View source for Environmental mitigation

{{Short description|Measures to avoid, minimise, or compensate for adverse impacts on the environment}}
'''Environmental mitigation''' refers to the process by which measures to avoid, minimise, or compensate for adverse impacts on the environment are applied.<ref name=":1">{{Cite web |title=Mitigation {{!}} Caltrans |url=https://dot.ca.gov/programs/environmental-analysis/biology/mitigation |access-date=2024-08-01 |website=dot.ca.gov |language=en}}</ref> In the context of planning processes like [[Environmental impact assessment|Environmental Impact Assessments]], this process is often guided by applying conceptual frameworks like the "mitigation hierarchy" or "mitigation sequence".<ref>{{Cite web |title=Mitigation hierarchy - The Biodiversity Consultancy |url=https://www.thebiodiversityconsultancy.com/our-work/our-expertise/strategy/mitigation-hierarchy/ |access-date=2024-08-01 |website=www.thebiodiversityconsultancy.com}}</ref> This generally includes the steps avoid, reduce, restore, and offset.<ref name=":7">{{Cite web |title=Mitigation Hierarchy |url=https://nationalzoo.si.edu/ccs/mitigation-hierarchy |access-date=2024-08-02 |website=Smithsonian's National Zoo and Conservation Biology Institute |language=en}}</ref> In some countries, environmental mitigation measures, including [[biodiversity offsetting]], may be required by law.<ref>{{Cite web |title=Mitigation and onsite works {{!}} Ecology by Design |url=https://www.ecologybydesign.co.uk/ecology-consultancy-services/mitigation-and-onsite-works |access-date=2024-08-01 |website={{!}} Ecology by Design |language=en-GB}}</ref>

In practice, environmental mitigation measures might be implemented by establishing new habitat, restoring [[Land degradation|degraded habitat]], and preserving or enhancing existing habitats to offset impacts that cannot be avoided or reduced.<ref>{{Cite web |last=US EPA |first=OW |date=2015-06-22 |title=Background about Compensatory Mitigation Requirements under CWA Section 404 |url=https://www.epa.gov/cwa-404/background-about-compensatory-mitigation-requirements-under-cwa-section-404 |access-date=2024-08-02 |website=www.epa.gov |language=en}}</ref> It is also often applied with certain objectives for biodiversity levels or specific ecosystems in mind, such as [[No net loss environmental policy|"no net loss"]] or "net gain".<ref>{{Cite web |title=Biodiversity offsets |url=https://www.iucn.org/resources/issues-brief/biodiversity-offsets |access-date=2024-08-02 |website=www.iucn.org |language=en}}</ref>

== Terminology ==
Environmental mitigation can be defined in various ways depending on the institutions and countries where the term is applied, or on the framework that is used to guide mitigation. For example, it may be defined as the process by which measures to avoid, minimise, or compensate for adverse impacts on the environment are applied.<ref name=":1" /> 

According to the Business and Biodiversity Offsets Programme, mitigation is defined as "measures to reduce impacts to the point where they have no adverse effects", including avoidance, minimisation, restoration, offsetting and compensation.<ref name=":8">{{Cite web |date=2018-11-02 |title=Business and Biodiversity Offsets Programme Glossary 2018 |url=https://www.forest-trends.org/bbop_pubs/glossary_2018/ |access-date=2024-08-08 |website=Forest Trends |language=en-US}}</ref>

The term mitigation is used synonymously with [[biodiversity offsetting]] in some countries. For example, in the US, what is referred to as "biodiversity offsetting" in Australia, the UK, and South Africa comes under the term compensatory mitigation.<ref>{{Cite journal |last1=Bull |first1=Joseph W. |last2=Gordon |first2=Ascelin |last3=Watson |first3=James E. M. |last4=Maron |first4=Martine |date=2016 |editor-last=Carvalho |editor-first=Silvia |title=Seeking convergence on the key concepts in 'no net loss' policy |url=https://besjournals.onlinelibrary.wiley.com/doi/10.1111/1365-2664.12726 |journal=Journal of Applied Ecology |language=en |volume=53 |issue=6 |pages=1686–1693 |doi=10.1111/1365-2664.12726 |bibcode=2016JApEc..53.1686B |issn=0021-8901}}</ref> Biodiversity offsets are classified as a type of mitigation measure and are defined in the [[United Nations]]' biodiversity glossary as "measurable conservation outcomes resulting from actions designed to compensate for significant residual adverse biodiversity impacts arising from project development after appropriate prevention and mitigation measures have been taken."<ref>{{Cite web |title=Biodiversity offsets definition{{!}} Biodiversity A-Z |url=https://biodiversitya-z.org/content/biodiversity-offsets |access-date=2024-08-01 |website=biodiversitya-z.org}}</ref>

[[Climate change mitigation]] focuses specifically on actions to limit climate change by reducing net greenhouse gas emissions, while the scope of environmental mitigation is broader. 

== Background ==
[[File:1970- Decline in species populations - Living Planet Index.svg|alt=Chart showing the Living Planet Index, global extent, from 1970, with 95% confidence interval, showing decline in species population|thumb|Living Planet Index, global extent, from 1970, with 95% confidence interval, showing decline in species population.]]
[[Biodiversity loss]] is occurring on a global scale and humans are driving this through changes in land use, exploitation of organisms, [[climate change]], [[pollution]], and [[invasive species]].<ref>{{Cite report |url=https://zenodo.org/records/3553579 |title=Summary for policymakers of the global assessment report on biodiversity and ecosystem services |last=IPBES |date=2019-11-25 |doi=10.5281/zenodo.3553579}}</ref> According to WWF's Living Planet Report, these drivers are underpinned by rapid [[economic growth]] and [[Population growth|human population growth]] over the past 50 years.<ref>{{Cite journal |last1=Ledger |first1=Sophie E. H. |last2=Loh |first2=Jonathan |last3=Almond |first3=Rosamunde |last4=Böhm |first4=Monika |last5=Clements |first5=Christopher F. |last6=Currie |first6=Jessica |last7=Deinet |first7=Stefanie |last8=Galewski |first8=Thomas |last9=Grooten |first9=Monique |last10=Jenkins |first10=Martin |last11=Marconi |first11=Valentina |last12=Painter |first12=Brett |last13=Scott-Gatty |first13=Kate |last14=Young |first14=Lucy |last15=Hoffmann |first15=Michael |date=2023-06-01 |title=Past, present, and future of the Living Planet Index |url=http://dx.doi.org/10.1038/s44185-023-00017-3 |journal=npj Biodiversity |volume=2 |issue=1 |doi=10.1038/s44185-023-00017-3 |issn=2731-4243}}</ref>

The need to address biodiversity loss and to reconcile this with economic development so that sustainability and conservation goals can be met has motivated the development of environmental mitigation measures, like [[biodiversity offsetting]] and [[mitigation banking]].<ref name=":2">Carroll, N., Fox, J. (Jessica A. ), & Bayon, R. (2008). ''Conservation and biodiversity banking : a guide to setting up and running biodiversity credit trading systems''. Earthscan.</ref> A growing awareness of this has led to the expansion of legal requirements for environmental mitigation globally - 191 of the [[Member states of the United Nations|United Nations member states]] have Environment Impact Assessment legislation and more than 108 countries now have policies for biodiversity offsetting, a form of environmental mitigation.<ref>{{Cite journal |last=Morgan |first=Richard K. |date=2012 |title=Environmental impact assessment: the state of the art |url=http://www.tandfonline.com/doi/abs/10.1080/14615517.2012.661557 |journal=Impact Assessment and Project Appraisal |language=en |volume=30 |issue=1 |pages=5–14 |doi=10.1080/14615517.2012.661557 |bibcode=2012IAPA...30....5M |issn=1461-5517|url-access=subscription }}</ref><ref name=":9">{{Cite journal |last1=Bull |first1=Joseph William |last2=Strange |first2=Niels |date=2018 |title=The global extent of biodiversity offset implementation under no net loss policies |url=https://www.nature.com/articles/s41893-018-0176-z |journal=Nature Sustainability |language=en |volume=1 |issue=12 |pages=790–798 |doi=10.1038/s41893-018-0176-z |bibcode=2018NatSu...1..790B |issn=2398-9629}}</ref>

== Aims ==
{{Further information|No net loss environmental policy}}
Environmental mitigation is often applied with the aim of achieving a specific goal such as "[[No net loss environmental policy|no net loss]]" (NNL) or a "net positive impact" (NPI) by using frameworks like the mitigation hierarchy.<ref>{{Cite web |date=2018-09-07 |title=‘No Net Loss’ and ‘Net Gain’ of biodiversity |url=https://www.forest-trends.org/bbop/bbop-key-concepts/no-net-loss-and-net-gain-of-biodiversity/ |access-date=2024-08-08 |website=Forest Trends |language=en-US}}</ref> Depending on requirement, aims might be applied on the level of a single development site or on the level of landscapes, regions, and whole countries. 

