Geographic Distribution and Study Methods in City Climate Action Research

Distribution of Research and Study Methods

The focus on city climate action varies significantly across global regions. A comprehensive review of 103 articles reveals that European and North American cities are the most studied, capturing 36% and 34% of research, respectively (Table S4). Studies concerning Asia account for 14%, while Latin America, the Caribbean, and Africa each represent 7%, and Oceania a mere 3%. These studies span 108 countries, predominantly from OECD members (75%). Research often concentrates on cities in a single nation or region (73%), with fewer studies covering multiple regions (18%) or having a global perspective (8%).

Research methodologies exhibit diversity, with 55% of studies relying solely on qualitative methods, 17% on quantitative methods, and 27% employing a mix. Qualitative studies often utilize primary data (58%), whereas quantitative studies favor secondary data (67%). Mixed methods studies generally integrate both data types (61%). Qualitative analyses frequently involve document analysis (51%), while quantitative studies predominantly use regression analysis (79%). Mixed methods approaches uniquely blend techniques for comprehensive insights. These methodological variations correlate with geographic focus, with qualitative and mixed methods prevalent everywhere except Oceania. Quantitative-only studies are more common in North America, Europe, and global assessments, with limited focus on Asia.

Determinants of City Climate Action

Our analysis identified 551 instances of factors linked to climate action from 103 articles, categorized by a predefined taxonomy (Table S3). Beyond the 90 taxonomy factors, seven unique elements emerged, including social capital and COVID-19 impacts. Since 2016, the recognition of government capacity as a factor surged.

Bars indicate the number of times a factor was identified.

Government capacity emerged as the most frequently cited factor (34%), followed by government interests (16%) and intergovernmental factors (14%). