A scoping review of equitable climate adaptation research in U.S. cities

As cities continue to prepare for climate change by developing adaptation plans, previous research has examined the content, creation, and considerations of equity and justice in these plans, particularly across United States cities. Climate adaptation activities create the potential for undue harm on marginalized populations, therefore it is important to understand the state of knowledge on equitable climate adaptation as cities begin implementing their plans. We conducted a scoping review of 15 journal articles on equitable adaptation in United States cities to document theoretical frameworks used and major findings. Studies included in our sample primarily used three different theoretical frameworks, including environmental justice theory, neoliberal urban governance, or just sustainabilities, to analyze how plans were created and their contents. Studies we analyzed indicate that cities were successful at identifying problems or challenges but struggled with articulating how to best engage residents and community members or to grapple with systemic issues. We also developed best practices for adaptation based on recommendations from the studies: have clear implementation guidelines, invest in frontline communities, regulate the private sector, work with community-based organizations, and develop regional planning initiatives. Overall, the state of knowledge is such that cities have taken the first step of creating adaptation plans, but how these plans are implemented will make the true difference for equitable outcomes.


Introduction
Across the world, city populations are rapidly growing.In the United States alone, the urban population has increased 6.4%, representing more than 20 million people, between the 2010 Census and the 2020 Census and 80% of the U.S. population now lives in urban areas (US Census Bureau 2023).With more people in cities, there has been an increase in demand for resources, amenities, and municipal services (Dodman et al 2022).Inequality has grown alongside cities, meaning gaps between people with access to resources and those without are increasing (Grusky and Ku 2008).Population groups most likely to lack access to resources include minoritized races and ethnicities and those with low incomes.At the same time, the climate continues to warm, leaving cities, and some of their residents-those same population groups (i.e.low-income people and communities of color)-vulnerable to the impacts of climate change.Urban areas are likely to experience hotter temperatures (Debbage and Shepherd 2015) and more flooding as precipitation becomes less frequent but more intense, overwhelming stormwater management systems (Moore et al 2016).To address climate change, cities are developing climate adaptation plans (e.g.Betsill and Bulkeley 2005, Bassett and Shandas 2010, Stults and Woodruff 2017), and these plans can also include considerations of equity and justice in response to the uneven impacts of climate change (e.g.Hughes 2020).
Scholarship on equitable climate adaptation, mitigation, and resilience has grown in the last decade.However, this work needs to be collated and synthesized to provide an understanding of what has been discovered so far in this area of research.This study thus summarized and synthesized the scholarly work on equitable adaptation, mitigation, and resilience from the peer-reviewed literature, with a focus on U.S. cities.
Climate adaptation plans are policy-like documents created by cities to describe what the city hopes to do, or actively plans to do, in order to adapt their infrastructure and systems to impending climate change.Example strategies for climate adaptation and mitigation include increasing renewable energy, improving waste management, planting trees and vegetation for shade, roof coating, installing green infrastructure for stormwater management, or improving efficiency in city buildings.Additionally, cities include considerations of equity and justice in their goals, though how implementation will occur often still remains unclear (Mullenbach and Wilhelm Stanis 2022).This poses problems for equity and justice.
Without clear implementation strategies, people who are marginalized and lack resources or political capital are left to face adaptation and resilience challenges without the express support of their local government (Anguelovski et al 2016, Rice et al 2022, Pratt 2023).For instance, climate gentrification is one such injustice that adaptation may catalyze.Climate gentrification is the rapid onset of high rent prices and property values following investments in a neighborhood, leading to displacement of low-income and otherwise vulnerable residents.Many such residents are forced to move to areas without resources.The investments which may catalyze gentrification can include adaptation infrastructure, such as energy efficient buildings, green spaces and parks, bus routes, and other amenities (Anguelovski et al 2019).Therefore, the strategies cities identify and implement can also increase inequality when they prioritize the needs of wealthy elites and other powerful decision-makers over the people most at risk (Meerow et al 2019).Oftentimes, adaptation plans incorporate strategies to increase economic development in cities.Since the economy itself is unequal, pursuing more economic growth-and by extension more inequality-brings into question how adaptation will occur without causing further harm and more vulnerability (Akers et al 2020, Ehrenfeucht andNelson 2020).