* '''No net loss -''' an environmental policy that aims to neutralise the loss of biodiversity, relative to an appropriately determined reference scenario.<ref>{{Cite web |title=No-net loss definition{{!}} Biodiversity A-Z |url=https://www.biodiversitya-z.org/content/no-net-loss |access-date=2024-08-08 |website=www.biodiversitya-z.org}}</ref>

* '''Net positive impact''' - a goal for the outcomes of a development project where the aim is for the negative environmental impacts of the project to be outweighed by the positive impacts of environmental mitigation measures;<ref>{{Cite web |title=Net positive impact (NPI) definition{{!}} Biodiversity A-Z |url=https://www.biodiversitya-z.org/content/net-positive-impact-npi |access-date=2024-08-08 |website=www.biodiversitya-z.org}}</ref> the goal is for the level of biodiversity to be greater than it was before the project.

Working towards these aims using the mitigation hierarchy (see [[Environmental mitigation#Mitigation hierarchy|§ Mitigation hierarchy]] below) as a tool to guide environmental mitigation measures like [[biodiversity offsetting]] has been put forward as a way of contributing to broader societal goals for [[biodiversity]] and [[Conservation biology|conservation]], such as the [[Kunming-Montreal Global Biodiversity Framework|Global Biodiversity Framework]] or [[Nature-positive|nature positive]].<ref>{{Cite web |last=Unit |first=Biosafety |title=Target 19 |url=https://www.cbd.int/gbf/targets/19 |access-date=2024-08-08 |website=www.cbd.int |language=en}}</ref><ref>{{Cite journal |last=Maron |first=Martine |last2=Quétier |first2=Fabien |last3=Sarmiento |first3=Mariana |last4=ten Kate |first4=Kerry |last5=Evans |first5=Megan C. |last6=Bull |first6=Joseph W. |last7=Jones |first7=Julia P. G. |last8=zu Ermgassen |first8=Sophus O. S. E. |last9=Milner-Gulland |first9=E. J. |last10=Brownlie |first10=Susie |last11=Treweek |first11=Jo |last12=von Hase |first12=Amrei |date=2024 |title=‘Nature positive’ must incorporate, not undermine, the mitigation hierarchy |url=https://www.nature.com/articles/s41559-023-02199-2 |journal=Nature Ecology & Evolution |language=en |volume=8 |issue=1 |pages=14–17 |doi=10.1038/s41559-023-02199-2 |issn=2397-334X}}</ref> This is debated and the role of aims like NNL and tools like biodiversity offsetting to achieve or undermine conservation goals is disputed.<ref name=":6" />

== Mitigation hierarchy ==
The mitigation hierarchy is a tool that is commonly used to guide the application of environmental mitigation measures. It aims to manage risks by applying a sequence of steps.<ref>BBOP & UNEP (2010) Mitigation Hierarchy. Business and Biodiversity Offsets Programme & United Nations Environment Programme, Washington DC, USA, <nowiki>https://wayback.archive-it.org/12090/20230311043000/https://ec.europa.eu/environment/enveco/pdf/eftec_habitat_exec_sum.pdf</nowiki></ref> The steps of the mitigation hierarchy (and terms used to describe them) vary regionally and across fields.<ref name=":0">{{Cite web |last=WWF |date=2020-04-27 |title=First Things First: Avoid, Reduce … and only after that–Compensate |url=https://wwf.panda.org/wwf_news/?362819/First-Things-First-Avoid-Reduce--and-only-after-thatCompensate |access-date=2024-07-01 |website=WWF}}</ref> In [[Environmental impact assessment|Environmental Impact Assessments]], to which it is commonly applied, the mitigation hierarchy generally includes the following steps:<ref>{{Cite journal |last1=Arlidge |first1=William N S |last2=Bull |first2=Joseph W |last3=Addison |first3=Prue F E |last4=Burgass |first4=Michael J |last5=Gianuca |first5=Dimas |last6=Gorham |first6=Taylor M |last7=Jacob |first7=Céline |last8=Shumway |first8=Nicole |last9=Sinclair |first9=Samuel P |last10=Watson |first10=James E M |last11=Wilcox |first11=Chris |last12=Milner-Gulland |first12=E J |date=2018-05-01 |title=A Global Mitigation Hierarchy for Nature Conservation |url=https://academic.oup.com/bioscience/article/68/5/336/4966810 |journal=BioScience |language=en |volume=68 |issue=5 |pages=336–347 |doi=10.1093/biosci/biy029 |issn=0006-3568 |pmc=5925785 |pmid=29731513}}</ref><ref>{{Cite web |title=Mitigation Hierarchy |url=https://nationalzoo.si.edu/ccs/mitigation-hierarchy |access-date=2024-08-02 |website=Smithsonian's National Zoo and Conservation Biology Institute |language=en}}</ref>

* '''Avoid''' - measures taken to avoid creating impacts. This step is widely regarded as the most important.<ref>{{Cite journal |last1=Phalan |first1=Ben |last2=Hayes |first2=Genevieve |last3=Brooks |first3=Sharon |last4=Marsh |first4=David |last5=Howard |first5=Pippa |last6=Costelloe |first6=Brendan |last7=Vira |first7=Bhaskar |last8=Kowalska |first8=Aida |last9=Whitaker |first9=Samir |date=2018 |title=Avoiding impacts on biodiversity through strengthening the first stage of the mitigation hierarchy |url=https://www.cambridge.org/core/product/identifier/S0030605316001034/type/journal_article |journal=Oryx |language=en |volume=52 |issue=2 |pages=316–324 |doi=10.1017/S0030605316001034 |issn=0030-6053}}</ref>
* '''Minimise''' - measures to reduce impacts that cannot be avoided.
* '''Restore/rehabilitate''' - measures to restore or rehabilitate ecosystems that have been cleared or degraded, following a development project/activity that caused impacts that could not be avoided or minimised. [[Ecological restoration|Restoration]] involves assisting the recovery of an ecosystem that has been degraded, damaged or destroyed.<ref>{{Cite journal |last1=Bullock |first1=James M. |last2=Aronson |first2=James |last3=Newton |first3=Adrian C. |last4=Pywell |first4=Richard F. |last5=Rey-Benayas |first5=Jose M. |date=2011 |title=Restoration of ecosystem services and biodiversity: conflicts and opportunities |url=https://linkinghub.elsevier.com/retrieve/pii/S0169534711001777 |journal=Trends in Ecology & Evolution |language=en |volume=26 |issue=10 |pages=541–549 |doi=10.1016/j.tree.2011.06.011|pmid=21782273 |bibcode=2011TEcoE..26..541B |hdl=10017/40628 |hdl-access=free }}</ref>
* '''Offset''' - measures to compensate for residual negative impacts that cannot be avoided, minimised, or restored/rehabilitated, generally with the aim of no net loss or net gain of biodiversity.

The importance of applying these steps in order to effectively achieve conservation goals or policy aims (such as no net loss and net gain) has been emphasised.<ref>{{Cite web |last=Mackie |first=Harriet |date=2024-04-30 |title=Mitigation Hierarchy: Explanation & Stages |url=https://gaiacompany.io/mitigation-hierarchy-explanation-stages/ |access-date=2024-08-02 |website=Gaia |language=en-GB}}</ref> 
[[File:Hiearchy of recovery options for mitigating food waste to landfills.JPG|alt=The methods are in order of preference from top to bottom. The Food Waste Recovery Hierarchy serves as an aspirational guide for waste minimization efforts. |thumb|Application of the mitigation hierarchy as a tool to deal with food waste.]]
An increasing number of policies apply the principles of the mitigation hierarchy to [[Environmental impact assessment|environmental impact assessments]] that address the impacts of businesses and governments on the environment, including on [[biodiversity]] and [[Ecosystem service|ecosystem services]].<ref>{{Cite journal |last1=Milner-Gulland |first1=E.J. |last2=Addison |first2=Prue |last3=Arlidge |first3=William N.S. |last4=Baker |first4=Julia |last5=Booth |first5=Hollie |last6=Brooks |first6=Thomas |last7=Bull |first7=Joseph W. |last8=Burgass |first8=Michael J. |last9=Ekstrom |first9=Jon |last10=zu Ermgassen |first10=Sophus O.S.E. |last11=Fleming |first11=L. Vincent |last12=Grub |first12=Henry M.J. |last13=von Hase |first13=Amrei |last14=Hoffmann |first14=Michael |last15=Hutton |first15=Jonathan |date=2021 |title=Four steps for the Earth: mainstreaming the post-2020 global biodiversity framework |url=https://doi.org/10.1016/j.oneear.2020.12.011 |journal=One Earth |volume=4 |issue=1 |pages=75–87 |doi=10.1016/j.oneear.2020.12.011 |bibcode=2021OEart...4...75M |issn=2590-3322}}</ref> In this context, the mitigation hierarchy is usually applied with the goal of achieving [[No net loss wetlands policy|no net loss]]. In some jurisdictions, the application of the mitigation hierarchy is required by law.<ref>{{Cite web |date=2010 |title=Biodiversity offsets and the mitigation hierarchy: a review of current application in the banking sector |url=https://www.unepfi.org/fileadmin/documents/biodiversity_offsets.pdf |access-date=2024-08-02 |website=United Nations Environment Programme Finance Initiative}}</ref> Requirements for compliance with the mitigation hierarchy are often embedded within regulations to govern [[Environmental impact assessment|Environmental Impact Assessments]] and environmental licensing systems to evaluate and mitigate the environmental impacts of economic development.<ref>{{Cite journal |last1=Villarroya |first1=Ana |last2=Barros |first2=Ana Cristina |last3=Kiesecker |first3=Joseph |date=2014-09-05 |title=Policy Development for Environmental Licensing and Biodiversity Offsets in Latin America |journal=PLOS ONE |language=en |volume=9 |issue=9 |pages=e107144 |doi=10.1371/journal.pone.0107144 |doi-access=free |issn=1932-6203 |pmc=4156437 |pmid=25191758|bibcode=2014PLoSO...9j7144V }}</ref> 

