To answer these research questions, we conducted a deductive qualitative and comparative analysis utilizing a methodological framework originally developed by Hoover et al., 2021 that focused on incorporating environmental justice into the siting criteria for GI. We do not use the coding framework to ask the same questions, but instead use the framework to conduct a comparative analysis of key resiliency/sustainability planning documents from the EU, UN, and two US cities: Portland, OR and Atlanta, GA. The objective of this research is to better understand what resiliency concepts are factored into definitions, planning, and production of urban resiliency and GI development strategies. This study will be referring only to the findings for these two selected cities, and not generalizing beyond that. When this study references findings for ‘cities’ or ‘US cities’, this is being used to mean specifically the included cities of Portland, OR and Atlanta, GA. Supplementary Table S1 lists the selected documents used in the comparative analysis, and shows the affiliations for each of those documents.

GI benefits are often explained using terms like ecosystem services, which is also a term that lacks clarity and understanding across silos of language (Spirn, 1984). This study uses a definition of ecosystem services developed by the United Nations (2010) that groups those services into four categories. These categories are 1) provisioning services or the provision of food, fresh water, fuel, fiber, and other goods, 2) regulating services such as climate, water, disease, and pollination, 3) Soil formation and nutrient cycling, and 4) educational, aesthetic, and cultural heritage values. By developing sub categorical and categorical groupings that include the definitions of words like resiliency, GI, and ecosystem services, this research allowed basic comparative analysis of city resiliency plans and international guidelines to see if different groups working on projects from different scales and perspectives are still attempting to address the same issues.

Economic criteria are defined as criteria related to urban resiliency based on budget, cost, benefit-cost analysis, or opportunities for land or business development. This appeared to be the most important category for international documents pertaining to resiliency, but was clearly prioritized less with half as much focus being placed on this at the city level. Examples where this was a higher priority at the international level was direct policy for poverty and workers rights issues. This aligns with existing literature that emphasizes the importance of economic considerations in resiliency planning, and suggests that long-term economic implications of policies are left to international groups while operational tasks are left to smaller scales such as cities (Andersson, 2014). This finding does keep with literature regarding the importance of economic considerations when engaging with resiliency planning, and with Andersson, 2014 description of strategical consideration of long term economic implications of policy being left to international groups and operational tasks left to a smaller scale like cities.

The economic criteria group included subcategories of cost, economic development, land development, and general economic planning. Cost is defined within this study as the estimation of the price of completion, cost/benefit analysis, opportunity cost. Examples of cost could be found within each of the comprehensive plans, including each of the types of cost being evident at both the international and city scales. Economic development is defined as improving economic wellbeing and quality of life through the creation of wealth. Land development was defined as improving their physical environments to appropriately fit their needs. When normalized for the varying scale in document length, the data shows that the EU and UN documents focused on economic development as a key component of that resiliency (51.02%) (Figure 2). In Atlanta and Portland, economic considerations focus much more on experiential impacts (e.g., the opportunity cost of development on human experiences within their communities), the cost of resiliency in economic terms, and changing urban landscapes to better suit the needs and expectations of community members (City of Atlanta, 2017; City of Atlanta, 2021). Based on our research, cost was the most important economic criteria to the City of Atlanta (30.84%). Compared to international SDGs, city plans coupled land development much more with economic development. As an example of this from the materials, consider the Global Indicator Framework Goal 1: Ending poverty in all its forms everywhere. While this is concerning economic development, it does not couple with land development in the same way that examples from both US cities do, through land and community revitalization (3:1 p 1 in Global Indicator Framework after 2022;"22:311 p 129 in ATL Plan A Comprehensive Development Plan).