Particularly susceptible to the pressures of economic growth while needing to consider equity and justice are legacy cities (Ehrenfeucht andNelson 2020, Silverman 2020).These cities have experienced the transition from industrial to post-industrial local economies, such as those in the Rust Belt.As a result of this economic decline, residents who were able to move out of legacy cities did so, leaving the most vulnerable and marginalized residents behind (Ganning and Tighe 2021).Climate adaptation planning may allow legacy cities to communicate they are desirable places if they consider equity and justice in the planning process (Sampson 2014, Hughes 2020, Ortiz-Moya 2020).However, legacy cities might also pursue economic development under the guise of climate adaptation, further exacerbating inequality (Akers et al 2020, Ehrenfeucht and Nelson 2020, Silverman 2020).Alternatively, legacy cities could use climate adaptation as an opportunity to reinvent themselves with progressive policies (Sampson 2014, Ortiz-Moya 2020).
In addition to inequities and exacerbation of vulnerability, cities can also fall short of adaptation by not taking enough action or by taking action that is not successful or actually harmful-some researchers refer to this as maladaptation (Barnett and O'Neill 2010).An apt example of maladaptation would be climate gentrification, as previously described.There are thus multiple ways cities can misstep, necessitating an understanding of what strategies and approaches lead to the most equitable and just outcomes and avoid harm to vulnerable populations.Cities also face multiple challenges when planning their climate responses that can make it more difficult to create a plan.For example, a wealth of available climate information to sift through can be daunting to decision-makers (Moser and Ekstrom 2010).Similarly, projections of future climates are often only available at large spatial scales, making it hard to understand the specific impacts a given city might face (Archie et al 2014).Additionally, finding funding for adaptation, and determining who will pay for any given action, can leave cities stuck in a stalemate.Some places might have a staff of grant writers who are able to apply for federal funding, while others must navigate that process on their own (e.g.Ekstrom and Moser 2014).In politically conservative places, adaptation may be unpalatable and unpopular, forcing decision-makers to determine how to discuss adaptation options without saying the words 'climate change' (e.g.Geiger et al 2017).These are only a few of the problems cities might face when writing and implementing an adaptation plan.These difficulties can put equity and justice on the backburner, reducing the equity in outcomes.
There are three different theoretical frameworks that scholars have used in research on equitable climate adaptation: environmental justice (EJ), neoliberal urban governance, and just sustainabilities.We provide more discussion of how scholars use these frameworks in our Findings section, but first we define them here.EJ considers how environmental harms and amenities are distributed (distributive justice), who has access to decision-making and planning processes (procedural justice) and recognizing past injustices and systemic inequities (recognition justice) (Schlosberg 2013).Neoliberalism is the idea that the free market is the best and most effective way to organize society and the government, resulting in rollbacks of social services and increased reliance on private entities for city services (e.g.Harvey 2007a, Brown 2019, Joy and Vogel 2021).Finally, just sustainabilities, developed by Agyeman and Evans (2003) builds on the EJ framework and argues that sustainability should include considerations of race and inequality, in order to develop a redistributive function within sustainability initiatives.All of these theoretical frameworks have been used to understand how cities are preparing to adapt to climate adaptation.Since these theoretical frameworks are used often within the field of scholars studying equitable climate adaptation, we kept track of how researchers in this area use them, and they guided our assessment of what we, as a body of researchers, know about how cities are approaching equity within climate adaptation planning.

Study purpose
Given the importance of climate adaptation, and the potential for undue harm on marginalized populations, we need to understand the state of knowledge on equitable climate adaptation.As seen in the proliferation of adaptation plans and the growing emphasis on equity and justice, this topic has become quite popular in academic literature.Many scholars are studying the content of adaptation plans and how cities are implementing their strategies.Synthesizing this literature is necessary to clarify gaps, create collective understanding, and enables best practices from cities across the country, presenting an opportunity for scholars and cities to learn from one another.Because of this dual purpose, our intended audience is both scholars (who may benefit from an understanding of our gaps in knowledge and different theoretical approaches) and practitioners and policy-makers (who may benefit from the best practices).Through a scoping review, this paper provides a summary of what types of issues and strategies that scholars have found U.S. cities using in their plans and suggests possible best practices.We also note that there are some differences between climate adaptation, mitigation, and resilience.Since our scoping review addresses all three, we frame our manuscript such that we describe how scholars study them and how decision-makers may attempt them-and collectively we term this 'climate responses.'

Methods
In accordance with scoping review guidelines, we used the academic databases Academic Search Complete and Web of Science via the University of Oklahoma library to search for relevant journal articles (e.g.Moher et al 2009).We limited results to publications in peer-reviewed journals and those published in the last decade (anything after 1st January 2013).Additionally, because we are focused on climate adaptation in United States cities, we only kept papers that are centered on U.S. cities and their adaptation efforts.When searching the databases, we searched for all possible combined sets of keywords, which included 'climate adaptation' and equity, 'sustainability plan * ' and equity, 'climate adaptation' and urban, and 'climate adaptation' and 'EJ.' Searches were conducted on 21st August 2023.The next step encompassed determining which articles were kept for analysis, depicted in figure 1.When searching the databases, we screened titles for relevance, documenting when they were published, as well as author and journal information.After using all possible combinations of keywords in each database, we created a spreadsheet of papers that passed the title screening.The next step included reading each of the abstracts of papers and further determining their relevance.For example, a paper that studies an area outside of the United States might have passed the first-round title review but would not pass the second round.If a paper was deemed relevant after reading its abstract, we wrote a brief summary of the abstract and key findings.Then, we read each of the papers that were kept in the second stage of review and wrote a brief annotated bibliography.While reading fulltext articles, we determined whether an article was empirical or conceptual.We set aside any papers that were conceptual, rather than producing data themselves, and chose not to consider them for this analysis.We documented methods and major findings of the empirical papers, as well as suggestions for more equitable climate adaptation.After this step, we synthesized findings from the empirical papers to conclude what is known about equitable climate adaptation and resilience in United States' cities and created several best practices.

Findings
Our results are split into two main sections: findings that are applicable and relevant to other scholars and researchers, and findings that are applicable and relevant to practitioners and cities.First, we outline how previous research has examined content of adaptation plans, then describe their main findings, and lastly we provide suggestions for future development of such plans.Papers included in this review are listed in table 1.The studies we evaluated indicate that cities are considering many challenges, both environmental and social, are offering solutions in their climate adaptation plans, and are influenced by multiple actors when developing them.

Conceptual frameworks
Most of the studies used the EJ framework to analyze climate adaptation plans or to create an adaptation justice index.However, authors varied in the exact form that their EJ framework took on.Meerow et al (2019) adapted the EJ framework to be centered on equity, renaming the prongs of EJ as distributive, procedural, and recognitional equity.Chu and Cannon (2021) frame their analysis in equity, inclusion, and justice considerations in different plans.While they use different words to describe qualities of adaptation plans, their definition of these categories overlaps with the EJ framework.When analyzing equity, they investigate how plans focus on inequality and vulnerability, and how these risks are distributed across space (distributive justice).Their assessment of inclusion focused on the participatory processes that were used in the creation of the plans (procedural justice).Finally, their examination of justice included whether or not plans recognized differential vulnerability to climate change and if they articulated anti-racist approaches to adaptation (recognitional justice).Other studies applied the EJ framework to their specific focus within plans or a certain geographic area (Hughes 2020, Rudge 2021, Shi 2021, Mullenbach and Wilhelm Stanis 2022).
Other framings that studies used included neoliberalism and just sustainabilities.Fainstein (2018) used neoliberalism to assess resilience planning and justice in New York City, particularly how this ideology has shaped the city's definition of resilience over time.She finds that New York City has restricted resilience to only include the physical environment while also focusing on economic development and real estate as a means to increase investment and draw in capital.Only economically valuable areas are identified as worthy of adaptation investment in New York City plans, further emphasizing how the wealthy and economic interests are preserved at the expense of poor residents of color.Fiack et al (2021) draw on Agyeman and Evans (2003) definition of just sustainabilities to assess how much cities prioritize social equity and sustainable development in their plans.They found that cities give distributive considerations of justice the most attention, followed by procedural justice, and that cities emphasize growth and development alongside environmental benefits (Fiack et al 2021).For many cities, it is clear that adaptation is approached as a vehicle through which economic growth and development can occur.