Variations to the classical mitigation hierarchy have been proposed, like the Mitigation and Conservation Hierarchy and the Science Based Target Network's AR3T framework.<ref>{{Cite journal |last=Milner-Gulland |first=E.J. |last2=Addison |first2=Prue |last3=Arlidge |first3=William N.S. |last4=Baker |first4=Julia |last5=Booth |first5=Hollie |last6=Brooks |first6=Thomas |last7=Bull |first7=Joseph W. |last8=Burgass |first8=Michael J. |last9=Ekstrom |first9=Jon |last10=zu Ermgassen |first10=Sophus O.S.E. |last11=Fleming |first11=L. Vincent |last12=Grub |first12=Henry M.J. |last13=von Hase |first13=Amrei |last14=Hoffmann |first14=Michael |last15=Hutton |first15=Jonathan |date=2021 |title=Four steps for the Earth: mainstreaming the post-2020 global biodiversity framework |url=https://doi.org/10.1016/j.oneear.2020.12.011 |journal=One Earth |volume=4 |issue=1 |pages=75–87 |doi=10.1016/j.oneear.2020.12.011 |issn=2590-3322}}</ref><ref>{{Cite web |title=Act |url=https://sciencebasedtargetsnetwork.org/companies/take-action/act/ |access-date=2024-08-08 |website=Science Based Targets Network |language=en-US}}</ref> In addition to its use for biodiversity, alternate versions of the mitigation hierarchy have been proposed for different sectors, such as waste, food waste, energy, and carbon.<ref name=":0" />

== Environmental mitigation in the United States ==
{{Further information|Mitigation banking|Conservation banking}}The [[Fish and Wildlife Coordination Act]] in 1934 included the first legal expressions of the duty to minimise and compensate for negative environmental impacts.<ref name=":02">{{Cite web |date=2016-10-04 |title=Environmental Mitigation Regulations {{!}} U.S. Department of the Interior |url=https://www.doi.gov/ocl/environmental-mitigation-regulations |access-date=2024-08-02 |website=www.doi.gov |language=en}}</ref><ref name=":12">Veiluva, Michael. (1981). The fish and wildlife coordination act in environmental litigation. Ecology Law Quarterly, 9(3), 489-518.</ref> The act was a response to the impacts of rapid urban expansion and dam building in the US on salmon and other migratory fish.<ref name=":02" /><ref name=":12" /> These efforts were later expanded on with the introduction of the [[National Environmental Policy Act]] of 1969 and with other regulations that require compensatory mitigation for some projects.

In the United States, compensatory mitigation is a commonly used form of environmental mitigation and, for some projects, it is legally required under the [[Clean Water Act|Clean Water Act 1972]]. Compensatory mitigation is defined by the [[United States Department of Agriculture|US Department of Agriculture]] as "measures to restore, create, enhance, and preserve wetlands to offset unavoidable adverse impacts."<ref>{{Cite web |last=National Resources Conservation Service |first=US Department of Agriculture |date=2024-08-02 |title=Conservation compliance glossary |url=https://www.nrcs.usda.gov/resources/guides-and-instructions/conservation-compliance-glossary |access-date=2024-08-02 |website=National Resources Conservation Service, US Department of Agriculture}}</ref> Early wetland compensatory mitigation was regarded as a failure.