Cost playing the key role at the city level was evident throughout the materials, as each policy was usually accompanied by figures for economic cost/savings, or economic benefits with the land projects being proposed. Most projects are an attempt to improve communities to make them more resilient to economic or environmental shocks through economic investment and intentional land development practices. Cost played a more prominent role at the city level because more actionable projects at the site level were included in these documents, forcing a discussion of costs, cost/benefit analysis, and opportunity costs to be mentioned at a higher level. Attention at the international level was more focused on broader economic strategies that would provide these same resiliencies at a larger scale. International and city policies both tended to look to areas where resiliency issues were already existing, attempting to resolve trouble spots at their scale as they deemed priority. Eradicating poverty, while not a part of the city resiliency strategy, is still prioritized through the elevation and coupling of economic and land development (City of Atlanta, 2021; Shandas, 2010).

Logistics is defined as criteria related to urban resiliency based on physical observations, spatial constraints, professional expertise, and consideration of implementation processes. Essentially, it is the category tasked with the question of how each of these policies within a comprehensive plan will be implemented and maintained. The logistics of resiliency planning is wide-ranging in scale and are often job dependent. For example, considerations of how to promote tourism that in turn creates jobs and promotes local culture and products was labeled logistics. Something much more physical like building and maintaining resilient infrastructure can also be found under general logistical categories. Our findings were that international resiliency plans considered logistics and the coordination of plans slightly more than cities, but that for both scales logistics was nearly equally important.

Subcategories included feasibility, field observations, leveraged opportunities, ownership, scale, and transitional planning. Logistics is rated as the second highest category for international SDGs (24.46%) and for US cities when averaged (19.79%). While international documents focused heavily on feasibility and leveraged opportunities, US cities were more likely to consider how to improve properties already under their control, and to find ways of monitoring and maintaining ongoing projects. Feasibility is defined by the degree of ease a task can be completed, can include spatial and financial. A great deal of the feasibility examples for international documents were related to the financial and resource investment in key infrastructure in impoverished nations of the international community (3:8 p 2 in Global Indicator Framework, 2022). Similar facilitation concerns were seen at the city level as well, but scale of projects were usually focused to areas that have been neglected or victims of past environmental or economic injustices. These questions of facilitating resiliency through the moving of resources to areas in need seems to be a similarity across scales.

Leveraged opportunities, defined as the ability to influence action or the completion of specific tasks through policy, incentivization, or relationship building, are seen at both the city and international scale. These often look drastically different though in both policy and practice dependent upon scale (Andersson, 2014). As an example of this, the city of Atlanta is leveraging relationships within the community and planning experts to develop future land use (FLU) maps along with Character Area Planning to help guide the future growth and development in future years (City of Atlanta, 2021). This leveraging of opportunities was used in similar ways to find positive outcomes at the international level. Leveraged opportunities at the international scale were often to help benefit high cost or risk projects. This is also an area where injustices are attempted to be righted at the international scale, like with issues of the empowerment of women (3.28 p 7, Global Indicator Framework, 2022) energy efficiency (3.39 p 8, Global Indicator Framework, 2022), and economic productivity (3.43 p 9, Global Indicator Framework, 2022). This versatility and ability to have direct impacts on deliverables makes leveraged opportunities an important subcategory of the logistics criteria.

City documents made more linkages to the scale and contextualization of projects within the system that they were nesting within. For example, many of the ecological projects listed by the City of Atlanta were contextualized between the community they impact and the larger watershed. This type of contextualization of scale is lacking from the international documents, where instead the focus is on broader logistical issues and providing resiliency strategies across all borders. International documents tended to focus more attention on how to resolve existing global issues like poverty, access to resources like potable water, and the development of education systems that may lack curriculum on resiliency and sustainability practices.

Social is defined as criteria related to urban resiliency based on resident or neighborhood engagement or involvement, increasing access to green space for cultural or social benefits, resident health, educational opportunities, or environmental justice or equity. The social criteria of resiliency planning can be broad in scale but deal with community building, human interaction, and the human experience within the environment. Important subcategories within social were education, health and wellness, community, and public outreach. Many of these saw key differences at the sub categorical level.

The social category ranked as the highest overall priority for cities (29.89%). Social criteria also had the highest number of subcategories (11). These included community, education, access to green open spaces, heat exposure, health and wellbeing, livability, public outreach, recreation, safety, visibility and general social concern. While international documents maintained a relatively high level of attention spent on social issues (20.11%), the primary focus within the subcategories is general societal concerns, many of which were not as imperative when viewed from the perspective of cities. As an example of this, there are Global Indicator Framework goals that strive to “broaden and strengthen the participation of developing countries in the institutions of “broaden(ing) and strengthen(ing) the participation of developing countries in the institutions of global governance… 16.8.1 …voting rights of developing countries in international organizations"(3:119 p 20, Global Indicator Framework, 2022). These types of general societal issues are not as visible at the city level, which had a clearer focus on community, education, and public outreach.

The Community subcategory includes concepts related to urban resiliency development with the intention of the improvement of culture, access to public engagement, and the building of an overall sense of unique community, often confined to the neighborhood level. By definition, development of community happens at smaller scales (Hanley et al., 2007). International documents attempt to develop this sense of community through a foundation of economic and social security instead of direct community development and public outreach. For example, the city of Atlanta focuses on designing so that “(new) urban growth creates a dynamic environment for everyone (22.43 p 31, Plan A)”, with future land use designations designed specifically to improve different aspects of the social criteria: public schools (education), fire stations and police precincts (safety), health centers (health and wellbeing), senior centers and water plants (livability) (22.57 p 40, Plan A). This shows not only why social was the most important category for cities, but also how the resiliency of our urban environments is reliant upon the resiliency of the people that live within them.

(Curry-Stevens et al., 2011) Cities are focused on improving upon existing benefits of living in urban environments, specifically to improve health, education, and job opportunity. With the social category having the highest overall percentage of overall coding (29.89%), higher levels of focus within these subcategories can be expected. For cities, resilient solutions included building sustainable communities (18.275%) that provide health and wellbeing (14.75%) through public outreach (13.12%). These overlaps show the holistic approach to many of the policies and programs that were resiliency based, especially those dealing directly with communities. Figure 3 illustrates how each of the subcategories are divided between both cities and the international documents. This provides a better understanding of how social criteria is broken down, and which subcategories see differentiation from international ones. Cities seem to be better equipped to handle the details of this type of resiliency planning, while at the international level documents tend to focus on broader social dynamics described above.

There is considerable overlap within subcategories between health and well-being and heat exposure, meaning that when something was coded for one it was often paired with the other. This shows that there is already a firm understanding that higher heat exposure can lead to risk to health and wellbeing. This overlap is similar to the one found between health and wellbeing and recreation, with understanding that focusing on one can have tertiary benefits that improve other environmental criteria. A another similar overlap is found between air quality, transportation, and health and wellbeing at the city level. Many projects and policies are proposed with the improvement of overall livability in the urban environment as the goal. Livability is defined as the frame conditions of a decent life for all inhabitants of cities, regions, and communities. This includes both physical and mental wellbeing. While citing air or water quality improvement improvements, tertiary benefits to the health and wellbeing of those impacted by the project, and comes into consideration when determining cost/benefit analysis. When packaged for policy delivery, this arrives in a form that speaks to improvement of livability, health, and community at the city level (22.65 p 48, ATL Plan A, 2021).

Access to green open space was highly cross-coded for similar reasons. Most projects or policies were not directly designed with the specific purpose of providing green open spaces. They were instead designed to improve neglected neighborhoods or watersheds (24.85 p 47, Central City 2035, 2020), repurposing land use for conservation (22.65 p 26, ATL Plan A, 2021) or for revitalization and recreation (22.35 p 26, ATL Plan A, 2021). While some of these plans do directly point to the benefits of equity of access to green open spaces, these are often projects at the city level and are cross-coded heavily with environmental justice.

Environmental criteria is defined as criteria related to urban resiliency planning based on non-hydrologic environmental priorities or concerns such as increasing resiliency or improving air quality. The environmental consideration within resiliency criteria were similar between international documents and those documents evaluated at the city level. Not only was there this similarity between scales (city-to-international comparison) but within scale (city-to-city comparison) the prioritization of environmental criteria is clearly important.