Methods used
Many of the studies we analyzed discussed the content of climate adaptation plans, particularly how cities are including considerations of equity and justice in their planning documents (Schrock et al 2015, Fainstein 2018, Meerow et al 2019, Chu and Cannon 2021, Fiack et al 2021, Hess and McKane 2021, Mullenbach and Wilhelm Stanis 2022, Cannon et al 2023).One study also analyzed reports from different organizations about how cities can enhance equity and justice in their plans (Shi 2021).When analyzing plan contents, studies most frequently used content analysis or discourse analysis to assess how various components of the plans would or would not increase equity.Cities represented in our sample of studies tended to be located along the eastern and western coasts of the United States, with very little representation of cities in the Northern Rockies and Plains, Southeast, or Northwest.Six states (Wyoming, Idaho, North Dakota, South Dakota, Kansas, and Alabama) were not included in any studies.Twenty-one states were only represented in one study, meaning that over half the country was either not included or were understudied compared to other cities and states.The top ten cities studied were New York City (7), Boston, (6), Atlanta (5), Chicago (4), Cleveland (4), Los Angeles (4), Miami (4), Philadelphia (4), Washington D.C. (4), and Dallas (3).The top ten cities represent just under six percent of the total U.S. population, while all of the cities that were analyzed across the studies represent 15% of the U.S. population.For reference, 80% of the U.S. lives in what the Census Bureau describes as an urban area.Scholars may consider conducting future research on a greater swath of the U.S. urban population to obtain a more accurate picture of contemporary climate adaptation planning.

What do the plans say?
Based on our assessment of the studies included in our review, climate adaptation plans-and related plans (e.g.climate action plans; climate resilience plans)-contained many types of information.Most often, authors of studies in our review stated that cities began their plan with an outline of economic, social, and climate vulnerabilities and how climate change will impact the city.Some described how they engaged residents and other community organizations in the planning process.The studies in our sample indicated that after presenting this introductory material, cities would often outline strategies they intended to use for climate adaptation, ranging in topic from housing, transportation, waste management, or renewable energy, among many others (Hess and McKane 2021).In many instances, study authors indicated that equity was viewed as a cobenefit of adaptation and resilience, not a separate goal to strive for via climate response measures (Schrock et al 2015).Even with an equity and justice emphasis, plans analyzed in the studies in our sample also featured economic growth as a key motivator, with several strategies being centered on drawing in businesses or investment (Fiack et al 2021).
The studies encompassed in this review indicate that cities are quite good at identifying their problems, but struggle when it comes to explaining their long-term goals, particularly related to equity and justice implications.Our analysis revealed that cities often describe the types of goals they have in many areas, but researchers of these cities struggled to identify implementation timeframes, funding source, guidelines, and responsible parties (Cannon et al 2023).Additionally, when considering the three prongs of EJ theory, study authors indicated plans least often discussed issues related to recognition justice and acknowledging how systemic racism has shaped their present conditions, though our sample indicated that many cities were able to identify which groups of people were considered vulnerable (Meerow et al 2019, Cannon et al 2023).Our findings also suggest that cities studied by the authors in our sample were more able to articulate strategies aligned with distributive and procedural justice.Distributive justice outcomes tended to receive the most attention in adaptation plans as cities considered where adaptation amenities and harms would be located and how this might disproportionately affect certain groups of people (Fiack et al 2021).However, their engagement processes were not extensive in many cases, and it was unclear how different community organizations or communities of color were included in the planning process outside of attending public meetings (Fainstein 2018, Rudge 2021).
Related to procedural justice, there were many actors who participated in the planning processes of the cities studied in our review.Most often these studies indicated that municipal agencies and planning organizations led the development of the adaptation plan, and that strategies or actions were informed by other participants in the planning process (Cannon et al 2023).These other actors could include community organizations who advocated on behalf of residents (Fainstein 2018, Rudge 2021).Other actors might be universities who provide research support and insight or transnational organizations like the Rockefeller Foundation's 100 Resilient Cities program, who provided resources to many cities to develop their first resilience or adaptation plan.Private partners also contributed, whether they provided research or funding for the creation of the plan (Fainstein 2018).Finally, residents have played a large role in creating adaptation plans, sometimes through participating in public meetings, commenting on the plan, or through a citizen's advisory committee which provides input (Cannon et al 2023).Overall, the studies in our review described how these multiple actors have varying motivations and desired outcomes for the plans and might not always prioritize equitable and just outcomes.Regardless of who participates and how, it is critical for scholars to continue studying these other dimensions of EJ, beyond distributive.The more researchers know about how cities are adapting to climate change, the more we can hold cities accountable when they study climate adaptation planning, to push cities to consider equity and justice at the forefront of the planning process to maintain hope that a plan and its implementation will result in better end results.

Legacy city plans
Previous research has highlighted how legacy cities might be particularly apt to include equity and justice in their climate adaptation plans because they have a higher proportion of residents who are susceptible to the impacts of climate change (Hughes 2020).Additionally, Mullenbach and Wilhelm Stanis (2022) investigated whether legacy cities were talking about health, equity, and justice in their adaptation plans and how this compared to strong market cities.They found that legacy cities included equity and justice in their plans disproportionately more than other cities, which may be explained by the high proportion of health challenges and previous contamination from industrial land uses.
Hughes (2020) also investigated legacy cities and adaptation by conducting two case studies, one in Detroit, Michigan, and another in Cleveland, Ohio using the EJ framework.This work investigated the motivations Detroit and Cleveland had for including equity and justice in their plans and how the three elements of EJ connected to their plans.Both cities in that study used local committees to influence the development of their plans.Detroit inconsistently applied distributive justice principles, but Cleveland framed their plan in racial justice, making direct connections between climate adaptation infrastructure and the most vulnerable communities.Finally, in terms of recognition justice, that study highlighted how Detroit centers vulnerable residents and their Make avenues of participation in adaptation planning clear for community organizations and show how their involvement will benefit the community Regional planning Build networks and relationships among regional partners for a more comprehensive approach to adaptation needs in the framing of their plan but falls short when compared to Cleveland, which views climate adaptation as an opportunity to right previous wrongs.Overall, only a few studies in our review focused on legacy cities, who are developing adaptation plans with equity and justice but can struggle with connecting these ideas to actual programs or goals to implement.More research may reveal to what extent legacy cities are achieving success in this regard-which can then inform other scholarship and other cities.

Practitioner findings 3.2.1. Best practices for adaptation
After describing the types of strategies cities include in their adaptation plans and the implications for equity and justice, papers often outlined suggestions for adaptation and how to make it more equitable in the future.In our analysis, we determined which of the suggestions represented 'best practices' according to EJ principles and compiled them into the categories described below and displayed in table 2. These best practices may help cities overcome the challenges they face in equitable climate responses we mentioned in our introduction.It should be noted that because most of the studies in our review examined large, strong-market cities, many of the suggestions from the authors of these studies tend toward addressing the neoliberalism embedded in larger cities.However, legacy cities have disproportionately more vulnerable residents, and often more inequalities.These best practices, then, should be assessed in future studies to determine their effectiveness in legacy cities.At present, there is insufficient literature on legacy city climate responses, and their impacts, though we feel this merits further consideration in research.