One of the main methods of compensatory mitigation in the US is [[mitigation banking]], a market-based method to offset adverse impacts to wetlands (or streams and other bodies of water) that cannot be either avoided or reduced.<ref>{{Cite web |last=United States Environmental Protection Agency |date=2024-08-02 |title=Wetlands Compensatory Mitigation |url=https://www.epa.gov/sites/default/files/2021-01/documents/wetlands_compsatory_mitigation.pdf |access-date=2024-08-02}}</ref> This is done by selling credits from mitigation banks, which are sites where activities to preserve, enhance, create, or restore aquatic habitat are conducted and valued in the form of credits. Developers can purchase credits from mitigation banks to offset the "debit" of negative environmental impacts with the aim of achieving no net loss of wetlands. [[No net loss wetlands policy|No net loss]] is the policy objective used to guide compensatory mitigation in the United States, but has since expanded to other countries, where no net loss of biodiversity may be required as the aim of environmental mitigation measures like biodiversity offsets.<ref name=":6">{{Cite journal |last=zu Ermgassen |first=Sophus Olav Sven Emil |last2=Utamiputri |first2=Pratiwi |last3=Bennun |first3=Leon |last4=Edwards |first4=Stephen |last5=Bull |first5=Joseph William |date=2019 |title=The Role of “No Net Loss” Policies in Conserving Biodiversity Threatened by the Global Infrastructure Boom |url=https://doi.org/10.1016/j.oneear.2019.10.019 |journal=One Earth |volume=1 |issue=3 |pages=305–315 |doi=10.1016/j.oneear.2019.10.019 |issn=2590-3322|doi-access=free }}</ref>

[[Conservation banking]] is also used in the United States in the context of endangered species under the [[Endangered Species Act of 1973]] as a form of compensatory mitigation.<ref>{{Cite journal |last1=White |first1=Thomas B. |last2=Bull |first2=Joseph W. |last3=Toombs |first3=Theodore P. |last4=Knight |first4=Andrew T. |date=2021 |title=Uncovering opportunities for effective species conservation banking requires navigating technical and practical complexities |url=https://conbio.onlinelibrary.wiley.com/doi/10.1111/csp2.431 |journal=Conservation Science and Practice |language=en |volume=3 |issue=7 |doi=10.1111/csp2.431 |bibcode=2021ConSP...3E.431W |issn=2578-4854}}</ref>

== Biodiversity offsetting ==
{{Main article|Biodiversity offsetting}}
[[Biodiversity offsetting]] is an environmental mitigation measure defined by the Business and Biodiversity Offsets Programme as "measurable conservation outcomes of actions designed to compensate for significant residual adverse biodiversity impacts arising from project development after appropriate prevention and mitigation measures have been taken."<ref name=":8" /> It is put forward as the final step of the mitigation hierarchy and regulations require that it is applied only after measures to avoid or reduce impacts.<ref name=":7" />

It is an increasingly popular method of environmental mitigation for businesses and developers, though its suitability and success is debated.<ref>{{Cite web |date=2023-12-05 |title=Does biodiversity offsetting work? |url=https://www.britishecologicalsociety.org/does-biodiversity-offsetting-work/ |access-date=2024-08-08 |website=British Ecological Society |language=en-GB}}</ref> More than 100 countries worldwide have biodiversity offsetting requirements and, elsewhere, biodiversity offsetting may be applied as part of lending requirements from international financial institutions like the [[World Bank]] or as a voluntary commitment by businesses.<ref name=":9" /> 

== Environmental crediting systems ==
{{See also|Biodiversity banking|Mitigation banking}}Environmental mitigation might be conducted using an environmental crediting system (like a biodiversity banking framework) established by governing bodies that allocate [[debits and credits]]. Examples of such systems include [[biodiversity banking]] (a way to carry out [[biodiversity offsetting]]) and its various forms, including [[mitigation banking]], habitat banking, species banking, or [[conservation banking]], dependent on region or the goals of the system for conservation.<ref>{{Cite journal |last=Froger |first=Géraldine |last2=Ménard |first2=Sophie |last3=Méral |first3=Philippe |date=2015-10-01 |title=Towards a comparative and critical analysis of biodiversity banks |url=https://www.sciencedirect.com/science/article/pii/S2212041614001570 |journal=Ecosystem Services |volume=15 |pages=152–161 |doi=10.1016/j.ecoser.2014.11.018 |issn=2212-0416|url-access=subscription }}</ref><ref name=":2" /> This might be done with a specific objective, such as [[No net loss wetlands policy|no net loss of wetlands]] for mitigation banking in the United States or no net loss of biodiversity for habitat banks in Colombia.<ref name=":3">{{Cite web |title=Mitigation Trade: Making Up for Environmental Harm |url=https://www.investopedia.com/articles/dictionary/031615/understanding-basics-mitigation-banking.asp |access-date=2024-08-06 |website=Investopedia |language=en}}</ref><ref>{{Cite web |last=Colombia |first=Ministerio de Ambiente y Desarrollo Sostenible |date=2018 |title=Bancos de Hábitat |url=https://www.minambiente.gov.co/wp-content/uploads/2021/10/Compensaciones-Gui%CC%81a-Bancos-de-Ha%CC%81bitat.pdf |access-date=2024-08-06 |website=Minambiente}}</ref>  