Environmental criteria played a major role for cities and international documents, with many of the cross-codes occurring within the same category (environmental). This speaks to the connectedness of the topic of resiliency to our relationship with the environment that we are living within. An understanding that to have resiliency, we must sustain and improve our relationship with the land that we are living on and the resources we consume to do so. Response to climate change is defined as references within urban resiliency plans to the long-term shifts in temperature and expected weather patterns for communities. While international plans can think of this response in terms of mitigating loss of life in major natural disasters, cities are being tasked with determining these changes in risk and adjusting their resiliency strategies accordingly. Both cities that were included in this study have comprehensive climate action plans. As an example, the City of Portland includes consideration of changes in precipitation patterns affecting streamflow and groundwater, recharge, and flooding, increases in risks of wildfire, drought invasive plant and animal species, and fish and wildlife populations (32.33 p. 13, Climate Action Plan, 2020). Each plan has extensive cross-coding with subcategories like public outreach (32.20 p 10, Climate Action Plan, 2020) to show the benefits to involved groups, usually developed at the watershed level.

The subcategories focusing on environmental justice (17.33%) and ecological habitat (19.45%) provided for interesting findings from the city-to-city comparison. Environmental justice is defined as the addressing of unfair exposure and harm caused through exposure to environmental harms, specifically focusing on policy and practice that impacted marginalized communities with resource extraction, hazardous waste, and inequitable exposure to environmental harms (Sutter, 2018). Soil and air quality were given less attention at the international level. While both soil and air quality are outcomes of many of the actions prescribed throughout international SDGs, there were fewer instances of discussion of these topics compared to US cities.

Hydrological criteria are defined as criteria related to urban resiliency to manage the quality or quantity of stormwater, natural water systems, or water supply. Topics on water resiliency cover a broad scope, although played a much smaller comparative role than other criteria, mentioned less frequently within these comprehensive plans and international recommendations. Some examples of hydrological criteria being found in the international materials is Goal 6 of the Global Indicator Framework being to ensure availability and sustainable management of water and sanitation for all. This is a very different conceptualization from US cities that focused primarily on watershed improvement plans.

The Hydrologic criteria subcategories included: stormwater management, water quality, and water supply availability (see Figure 4). Stormwater management is defined as the process of controlling the runoff that comes primarily from the built environment, such as parking lots, driveways, rooftops, and roadways. An example of stormwater management being included in resiliency planning is the city of Portland making changes to stormwater reservoirs to be able to maintain higher quantities of runoff during major precipitation events. Water quality is defined as the condition of the water, including chemical, physical, and biological characteristics, usually with respect to its suitability for a particular purpose. (BenDor et al., 2018) Water supply availability is defined as the source, means, or process by which water is supplied to the community and can include means such as hard/grey infrastructure required, expertise provided, etc.

Figure 4 provides a visual for the comparison of Hydrologic criteria and subcategories, showing both nuanced differences between cities and more stark differences between scales. When normalized, there is a tendency for cities to be focused on stormwater management at site and regional level, while international documents tend to have more generally focused hydrological concerns, and tended to have more focus on the water supply availability than did the US cities. Water availability and potability seemed to be more important for resiliency at the international level (30.0%). Atlanta and Portland instead focused upon improving or sustaining the water supplies that they have and have had in the past (Chattahoochee River and tributaries for Atlanta and Columbia Rive and tributaries for Portland), as well as designing improvements, and rehabilitation of hydrologic habitats around function and human purpose, as watershed improvement plans established by both cities (22.296 p 124, Plan A, 2021; 32.265 p 132, Climate Action Plan, 2020).

Comparatively, Atlanta and Portland tend not to focus as much attention on the availability of a sustainable water supply, usually touching on water quality when listing project benefits. For example, supply of available potable water for future resiliency concerns is not directly dealt with in any of the included comprehensive plans, at either the international or city level. Water quality is discussed more frequently in context of either hydrological habitat rehabilitation, or recreation (i.e., swimming). As an example of this, Atlanta’s framing of the restoration of riparian habitat bases the benefits of this project in ecosystem health, value of ecological function, and for improvement of recreation. While water quality is acknowledged, it is not the primary objective of the project, and water supply availability benefits are only considered tertiarily.