Invest in frontline communities
Another suggestion is for cities to invest in their frontline communities and build their technical capacity to contribute to the plan and empower these communities to build coalitions, blocs, and other groups that can work together to influence climate adaptation efforts (Shi 2021).This is likely to result in more equitable planning processes and has the potential to create more equitable outcomes, depending on plan implementation.Planners working on climate issues should also pay attention to and monitor how implementing plans affects residents, being wary of potential climate gentrification (Meerow and Woodruff 2020).

Regulate the private sector
As for specific actions cities could take, an important one is regulating the private sector and limiting the benefits that are provided to investors and developers.If there is no continued credit or tax incentive developers can exploit, new construction and building may be slower, which will help cities ensure they remain affordable, instead of climate adaptation and more resilient infrastructure leading to gentrification (Shi 2021).Further regulation of the private sector could include requirements on emissions from industrial centers and other businesses or requirements for affordable housing in new developments.Cities could also consider new fees, such as resilience or insurance-based fees, which signal to developers that they should avoid high risk areas or invest in risk reducing measures (Meerow and Woodruff 2020).

Work with community-based organizations
Furthermore, cities can work with community-based organizations during the planning processes, as these organizations often want to participate but are unsure of how to get involved.They may advocate for different communities and needs of residents across the city and their inclusion can make sure those needs are represented in adaptation plans (Fainstein 2018, Rudge 2021).However, cities need to clearly communicate how climate adaptation and resilience planning will help community-based organizations reach their goals and how to best participate in the planning process.
3.2.1.5.Regional planning Finally, regional planning efforts are an opportunity for improvement.In its current state, regional planning tends to take an incremental, business as usual approach, but if re-imagined, regional planning could be a great tool for sharing information and building networks between cities (Shi 2019).Regional partnerships were most successful when they facilitated information sharing among cities, such as opportunities for networking or sharing technical assistance, when they resulted in increased financial support, or when they resulted in coordination among different levels of government.Creating more regional networks can help launch climate adaptation and resilience planning initiatives and result in more cohesive planning documents.
There is no one-size-fits-all approach to equity and justice in climate adaptation and resilience planning, but decision-makers and planners play an important role in intentionally designing new policies.For legacy cities, it was helpful to frame climate responses within other city interests to make it more palatable than as a stand-alone topic, and this strategy may help other cities gain traction for their efforts (Hughes 2020).Legacy cities also tended to talk about equity and justice more than other, strong market cities, suggesting that they have found the balance between equitable futures and some amount of economic growth (Mullenbach and Wilhelm Stanis 2022).Regardless of what a city's plan focuses on, if there is to be any movement on equity and justice, it is crucial that cities consider how they will implement their plans moving forward instead of bending towards neoliberal policy solutions, particularly those that rely on outside funding (Fainstein 2018).

Discussion
In this scoping review we sought the state of knowledge on equitable climate adaptation in U.S. cities.We assessed the authors' theoretical frameworks, the methods used by the authors, the content of the plans, the solutions provided by cities, and compiled best practices suggested by the authors.Our findings have implications for both academics as well as policymakers and decision-makers working on climate issues, and our discussion is separated into topics relevant for each of these groups.

