View source for Geoengineering

{{Short description|Deliberate and large-scale intervention in Earth's climate system}}
{{Citation style|date=November 2025}}
{{Hatnote group|{{Distinguish|text=[[Weather modification]]}}{{Other uses}}}}
{{Use dmy dates|date=October 2025}}
'''Geoengineering''' (also known as '''climate engineering''' or '''climate intervention''') is the deliberate large-scale interventions in the Earth’s climate system intended to counteract human-caused [[climate change]].<ref name=":0">{{Cite web |last=World Climate Research Programme |title=Research on Climate Intervention |url=https://www.wcrp-climate.org/ci-overview |website=www.wcrp-climate.org}}</ref> The term commonly encompasses two broad categories: large-scale [[carbon dioxide removal]] (CDR) and [[solar radiation modification]] (SRM). CDR involves techniques to remove [[carbon dioxide]] from the atmosphere and is generally considered a form of  [[climate change mitigation]]. SRM aims to reduce global warming by reflecting a small portion of  [[Solar irradiance|sunlight (solar radiation)]] away from Earth and back into space. Although historically grouped together, these approaches differ substantially in mechanisms, timelines, and risk profiles, and are now typically discussed separately.<ref name="AR6 WGIII Ch 1">IPCC (2022) [https://www.ipcc.ch/report/ar6/wg3/downloads/report/IPCC_AR6_WGIII_Chapter01.pdf Chapter 1: Introduction and Framing] in [https://www.ipcc.ch/report/ar6/wg3/ Climate Change 2022: Mitigation of Climate Change. Contribution of Working Group III to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change], Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA</ref>{{rp|168}}<ref name="IPCC AR6 WGI Glossary">IPCC, 2021: [https://www.ipcc.ch/report/ar6/wg1/downloads/report/IPCC_AR6_WGI_AnnexVII.pdf Annex VII: Glossary] [Matthews, J.B.R., V. Möller, R. van Diemen, J.S. Fuglestvedt, V. Masson-Delmotte, C.&nbsp; Méndez, S. Semenov, A. Reisinger (eds.)]. In [https://www.ipcc.ch/report/ar6/wg1/ Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change] [Masson-Delmotte, V., P. Zhai, A. Pirani, S.L. Connors, C. Péan, S. Berger, N. Caud, Y. Chen, L. Goldfarb, M.I. Gomis, M. Huang, K. Leitzell, E. Lonnoy, J.B.R. Matthews, T.K. Maycock, T. Waterfield, O. Yelekçi, R. Yu, and B. Zhou (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, pp. 2215–2256, {{doi|10.1017/9781009157896.022}}.</ref> Some other large-scale engineering proposals—such as interventions to slow the melting of polar and alpine ice—are also sometimes classified as forms of geoengineering.

Some types of geoengineering present political, social and ethical issues. One common objection is that focusing on these technologies could undermine efforts to reduce greenhouse gas emissions. Effective governance and international oversight are widely regarded as essential.

Major scientific organizations have examined the potential, risks, and governance needs of geoengineering, including the [[National Academies of Sciences, Engineering, and Medicine|US National Academies of Sciences, Engineering, and Medicine]],<ref>{{Cite book |url=http://www.nap.edu/catalog/1605 |title=Policy Implications of Greenhouse Warming: Mitigation, Adaptation, and the Science Base |date=1 January 1992 |publisher=National Academies Press |isbn=978-0-309-04386-1 |location=Washington, D.C. |bibcode=1992nap..book.1605I |doi=10.17226/1605}}</ref><ref>{{Cite book |url=http://www.nap.edu/catalog/18805 |title=Climate Intervention: Carbon Dioxide Removal and Reliable Sequestration |date=17 June 2015 |publisher=National Academies Press |isbn=978-0-309-30529-7 |location=Washington, D.C. |bibcode=2015nap..book18805N |doi=10.17226/18805}}</ref><ref>{{Cite book |url=http://www.nap.edu/catalog/18988 |title=Climate Intervention: Reflecting Sunlight to Cool Earth |date=23 June 2015 |publisher=National Academies Press |isbn=978-0-309-31482-4 |location=Washington, D.C. |bibcode=2015nap..book18988N |doi=10.17226/18988}}</ref> the [[Royal Society]],<ref name="RoyalSociety2009">{{Cite book |title=Geoengineering the climate: Science, governance and uncertainty |date=2009 |isbn=978-0-85403-773-5 |editor-last=Royal Society of London |location=London}}</ref> the UN Educational, Scientific and Cultural Organization ([[UNESCO]]),<ref name=":1">{{Cite web |last=UNESCO World Commission on the Ethics of Scientific Knowledge and Technology |date=2023 |title=Report of the World Commission on the Ethics of Scientific Knowledge and Technology (COMEST) on the ethics of climate engineering |url=https://unesdoc.unesco.org/ark:/48223/pf0000386677 |access-date=9 March 2024}}</ref> and the [[World Climate Research Programme]].<ref name=":0" />