Transportation is a theme that emerged from both the literature and the findings as still holding importance in considerations of resiliency, particularly for Atlanta and Portland. Discussion regarding transportation in these documents ties to other categories impacted, such as air quality. Examples of this can be found especially in the City of Portland comprehensive central city plan, with improvements in transportation being tied to increases in air quality and decreases in heavy metal pollutants (24.91, p. 50 Central City 2035, 2020). Optimizing street design and efficiency within this plan is linked to improvements in safety, health and wellbeing, and livability. The city of Portland specifically points to improvements in transportation to air quality and livability, including consideration of carbon costs and embedded energy costs of goods and services. Both cities provide more specific guidance regarding traffic and road maintenance plans than can be found at the international level. This is evident through both cities setting goals of “optimizing existing street networks” (Portland) and the development of policies in Atlanta to “maintain and improve accessibility and connectivity for pedestrians, transit riders, cyclists, and in-city and through-city freight traffic” (22.159, p. 83, Plan A, 2021; 14.91, p. 50 Central City 2035, 2020). Both cities studied placed an importance on lowering carbon emissions by providing more efficient means of travel and transport of goods and materials. This improvement extends beyond simply lowering emissions and takes into consideration traffic safety, especially in the city of Atlanta where the Vision Zero Program has established a goal of zero fatalities through the improvement of roadways, speed limits, transit access, and transformation of high-crash corridors to safer pedestrian friendly zones (22.160, p. 85, Plan A, 2021). Issues regarding transportation were less visible at the international level, and most dealt with cross-coded logistical issues like equitable access to travel across borders.

The “Other” criteria includes important subcategories that lacked appropriate categorical definition based on Hoover et al., 2012. Subcategories include exclusions, principles, and transitional. Exclusions is defined as the process by which a specific area or group are excluded from the expectation of urban resiliency planning. Principles is defined as a fundamental truth or proposition that serves as the foundation for a system of belief or behavior or for a chain of reasoning. Examples of principles that influenced resiliency planning from an international perspective are ending malnutrition and violence against women (3.10 p. 2, Global Indicator Framework, 2022; 3.11, p. 2, Global Indicator Framework, 2022). Neither of these principles were mentioned at the city level, although each had their own plans to improve child health and improve economic opportunities for minorities and women. Transitional is defined as currently un- or under-developed land that present an opportunity for providing habitat until such time in the future as economic conditions make them desirable for development. Examples of transitional codes are brownfield or contaminated sites in industrial zones being cleaned and revitalized for future use, and examples of this type are found more often at the city levels. These remain in the other category because of the overarching nature of principles and the choice to exclude either a group or area from the resiliency planning all together. Both are intrinsically having impacts on the rest of the projects and their categories.

Our findings show how differing prioritization or a change in problem framing can impact resiliency planning at different scales. For example, air quality holding a high priority at the city level attributes to higher prioritization of transportation issues such as traffic. Cities see an opportunity to improve upon air quality in a way that also has many tertiary benefits that cross-code with livability and health. Cities planning documents identify transportation issues as being necessary for the continuance of business, but also as providing benefits toward resiliency goals. This is also in line with literature about local scales being responsible for operational undertakings like ensuring that infrastructure is developed and maintained according to the needs of the community (Andersson, 2014). Key differences were also found related to how ecosystems services are defined and incorporated in the documents analyzed. For example, our analysis found that international plans focused more on provisioning and regulating equity and access to improvement of working conditions and services like improved access to healthcare, while city planning documents for Portland and Atlanta focused on cultural services such as community wellbeing, recreation, and development of green open spaces. Figure 5 illustrates how the ecosystem subcategories are referenced in US cities and international planning documents. This figure helps to visualize similarities in importance for policy development regarding ecosystem services and what those policies are actually targeting (Ervin et al., 2012).

Green Infrastructure techniques are often provided as alternatives within project proposals as both cost-saving and environmentally conscious techniques that provide key ecosystem services (Andersson, 2014). The most common use of Green Infrastructure currently involves stormwater management and flood mitigation during high precipitation events (Finewood, 2019; Firehock and Walker 2015). The difference in prioritization of stormwater management between scales suggests that Green Infrastructure is more applicable or appropriate at the city scale, where stormwater management and heat exposure concerns are greater. If Green Infrastructure is to be prioritized at a larger scale, it might be more beneficial if framed in a way to draw upon the benefits provided by the project beyond that of just stormwater management, such as cultural services (aesthetics, recreation) or regulating services (air quality improvements). This may increase the likelihood of adoption at larger scales, and in geographic regions that may not need the same types of GI due to variation in precipitation (Benedict et al., 2012). Our findings suggest that framing the implementation of GI with ecological, community, educational, and livability concerns could increase use at all scales and in different scenarios (Benedict et al., 2012).

We found several instances of where the criteria emphasis between the US cities and international scales were similar, particularly at the category level for Environmental, Logistics, and Social categories. Furthermore, we found similarities within a few subcategories, particularly the hydrological subcategories. While hydrological category may have rated comparatively low as a priority during resiliency planning, the subcategories of water quality and water supply availability were given equal proportions of the resiliency plans at both scales. This finding is also supported with literature regarding GI implementation and management that find that these projects are primarily utilized for stormwater management (Baker, 2019; Benedict et al., 2012; Conway, 2020). If similar national level policies were implemented for heat exposure, for instance, GI usage might increase through the development of more tree canopy, green walls and roofs, and improvements to access to green open spaces.

Resiliency at its core is less dependent upon understanding the exact risks of the future and instead an attempt to tolerate increasing levels of uncertainty and the institution of broader programs to help absorb existing and new stresses that the urban environment might face (Rich, 2014). Our findings reveal that while at the categorical level (e.g., environmental, costs, social) we find many similarities between international and city documents, it is at the sub-categorical level we find more differences due to their geographic research and foci. Based on these findings and the existing literature that it fits into, key features of resiliency planning that are unifying (i.e., health and wellbeing, air quality, education, hydrologic) should be broadly defined for consistency and unity in plans and practice across scales. National scale programs and policies with general guidelines would help smaller scales like cities to be responsible to meet, creating an atmosphere for the creative development of resiliency solutions. These solutions may still be geographically or culturally unique, but still work toward common resiliency goals set at the international level. This is in line with current literature regarding strategies for optimizing resilient planning and large-scale interdependent critical infrastructure (Huang et al., 2018; Afrin et al., 2021).

At the subcategory level of analysis, clearer indicators emerge of distinct differences in focus and intent within categories. Differentiation between scales and gaps in cross-scaling has also been noted in previous research and are reinforced by our findings (Borgström et al., 2006). For example, instances where there are differences found at the sub categorical level (i.e., social, logistics) present opportunities to tailor expectations and definitions of resiliency to their geographic place. For example, the sub-category of “social” shows distinct differences of focus between international and US city scale (Figure 3). Some of these differentiations are occurring due to expectation of role for resiliency planning between scale (strategical v. operational). An example of this is the percentage of social criteria, which is shown as a Sankey graphic in Figure 4. For example, it is imperative that city planning have clear directed goals and policies related to public outreach, whereas the international planning documents may support education and learning opportunities but lack specificity regarding implementation strategies (Nita et al., 2022).

This research uses a deductive coding regime, developed for comparative analysis of urban plans for decision making regarding GI placement and environmental justice. We recognize that many international planning documents were not created specifically for urban environments, or with resiliency implications in mind. Due to methodological and funding limitations of this study, comprehensive determinations regarding resiliency planning at any scale would require additional research. This additional research could be done from the perspective of cities attempting to improve their own resiliency plans and would be more reliable with the inclusion of all applicable materials coming from this perspective in the future. Other previous studies have pointed to similar limitations, and alluded to the need for further focus on network analysis and GI development to better understand the relationships and dynamics of development, implementation, and maintenance of GI projects (Badiu et al., 2019; Borgström et al., 2006).