cause to the climate. In a similar way, wealthier nations have far greater emissions than their poorer counterparts. However, it is poorer nations who will be unable to pay the costly fees for the adaptation and [[Mitigation of climate change|mitigation]] needed to meet the challenges of climate change. Simply put, wealthy nations have the most to give and poorer nations have the most to lose. Climate engineering has the potential to address inequality by putting the burden on those who benefit from the emissions rather than sharing the burden with those who have little responsibility and who are doomed to suffer the most.<ref>{{Cite journal|last1=Harding|first1=Anthony R.|last2=Ricke|first2=Katharine|last3=Heyen|first3=Daniel|last4=MacMartin|first4=Douglas G.|last5=Moreno-Cruz|first5=Juan|date=2020-01-13|title=Climate econometric models indicate solar geoengineering would reduce inter-country income inequality|journal=Nature Communications|language=en|volume=11|issue=1|pages=227|doi=10.1038/s41467-019-13957-x|pmid=31932612|pmc=6957473|bibcode=2020NatCo..11..227H|issn=2041-1723|doi-access=free}}</ref>

=== Governance ===
Climate engineering opens up various political and economic issues. The governance issues characterizing carbon dioxide removal compared to solar geoengineering are largely distinct. As a result of these differing characteristics, the key governance problem for carbon dioxide removal (as with emissions reductions) is making sure actors do enough of it (the so-called "[[free rider problem]]"), whereas the key governance issue for solar geoengineering is making sure actors do not do it too early or too much (sometimes called the "free driver" problem).<ref>{{cite journal | doi=10.1111/sjoe.12120 | volume=117 | issue=4 | title=A Voting Architecture for the Governance of Free-Driver Externalities, with Application to Geoengineering | journal=The Scandinavian Journal of Economics | pages=1049–1068 | last1=Weitzman | first1=Martin L. | year=2015 | s2cid=2991157 | url=http://nrs.harvard.edu/urn-3:HUL.InstRepos:17368469 | access-date=2019-01-30 | archive-date=2020-06-09 | archive-url=https://web.archive.org/web/20200609205824/https://dash.harvard.edu/handle/1/17368469 | url-status=live }}</ref>

Domestic and international governance vary by the proposed climate engineering method. There is presently a lack of a universally agreed framework for the regulation of climate engineering activity or research. Scholars at the [[Oxford Martin School]] at [[Oxford University]] proposed a set of voluntary principles, which may guide climate engineering research and use. The short version of the 'Oxford Principles'<ref>{{Cite journal | last1 = Rayner | first1 = S. | last2 = Heyward | first2 = C. | last3 = Kruger | first3 = T. | last4 = Pidgeon | first4 = N. | last5 = Redgwell | first5 = C. | last6 = Savulescu | first6 = J. | title = The Oxford Principles | doi = 10.1007/s10584-012-0675-2 | journal = Climatic Change | year = 2013 | bibcode = 2013ClCh..121..499R | volume=121 | issue = 3 | pages=499–512| s2cid = 55553948 }}</ref> is:
* Principle 1: Geoengineering to be regulated as a [[Public good (economics)|public good]].
* Principle 2: Public participation in geoengineering decision-making
* Principle 3: Disclosure of geoengineering research and [[open access publication|open publication]] of results
* Principle 4: Independent assessment of impacts
* Principle 5: Governance before deployment
These principles have been endorsed by the [[House of Commons of the United Kingdom]] Science and Technology [[Select committee (United Kingdom)|Select Committee]] on "The Regulation of Geoengineering",<ref>{{Cite web|title = Oxford Geoengineering Programme // History of the Oxford Principles|url = http://www.geoengineering.ox.ac.uk/oxford-principles/history/|website = www.geoengineering.ox.ac.uk|access-date = 2016-02-03|author = Oxford Geoengineering Programme|archive-date = 2016-03-04|archive-url = https://web.archive.org/web/20160304040635/http://www.geoengineering.ox.ac.uk/oxford-principles/history/|url-status = live}}</ref> and have been referred to by authors discussing the issue of governance.<ref name="economist.com">{{Cite news |url=https://www.economist.com/science-and-technology/2010/03/31/we-all-want-to-change-the-world |title=We all want to change the world |date=March 31, 2010 |newspaper=The Economist |url-access=subscription |access-date=October 19, 2019 |archive-date=October 19, 2019 |archive-url=https://web.archive.org/web/20191019142946/https://www.economist.com/science-and-technology/2010/03/31/we-all-want-to-change-the-world |url-status=live }}</ref>

The [[Asilomar International Conference on Climate Intervention Technologies]] was convened to identify and develop risk reduction guidelines for climate intervention experimentation.<ref>{{cite web|title=Conference Home|url=http://climateresponsefund.org/index.php?option=com_content&view=article&id=137&Itemid=81|url-status=dead|archive-url=https://web.archive.org/web/20121016101517/http://climateresponsefund.org/index.php?option=com_content&view=article&id=137&Itemid=81|archive-date=2012-10-16|access-date=2012-09-06|publisher=Climateresponsefund.org}}</ref>

The Parties to the [[Convention on Biological Diversity]] have made three decisions on what they call "climate-related geo-engineering." That in 2010 called on countries to refrain from "climate-related geo-engineering activities that may affect biodiversity" until these are governed, they are scientifically justified, and associated risks have been considered.<ref>{{Cite web|last=Unit|first=Biosafety|title=COP Decision|url=https://www.cbd.int/decision/cop/?id=12299|access-date=2021-06-07|website=www.cbd.int|language=en|archive-date=2021-06-07|archive-url=https://web.archive.org/web/20210607152529/https://www.cbd.int/decision/cop/?id=12299|url-status=live}}</ref> Some critics of climate engineering call this a "de facto moratorium,"<ref>{{Cite journal|last1=Herkenrath|first1=Peter|last2=Harrison|first2=Jeremy|date=January 2011|title=The 10th meeting of the Conference of the Parties to the Convention on Biological Diversity—a breakthrough for biodiversity?|journal=Oryx|language=en|volume=45|issue=1|pages=1–2|doi=10.1017/S0030605310001663|issn=0030-6053|doi-access=free}}</ref> but the Secretariat of the Convention on Biological Diversity calls it a “non-binding normative framework.”<ref>{{Cite book|url=https://www.worldcat.org/oclc/889257942|title=Geoengineering in relation to the Convention on biological diversity : technical and regulatory matters.|date=2012|others=Phillip Williamson, Ralph Bodle, Secretariat of the Convention on Biological Diversity|isbn=978-9292254292|location=Montréal, Québec|oclc=889257942}}</ref> and many legal scholars reject this characterization.<ref>{{Cite journal|last=Scott|first=Karen|date=2013-01-01|title=International Law in the Anthropocene: Responding to the Geoengineering Challenge|url=https://repository.law.umich.edu/mjil/vol34/iss2/2|journal=Michigan Journal of International Law|volume=34|issue=2|pages=309–358|issn=1052-2867|access-date=2021-06-11|archive-date=2021-06-11|archive-url=https://web.archive.org/web/20210611114000/https://repository.law.umich.edu/mjil/vol34/iss2/2/|url-status=live}}</ref><ref>{{Cite journal|last1=Reynolds|first1=Jesse L.|last2=Parker|first2=Andy|last3=Irvine|first3=Peter|date=December 2016|title=Five solar geoengineering tropes that have outstayed their welcome: Five solar geoengineering tropes|url=http://doi.wiley.com/10.1002/2016EF000416|journal=Earth's Future|language=en|volume=4|issue=12|pages=562–568|doi=10.1002/2016EF000416}}</ref> The 2016 decision called for "more transdisciplinary research and sharing of knowledge among appropriate institutions is needed in order to better understand the impacts."<ref>{{Cite web|title=Convention on Biological Diversity|url=https://www.cbd.int/decisions/cop/13/14|access-date=2021-06-07|website=Convention on Biological Diversity|language=en|archive-date=2021-02-25|archive-url=https://web.archive.org/web/20210225075601/https://www.cbd.int/decisions/cop/13/14|url-status=live}}</ref>

==Public perception==
A large 2018 study investigated public perceptions of six climate engineering methods, with an online survey in the United States, United Kingdom, Australia, and New Zealand.<ref name=":1">{{Cite journal|last1=Carlisle|first1=Daniel P.|last2=Feetham|first2=Pamela M.|last3=Wright|first3=Malcolm J.|last4=Teagle|first4=Damon A. H.|date=2020-04-12|title=The public remain uninformed and wary of climate engineering|journal=Climatic Change|volume=160|issue=2|pages=303–322|language=en|doi=10.1007/s10584-020-02706-5|bibcode=2020ClCh..160..303C|s2cid=215731777|issn=1573-1480|url=https://eprints.soton.ac.uk/440717/1/Thepublic_remain_uninformed.pdf|access-date=2021-05-18|archive-date=2021-06-14|archive-url=https://web.archive.org/web/20210614062101/https://eprints.soton.ac.uk/440717/1/Thepublic_remain_uninformed.pdf|url-status=live}}</ref> The findings were also compared against a similar 2012 survey in Australia and New Zealand.<ref name=":2">{{Cite journal|last1=Wright|first1=Malcolm J.|last2=Teagle|first2=Damon A. H.|last3=Feetham|first3=Pamela M.|date=February 2014|title=A quantitative evaluation of the public response to climate engineering|url=https://www.nature.com/articles/nclimate2087|journal=Nature Climate Change|language=en|volume=4|issue=2|pages=106–110|doi=10.1038/nclimate2087|bibcode=2014NatCC...4..106W|issn=1758-6798|access-date=2020-05-22|archive-date=2020-07-28|archive-url=https://web.archive.org/web/20200728153000/https://www.nature.com/articles/nclimate2087|url-status=live}}</ref> Public awareness of climate engineering was low with less than a fifth of respondents reporting prior knowledge. Perceptions of the six climate engineering methods were largely negative and frequently associated with attributes like 'risky', 'artificial' and 'unknown effects'. Carbon dioxide removal methods were preferred over solar geoengineering. Public perceptions were remarkably stable with only minor differences between the different countries in the 2018 and 2012 surveys.<ref name=":1" /><ref name=":2" />

In a 2017 focus group study conducted by the [[Cooperative Institute for Research in Environmental Sciences]] (CIRES) in the United States, Japan, New Zealand, and Sweden, participants were asked about carbon sequestration options, reflection proposals such as with space mirrors, or brightening of clouds, and their majority responses could be summed up as follows:

* What happens if the technologies backfire with unintended consequences?
* Are these solutions treating the symptoms of climate change rather than the cause?
* Shouldn't we just change our lifestyle and consumption patterns to fight climate change, making climate engineering a last resort?
* Isn't there a greater need to address political solutions to reduce our emissions?

Moderators then floated the idea of a future "climate emergency" such as rapid environmental change. The participants felt that mitigation and adaptation to climate change were strongly preferred options in such a situation, and climate engineering was seen as a last resort.<ref>{{cite web|url=http://cires.colorado.edu/news/study-illuminates-public-perceptions-climate-engineering|date=October 9, 2017|title=Study Illuminates Public Perceptions of Climate Engineering|work=CIRES|access-date=August 20, 2018|archive-date=August 21, 2018|archive-url=https://web.archive.org/web/20180821031843/https://cires.colorado.edu/news/study-illuminates-public-perceptions-climate-engineering|url-status=live}}</ref>
Some extremists have proposed that there are secret government actions implementing geoengineering on a large scale, affecting weather to produce winter, or cooling, or large fires, or other detrimental effects. There is no evidence to substantiate these unorthodox claims.

==Evaluations of climate engineering==
Most of what is known about the suggested techniques are based on laboratory experiments, observations of natural phenomena, and [[computer modeling]] techniques. Some proposed climate engineering methods employ methods that have analogs in natural phenomena such as [[stratospheric sulfur aerosols]] and [[cloud condensation nuclei]]. As such, studies about the efficacy of these methods can draw on information already available from other research, such as that following the [[1991 eruption of Mount Pinatubo]]. However, comparative evaluation of the relative merits of each technology is complicated, especially given modeling uncertainties and the early stage of engineering development of many proposed climate engineering methods.<ref>{{Cite web|title=Geo-Engineering Inquiry|date=November 17, 2008|url=http://www.imeche.org/media/Public+Affairs/geoenginq.htm|website=Institution of Mechanical Engineers|url-status=dead|archive-url=https://web.archive.org/web/20081220180833/http://www.imeche.org/media/Public+Affairs/geoenginq.htm|archive-date=2008-12-20}}</ref>

Several organizations have investigated climate engineering with a view to evaluating its potential, including the [[US Congress]],<ref name="Bullis">{{cite web|last=Bullis|first=Kevin|title=U.S. Congress Considers Geoengineering|url=http://www.technologyreview.com/view/416187/us-congress-considers-geoengineering/|access-date=26 December 2012|work=MIT Technology Review|archive-date=26 January 2013|archive-url=https://web.archive.org/web/20130126213315/http://www.technologyreview.com/view/416187/us-congress-considers-geoengineering/|url-status=live}}</ref> the US National Academy of Sciences, Engineering, and Medicine,<ref>{{Cite web|title=Climate Intervention Reports » Climate Change at the National Academies of Sciences, Engineering, and Medicine|url=https://nas-sites.org/americasclimatechoices/other-reports-on-climate-change/2015-2/climate-intervention-reports/|access-date=2015-11-02|website=nas-sites.org|archive-date=2016-07-29|archive-url=https://web.archive.org/web/20160729015758/http://nas-sites.org/americasclimatechoices/other-reports-on-climate-change/2015-2/climate-intervention-reports/|url-status=live}}</ref> the [[Royal Society]],<ref>{{cite press release|title=Stop emitting CO2 or geoengineering could be our only hope|url=http://royalsociety.org/Stop-emitting-CO2-or-geoengineering-could-be-our-only-hope/|date=28 August 2009|publisher=The Royal Society|access-date=14 June 2011|archive-date=24 June 2011|archive-url=https://web.archive.org/web/20110624054716/http://royalsociety.org/Stop-emitting-CO2-or-geoengineering-could-be-our-only-hope/|url-status=live}}</ref> the [[UK Parliament]],<ref>{{cite web|date=March 2009|title=Geo-engineering research|url=http://www.parliament.uk/documents/upload/postpn327.pdf|url-status=dead|archive-url=https://web.archive.org/web/20090618133101/http://www.parliament.uk/documents/upload/postpn327.pdf|archive-date=2009-06-18|access-date=2009-05-23|work=Postnote|publisher=Parliamentary Office of Science and Technology}}</ref> the [[Institution of Mechanical Engineers]],<ref name="imeche09"/> and the [[Intergovernmental Panel on Climate Change]]. The IMechE report examined a small subset of proposed methods (air capture, urban albedo and algal-based {{co2}} capture techniques), and its main conclusions were that climate engineering should be researched and trialed at the small scale alongside a wider decarbonization of the economy.<ref name="imeche09"/>

The Royal Society review examined a wide range of proposed climate engineering methods and evaluated them in terms of effectiveness, affordability, timeliness, and safety (assigning [[qualitative data|qualitative]] estimates in each assessment). The key recommendations of the reports were that "Parties to the [[UNFCCC]] should make increased efforts towards mitigating and adapting to climate change, and in particular to agreeing to global emissions reductions", and that "[nothing] now known about geoengineering options gives any reason to diminish these efforts".<ref name="Royal Society Policy Document"/> Nonetheless, the report also recommended that "research and development of climate engineering options should be undertaken to investigate whether low-risk methods can be made available if it becomes necessary to reduce the rate of warming this century".<ref name="Royal Society Policy Document"/>

In a 2009 review study, Lenton and Vaughan evaluated a range of proposed climate engineering techniques.<ref name="lenton09"/> In order to permit a comparison of disparate techniques, they used a common evaluation for each technique based on its effect on net radiative forcing. As such, the review examined the scientific plausibility of proposed methods rather than the practical considerations such as engineering feasibility or economic cost. Lenton and Vaughan found that "[air] capture and storage shows the greatest potential, combined with afforestation, reforestation and bio-char production", and noted that "other suggestions that have received considerable media attention, in particular, "ocean pipes" appear to be ineffective".<ref name="lenton09"/> They concluded that "[climate] geoengineering is best considered as a potential complement to the mitigation of {{co2}} emissions, rather than as an alternative to it".<ref name="lenton09"/>

In October 2011, a [[Bipartisan Policy Center]] panel issued a report urging immediate research and testing in case "the climate system reaches a 'tipping point' and swift remedial action is required."<ref>{{Cite news|last=Dean|first=Cornelia|date=2011-10-04|title=Group Urges Research Into Aggressive Efforts to Fight Climate Change|language=en-US|work=The New York Times|url=https://www.nytimes.com/2011/10/04/science/earth/04climate.html|access-date=2021-08-14|issn=0362-4331|archive-date=2021-06-14|archive-url=https://web.archive.org/web/20210614062059/https://www.nytimes.com/2011/10/04/science/earth/04climate.html|url-status=live}}</ref>

The US National Academy of Sciences, Engineering, and Medicine conducted a 21-month project to study the potential impacts, benefits, and costs of climate engineering. The differences between these two classes of climate engineering "led the committee to evaluate the two types of approaches separately in companion reports, a distinction it hopes will carry over to future scientific and policy discussions."<ref name="www8.nationalacademies.org">{{Cite press release|title = Climate Intervention Is Not a Replacement for Reducing Carbon Emissions; Proposed Intervention Techniques Not Ready for Wide-Scale Deployment|url = http://www8.nationalacademies.org/onpinews/newsitem.aspx?RecordID=02102015|website = NEWS from the national academies|date = Feb 10, 2015|access-date = 2015-11-24|archive-date = 2015-11-17|archive-url = https://web.archive.org/web/20151117032144/http://www8.nationalacademies.org/onpinews/newsitem.aspx?RecordID=02102015|url-status = live}}</ref><ref name="Climate Intervention" /><ref>{{Cite book|last=Council|first=National Research|url=https://www.nap.edu/catalog/18805/climate-intervention-carbon-dioxide-removal-and-reliable-sequestration|title=Climate Intervention: Carbon Dioxide Removal and Reliable Sequestration|date=2015|isbn=978-0-309-30529-7|language=en|doi=10.17226/18805|access-date=2018-08-20|archive-date=2018-08-21|archive-url=https://web.archive.org/web/20180821031740/https://www.nap.edu/catalog/18805/climate-intervention-carbon-dioxide-removal-and-reliable-sequestration|url-status=live}}</ref> The resulting study titled ''Climate Intervention'' was released in February 2015 and consists of two volumes: ''Reflecting Sunlight to Cool Earth''<ref name="Council">{{Cite book|last=Council|first=National Research|url=https://www.nap.edu/catalog/18988/climate-intervention-reflecting-sunlight-to-cool-earth|title=Climate Intervention: Reflecting Sunlight to Cool Earth|date=2015-02-10|isbn=978-0-309-31482-4|language=en|access-date=2018-08-20|archive-date=2019-12-14|archive-url=https://web.archive.org/web/20191214192318/http://www.nap.edu/catalog.php?record_id=18988|url-status=live}}</ref> and ''Carbon Dioxide Removal and Reliable Sequestration''.<ref>{{Cite book|last=Council|first=National Research|url=https://www.nap.edu/catalog/18805/climate-intervention-carbon-dioxide-removal-and-reliable-sequestration|title=Climate Intervention: Carbon Dioxide Removal and Reliable Sequestration|date=2015-02-10|isbn=978-0-309-30529-7|language=en|access-date=2018-08-20|archive-date=2018-08-21|archive-url=https://web.archive.org/web/20180821031740/https://www.nap.edu/catalog/18805/climate-intervention-carbon-dioxide-removal-and-reliable-sequestration|url-status=live}}</ref> According to their brief about the study:<ref name="nas-sites.org">{{Cite web|title = Climate Intervention Reports » Climate Change at the National Academies of Sciences, Engineering, and Medicine|url = https://nas-sites.org/americasclimatechoices/other-reports-on-climate-change/2015-2/climate-intervention-reports/|website = nas-sites.org|access-date = 2015-09-02|archive-date = 2016-07-29|archive-url = https://web.archive.org/web/20160729015758/http://nas-sites.org/americasclimatechoices/other-reports-on-climate-change/2015-2/climate-intervention-reports/|url-status = live}}</ref>{{,}}<ref name="Council"/><blockquote>Climate intervention is no substitute for reductions in carbon dioxide emissions and adaptation efforts aimed at reducing the negative consequences of climate change. However, as our planet enters a period of changing climate never before experienced in recorded human history, interest is growing in the potential for deliberate intervention in the climate system to counter climate change... Carbon dioxide removal strategies address a key driver of climate change, but research is needed to fully assess if any of these technologies could be appropriate for large-scale deployment. Albedo modification strategies could rapidly cool the planet's surface but pose environmental and other risks that are not well understood and therefore should not be deployed at climate-altering scales; more research is needed to determine if albedo modification approaches could be viable in the future.</blockquote>

==See also==
{{Portal|Environment|Weather|Global warming}}
{{div col|colwidth=22em}}
* [[Arctic geoengineering]]
* [[Carbon negative fuel]]
* Convention on Biological Diversity
* [[Earth systems engineering and management]]
* ''[[Five Ways to Save the World]]''
* [[Haida Gwaii#2012 controversy around depositing iron in the ocean|Haida Gwaii geoengineering controversy]]
* [[Land surface effects on climate]]
* [[List of geoengineering topics]]
* [[Moving the Earth]]
* [[One Earth Climate Model]]
* [[Planetary engineering]]
* [[Project Stormfury]]
* [[Technological fix]]
* [[Terraforming]]
* [[Weather modification]]
* [[Weather modification in North America]]
{{div col end}}

==References==
{{Reflist}}

==External links==
* {{YouTube|id=1hhzrormtP4|title=Geoengineering May Be the Answer to Climate Change}} published December 14, 2019 [[Vice News]]

==Further reading==
* {{cite book|last=Kintisch|first=Eli|title=Hack the Planet: Science's Best Hope, or Worst Nightmare, for Averting Climate Catastrophe|url={{google books |plainurl=y |id=if5xZw7MiwAC}}|publisher=Wiley|year=2010|isbn=978-0-470-52426-8}}
* {{cite book|last=Goodell|first=Jeff|title=How to Cool the Planet: Geoengineering and the Audacious Quest to Fix Earth's Climate|url={{google books |plainurl=y |id=5hAnBB-wmH4C}}|publisher=Houghton Mifflin Harcourt|year=2010|isbn=978-0-618-99061-0}}
* {{cite book|last=Hamilton|first=Clive|title=Earthmasters: Playing God with the Climate|url={{google books |plainurl=y |id=6RoK8Xh_mHAC}}|publisher=Allen & Unwin|year=2013|isbn=978-1743312933}}
* {{cite book|last=Keith|first=David|title=A Case for Climate Engineering|url={{google books |plainurl=y |id=JXf6AAAAQBAJA}}|publisher=MIT Press|year=2013|isbn=9780262019828}}
* {{cite book|last=Morton|first=Oliver|title=The Planet Remade: How Geoengineering Could Change the World|url={{google books |plainurl=y |id=428uCgAAQBAJ}}|publisher=Princeton|year=2015|isbn=9780691175904}}
* {{cite report | author=Royal Society working group|publisher=The Royal Society |url=http://royalsociety.org/uploadedFiles/Royal_Society_Content/policy/publications/2009/8693.pdf |title=Geoengineering the Climate: Science, Governance and Uncertainty | date=2009 |location=London |isbn=978-0-85403-773-5 |id=RS1636 |access-date=2011-12-01}}
* {{Cite web|title=Geoengineering |publisher=[[Heinrich Böll Foundation|Heinrich Böll Stiftung]]|url=https://www.boell.de/en/geoengineering|access-date=2021-08-14|website=Heinrich-Böll-Stiftung|language=en}}
* {{cite web |url= https://www.europarl.europa.eu/RegData/etudes/ATAG/2021/656339/EPRS_ATA(2021)656339_EN.pdf |title= What if we could engineer the planet to help fight climate change? |publisher= [[European Parliamentary Research Service]] |work= Scientific Foresight Unit |date= February 2021 |author= Lieve Van Woensel with Marcos Fernández Álvarez}}
* {{Cite journal|last1=Zarnetske|first1=Phoebe L.|author-link1=Phoebe L. Zarnetske|last2=Gurevitch|first2=Jessica|author-link2=Jessica Gurevitch|last3=Franklin|first3=Janet|last4=Groffman|first4=Peter M.|last5=Harrison|first5=Cheryl S.|last6=Hellmann|first6=Jessica J.|last7=Hoffman|first7=Forrest M.|last8=Kothari|first8=Shan|last9=Robock|first9=Alan|last10=Tilmes|first10=Simone|last11=Visioni|first11=Daniele|date=2021-04-13|title=Potential ecological impacts of climate intervention by reflecting sunlight to cool Earth|journal=Proceedings of the National Academy of Sciences|language=en|volume=118|issue=15|pages=e1921854118|doi=10.1073/pnas.1921854118|pmid=33876741|pmc=8053992|bibcode=2021PNAS..11821854Z|issn=0027-8424|doi-access=free}}

{{Global warming}}
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[[Category:Climate engineering| ]]
[[Category:Climate change policy]]
[[Category:Emissions reduction]]
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[[Category:Planetary engineering]]
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