== Methods ==

=== Carbon dioxide removal ===
{{excerpt|carbon dioxide removal|paragraphs=1-2}}

=== Solar radiation modification ===
[[File:SPICE_SRM_overview.jpg|alt=refer to caption and image description|thumb|Proposed solar radiation modification using a tethered balloon to inject sulfate aerosols into the stratosphere]]
{{excerpt|Solar geoengineering|paragraphs=1-2|file=no}}

=== Glacial geoengineering ===
{{Excerpt|Glacial geoengineering}}

== Governance ==
Most governance issues relating to geoengineering are specific to the category or the specific method. Nevertheless, a couple of international governance instruments have addressed geoengineering collectively.

The Conference of Parties to the [[Convention on Biological Diversity]] have made several decisions regarding "climate related geoengineering." That of 2010 established "a comprehensive non-binding normative framework"<ref>{{Cite book |title=Geoengineering in relation to the Convention on Biological Diversity |date=2012 |publisher=Secretariat of the Convention on Biological Diversity |isbn=978-92-9225-429-2 |series=CBD technical series |location=Montreal}}</ref>{{Rp|page=106}} for "climate-related geoengineering activities that may affect biodiversity," requesting that such activities be justified by the need to gather specific scientific data, undergo prior environmental assessment, be subject to effective regulatory oversight.<ref name="NAP2021">{{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=25 March 2021 |isbn=978-0-309-67605-2 |language=en |bibcode=2021nap..book25762N |doi=10.17226/25762 |access-date=17 April 2021 |archive-url=https://web.archive.org/web/20210417055338/https://www.nap.edu/catalog/25762/reflecting-sunlight-recommendations-for-solar-geoengineering-research-and-research-governance |archive-date=17 April 2021 |url-status=live}}</ref>{{Rp|pages=96–97}}<ref name=":12">{{Cite report |url=https://zenodo.org/doi/10.5281/zenodo.14283096 |title=Solar radiation modification: evidence review report |author1=Scientific Advice Mechanism to the European Commission |date=9 December 2024 |publisher=SAPEA |doi=10.5281/zenodo.14283096 |language=en}}</ref>{{Rp|pages=161–162}} The Parties' 2016 decision called for "more transdisciplinary research and sharing of knowledge... in order to better understand the impacts of climate-related geoengineering."<ref name=":12" />{{Rp|pages=|page=161–162}}<ref>{{Cite book |last=Convention on Biological Diversity |first=Conference of the Parties to the |url=https://www.cbd.int/doc/decisions/cop-13/cop-13-dec-14-en.pdf |title=Decision Adopted by the Conference of the Parties to the Convention on Biological Diversity, XIII/14. Climate-related Geoengineering |date=8 December 2016}}</ref>

The parties to the [[London Convention on the Prevention of Marine Pollution by Dumping of Wastes and Other Matter]] and its associated London Protocol have addressed "marine geoengineering." In 2013, the parties to the London Protocol adopted an amendment to establish a legally binding framework for regulating marine geoengineering, initially limited to ocean fertilization and requiring assessment and permitting before any activity proceeds. This amendment has not yet entered into force due to insufficient ratifications. In 2022, the parties to both agreements acknowledged growing interest in marine geoengineering, identified four techniques for priority review, and encouraged careful assessment of proposed projects under existing guidelines while considering options for further regulation. In 2023, they cautioned that these techniques could pose serious environmental risks, highlighted scientific uncertainty about their effects, urged strict application of assessment frameworks, and called for broader international cooperation.<ref>{{Cite web |last=International Maritime Organization |title=Marine geoengineering |url=https://www.imo.org/en/OurWork/Environment/Pages/geoengineering-Default.aspx}}</ref> Their work is supported by the Joint Group of Experts on the Scientific Aspects of Marine Environmental Protection of the [[International Maritime Organization]].{{Portal|Environment|Weather|Global warming}}

==References==
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{{Climate change}}
{{Human impact on the environment}}
{{Engineering fields}}
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[[Category:Geoengineering| ]]
[[Category:Climate change|Engineering]]
[[Category:Climate change policy|Engineering]]
[[Category:Emissions reduction]]
[[Category:Engineering disciplines]]
[[Category:Planetary engineering]]