Implications for policy and decision-makers
There are several implications of this research.First, most of the work highlighted in this study is examining the contents of different adaptation plans.This is an important step in the process of understanding equitable climate responses but does not tell us what will actually happen when a plan is implemented or how implementation will impact equity and justice.A plan can have the best intentions but be flawed during implementation due to funding constraints or changing political wills within a city.Codifying and requiring climate action is also critical, as cities will be required to adapt if a plan is made law, even in changing political environments.
As for the content of city plans, distributive justice tended to get the most attention (Fiack et al 2021).It is critical that residents have equitable access to adaptation and resilience amenities and that environmental harms are distributed fairly.It is a positive sign that plans recognize and emphasize this.However, the lack of procedural and recognition justice elements in climate plans raises the question of how just plans are in the first place.If the planning processes are not inclusive and certain voices are left out when plans are developed, this is likely to perpetuate existing inequities across cities when it comes time to implement.
On a larger scale, regulations-such as limits or constraints on developers, extractive land uses, energy consumption, etc.-have the potential to fundamentally change the way that cities operate and whose interests they are operating for (Meerow andWoodruff 2020, Shi 2021).Allowing unchecked development may seem like an economically beneficial decision to a city but can have real ramifications for residents if gentrification occurs.This exacerbates gaps between those who have access to resilient, climate-ready infrastructure and housing and those who do not, also known as climate gentrification (Gould and Lewis 2021).Requiring (or incentivizing) developers to build affordable housing makes it easier for all types of residents to live in safe, climate-prepared communities (Wetzstein 2017, Webster and Bogunovich 2021).Additionally, regulation of the private sector changes which voices have the most control over climate adaptation but also city decisions more generally.In curbing private sector influence, cities can become more democratic and equitable spaces where residents are able to inform decision-making and have control over what their communities look like (Harvey 2007b, Castree 2008, Knuth 2016).

Implications for researchers
As described in the results, there is some variety in the theoretical frameworks used to assess climate adaptation plans, though these frameworks are similar to EJ theory and each approach has its own advantage.Studies that used the EJ framework described how climate change and responses to it will impact the most vulnerable residents through the ways plans are created and how they are implemented.Neoliberalism papers explained how the approach that cities use-economic growth-impacts vulnerable residents.Finally, just sustainabilities articulated ways that cities could pay more attention to systemic racism.In the future, successful research on climate responses should consider all of these elements.
Future research could also investigate how to increase procedural justice beyond the typical community engagement strategies planners use, such as town halls or public meetings; this work could assess what cities have done to bring their residents into the planning process to make meaningful change.
While it is important to acknowledge the limitations of a theory and continue to expand the ways in which climate responses are studied, the proliferation of EJ-adjacent theories also makes it difficult to keep track of scholarship and research on the topic.It is also difficult to compare progress in climate responses and what various studies find about plan contents when researchers use different language to describe how they are undertaking their analyses.Using the same frameworks also makes it easier to compare plans across studies.Furthermore, the process of compiling findings into best practices or suggestions for adaptation and resilience can be facilitated by using the same language within studies.Doing so makes it easier for scholars to find similar research on the topic and for practitioners to access scholarship on climate responses, without having to sift through different framings and theories.
Another major implication relates to city size.The studies included here overwhelmingly looked at the largest cities in the United States, justifying this by saying they include the majority of the U.S. urban population.While true, there is also a sizeable portion of the country that lives in small-to-medium-sized cities (US Census Bureau 2023).This often includes legacy cities and other places that may not be major players on the international scale, but where climate adaptation and resilience planning could have a serious impact on residents' lives (Ganning and Tighe 2021).Failing to include plans from smaller places in analyses of equity and justice considerations is itself an injustice-one which ignores urban residents in smaller places at the expense of the largest cities in the country.If scholars are to argue that there is no onesize-fits-all approach for climate responses, then it is critical to also study smaller cities to understand how adaptation manifests in those places as well.Perhaps the largest cities could even learn from the smaller ones.Additional scholarship in this area is thus sorely needed.

Limitations
Although this work was meant to synthesize the research conducted by scholars on equitable climate adaptation planning in the U.S., our findings ended up revealing several important implications for practitioners that we highlight throughout our paper.However, we must acknowledge that our interpretation of the cities mentioned in our paper and their various climate responses are filtered through the lens of the researchers who conducted the studies we analyzed.Thus, we are one step removed from the original plans.As such, our findings should be taken with that caveat.

Conclusions for practitioners
If cities were to follow through on the best practices described previously, outcomes for vulnerable residents are likely to be more equitable, just, and inclusive.Developing clear implementation guidelines within climate adaptation plans increases the likelihood of plans being implemented in the first place, particularly if specific government agencies are held accountable (Malloy andAshcraft 2020, Chu andCannon 2021).Pairing implementation with investment in frontline communities and working with community-based organizations further increases the likelihood that adaptation will work towards reducing inequities (McNamara and Buggy 2017).In particular, community organizations could help cities and planning departments tailor strategies to the needs of their communities, further increasing equity and justice (Fainstein 2018, Rudge 2021).If done regionally, adaptation actions could be coordinated across multiple agencies, groups, and organizations, ensuring that the largest number of people possible benefit from new programs and opportunities surrounding adaptation and resilience (Shi 2019).However, as we mentioned, legacy cities may need to adopt different strategies to overcome their unique vulnerabilities and challenges; it is out of the scope of the present study to postulate such solutions, though smaller, and legacy, cities face different challenges that may require different solutions.

Conclusions for researchers
Overall, research on planning for climate change is progressing rapidly and has implications for our understanding of equitable climate adaptation.Recent work has investigated how the different dimensions of EJ are included in adaptation plans and how this will impact residents.Others have researched legacy cities' adaptation plans specifically, to see how these cities compare to others across the country in terms of equity and justice.Even more research has looked into the influence of neoliberalism on adaptation planning, which actors are involved in the planning process, and how they influence decisions.However, the best research may consider including elements of all three frameworks.The EJ framework lacks underlying systemic explanations for conditions, in the way that neoliberalism does; and just sustainabilities offers a connection to the environment and pursuit of sustainability in addition to social justice; thus, including perspectives from all three of these frameworks would yield a holistic understanding of climate adaptation planning.Lastly, study scale ranged from regional to the ten largest U.S. cities-though relatively few studies purposefully sought out small-to-midsized cities. Research on this topic should be sure to include a range of climate regions and city sizes.Overall, our synthesis reveals high research activity on equitable climate adaptation, but little variation in theoretical frameworks, methods, and findings.We recommend research continue but to expand in the ways of theory, methods, and scope of inquiry.

Figure 1 .
Figure 1.The figure format has been adapted from Moher et al's (2009) guidelines for reporting systematic review results.* Filters applied to database searches include: full-text, peer-reviewed, scholarly journals, English, published after 1st January 2013.* * Inclusion criteria considered whether an article was empirical research that addressed equity and justice in climate adaptation in U.S. cities.Final refinement step removed articles which were conceptual rather than empirical.

Figure 2 .
Figure 2. Number of studies each city was included in and their climate regions (from National Centers for Environmental Information).

Table 1 .
(Meerow et al 2019)ghes 2020t al 2021)ticle title, and journal name for papers included in this review.Papers marked with an asterisk did not list the specific cities they investigated.examples of distributive, procedural, and recognitional justice(Juhola et al 2022).3.1.3.Characteristics of cities studied in included papersIn terms of the scale of analysis, most of the studies in this review focused on the U.S. cities with the largest populations, to varying degrees (figure2).Two of the studies included plans from the 100 largest U.S. cities(Schrock et al 2015, Fiack et al 2021), and one included the 50 largest(Hess and McKane 2021).These studies selected the 100 or 50 largest U.S. cities, regardless of if the city had developed an adaptation plan, then determined which cities had plans.From that subset, the authors analyzed half of the available plans.Of the remaining studies, one analyzed the 25 largest cities(Cannon et al 2023), and one the 10 largest cities(Chu and Cannon 2021).Mullenbach and Wilhelm Stanis (2022) included plans from 88 cities across the country, both legacy cities and strong market cities.Other studies conducted case studies of different cities(Fainstein 2018, Hughes 2020, Rudge  2021)or regions (Shi 2019) across the country to holistically assess their planning efforts.Additionally, one study analyzed the first ten plans from the Rockefeller Foundation's 100 Resilient Cities program(Meerow et al 2019).
(Hughes 2020rveyed community-based organizations to understand how they participated in the planning process and what barriers to their participation existed (Rudge 2021).Another paper included interviews with planning officials in two cities alongside analysis of those cities' adaptation plans(Hughes 2020).Finally, one paper developed an adaptation justice index by reviewing articles in the literature that provide

Table 2 .
Climate adaptation best practices and descriptions.