Credits are generated by banks where a natural resource has been deemed to be improved through conservation or preservation activities at the bank site.<ref>{{Cite web |title=Conservation and Mitigation Banking |url=https://wildlife.ca.gov/Conservation/Planning/Banking |access-date=2024-08-06 |website=wildlife.ca.gov}}</ref> Debits arise where significant adverse environment impacts (such as degradation of a habitat or damage to a natural resource) are planned at a permitted site.<ref name=":5">{{Cite web |date=2022-11-01 |title=Mitigation Banking 101: How Does Mitigation Banking Work? |url=https://mitigationbankinginc.com/mitigation-banking-101-how-does-mitigation-banking-work/ |access-date=2024-08-06 |website=The Mitigation Banking Group |language=en-US}}</ref> Where a business or individual has a debit, they might be required to purchase a credit to offset an impact that cannot be otherwise avoided or reduced.<ref name=":5" /> For example, England's Biodiversity Net Gain policy requires that developers purchase biodiversity credits from the government if they are unable to achieve a 10% gain in biodiversity by creating or enhancing habitat on their development site.<ref>{{Cite web |date=2024-02-22 |title=Understanding biodiversity net gain |url=https://www.gov.uk/guidance/understanding-biodiversity-net-gain |access-date=2024-08-06 |website=GOV.UK |language=en}}</ref> Some entities might also purchase credits form these systems voluntarily.<ref>{{Cite web |last=Pollination |date=2023 |title=State of Voluntary Biodiversity Credit Markets |url=https://pollinationgroup.com/wp-content/uploads/2023/10/Global-Review-of-Biodiversity-Credit-Schemes-Pollination-October-2023.pdf |access-date=2024-08-06 |website=Pollination Group}}</ref>

An example of an environmental crediting system is the [[mitigation banking]] system in the United States.<ref name=":4">{{Cite web |last=US EPA |first=OW |date=2015-06-16 |title=Mitigation Banks under CWA Section 404 |url=https://www.epa.gov/cwa-404/mitigation-banks-under-cwa-section-404 |access-date=2024-08-06 |website=www.epa.gov |language=en}}</ref> This system tends to be used to compensate for impacts on wetlands and other aquatic habitats in advance of their occurrence.<ref name=":4" /> It is the preferred method for compensatory mitigation under guidelines set by the [[United States Environmental Protection Agency|EPA]] (Environmental Protection Agency) and [[United States Army Corps of Engineers|US Army Corps of Engineers]] - the agencies tasked with regulating mitigation banking in the United States.<ref>Hough, Palmer, and Rachel Harrington. "Ten years of the compensatory mitigation rule: reflections on progress and opportunities." ''Envtl. L. Rep. News & Analysis'' 49 (2019): 10018.</ref> As part of this system, credits are purchased from mitigation banks by anyone who incurs a debit from impacts to wetlands and other aquatic habitats that cannot otherwise be avoided or reduced.<ref name=":3" /> Mitigation banks are sites where mitigation projects have been carried out, such as preservation, enhancement, restoration, or habitat creation.<ref>{{Cite web |last=Washington State Department of Ecology |date=2007 |title=Frequently Asked Questions about Wetland Mitigation Banking |url=https://apps.ecology.wa.gov/publications/documents/0706013.pdf |access-date=2024-08-06 |website=Washington State Department of Ecology}}</ref>

Separate from biodiversity offsetting, nature credits might be purchased as a way for companies to achieve environmental commitments (such as commitments to work towards a [[Nature-positive|nature positive]] economy) by helping to fund initiatives like the [[Kunming-Montreal Global Biodiversity Framework]] or national biodiversity strategies.<ref>{{Cite web |title=Nature Credit Markets |url=https://www.conservation.org/projects/nature-credit-markets |access-date=2024-08-08 |website=www.conservation.org}}</ref><ref>{{Cite journal |last=Swinfield |first=Tom |last2=Shrikanth |first2=Siddarth |last3=Bull |first3=Joseph W. |last4=Madhavapeddy |first4=Anil |last5=zu Ermgassen |first5=Sophus O. S. E. |date=2024-08-06 |title=Nature-based credit markets at a crossroads |url=https://www.nature.com/articles/s41893-024-01403-w |journal=Nature Sustainability |language=en |pages=1–4 |doi=10.1038/s41893-024-01403-w |issn=2398-9629}}</ref>

=== Issues ===
Determining the currency that a system will be based on and ensuring that debits and credits are ecologically equivalent are considered challenging issues for environmental crediting systems.<ref>{{Cite journal |last=White |first=Thomas B. |last2=Bull |first2=Joseph W. |last3=Toombs |first3=Theodore P. |last4=Knight |first4=Andrew T. |date=2021 |title=Uncovering opportunities for effective species conservation banking requires navigating technical and practical complexities |url=https://conbio.onlinelibrary.wiley.com/doi/10.1111/csp2.431 |journal=Conservation Science and Practice |language=en |volume=3 |issue=7 |doi=10.1111/csp2.431 |issn=2578-4854}}</ref> There is no single agreed upon method for determining the value of credits to ensure that biodiversity lost and gained have an equivalent value.<ref>{{Cite web |date=2024-02-01 |title=Drivers of loss: a way forward for biodiversity claims? |url=https://bezerocarbon.com/insights/drivers-of-loss-a-way-forward-for-biodiversity-claims |access-date=2024-08-08 |website=BeZero Carbon |language=en}}</ref> Ensuring that the outcomes of conservation projects used to generate credits are better for biodiversity than if the projects had not happened (a concept called additionality) is another challenge.<ref>{{Cite web |last=Galeano |first=Victoria |date=2024-06-17 |title=Nature’s Currency: How Biodiversity Credits are Reshaping Conservation |url=https://latintrade.com/2024/06/17/natures-currency-how-biodiversity-credits-are-reshaping-conservation/ |access-date=2024-08-08 |website=Latin Trade |language=en-US}}</ref> 

One reason for this is the complexity of assessing the value of biodiversity, such as in terms of ecosystem services, both across different habitats and over time in the same habitat.<ref>{{Cite web |title=Measuring Biodiversity: The Quest for a Common Metric |url=https://www.climateimpact.com/news-insights/insights/measuring-biodiversity-the-quest-for-a-common-metric/ |access-date=2024-08-08 |website=www.climateimpact.com |language=en-gb}}</ref> The principle of quantifying biodiversity value by using credit and debit units is debated, with some people considering it an impossible task or reject the idea for ethical reasons.<ref>{{Cite web |date=2023-09-07 |title=Biodiversity credits: everything you need to know |url=https://www.britishecologicalsociety.org/biodiversity-credits-everything-you-need-to-know/ |access-date=2024-08-06 |website=British Ecological Society |language=en-GB}}</ref><ref>{{Cite journal |last=Maron |first=Martine |last2=Ives |first2=Christopher D. |last3=Kujala |first3=Heini |last4=Bull |first4=Joseph W. |last5=Maseyk |first5=Fleur J. F. |last6=Bekessy |first6=Sarah |last7=Gordon |first7=Ascelin |last8=Watson |first8=James E.M. |last9=Lentini |first9=Pia E. |last10=Gibbons |first10=Philip |last11=Possingham |first11=Hugh P. |last12=Hobbs |first12=Richard J. |last13=Keith |first13=David A. |last14=Wintle |first14=Brendan A. |last15=Evans |first15=Megan C. |date=2016-04-13 |title=Taming a Wicked Problem: Resolving Controversies in Biodiversity Offsetting |url=https://doi.org/10.1093/biosci/biw038 |journal=BioScience |volume=66 |issue=6 |pages=489–498 |doi=10.1093/biosci/biw038 |issn=0006-3568|url-access=subscription }}</ref> 

The use of credit ratios has been proposed as a method to address uncertainties.<ref name=":2" /> In the United States, regulators often assign 'mitigation ratios' in the case of compensatory mitigation agreements. The ratio is used to compare the acres of wetland impacted at a development site with the gains at the proposed mitigation bank to determine how many mitigation credits are needed to achieve no net loss or better.<ref name=":5" /> For example, coverage ratios of 3:1 would require 3 compensatory mitigation credits for each unit of "debit" caused by an [[ecological disturbance]]. 

==See also==
*[[Mitigation]]
*[[Mitigation banking]]
*[[Environmental impact assessment|Environmental Impact Assessment]]
*[[Biodiversity offsetting]]
*[[Biodiversity banking]]
*[[Biodiversity loss]]
*[[Climate change mitigation]]
*[[No net loss environmental policy]]

== References ==
{{reflist}}
==External links==
* [http://www.epa.gov/wetlandsmitigation/ United States EPA Compensatory Mitigation website]
* [http://www.mitigationbanking.org/ National Mitigation Banking Association]
* [http://edocket.access.gpo.gov/2008/pdf/E8-17579.pdf/ Endangered Species and Threatened Wildlife and Plants; Recovery Crediting Guidance]

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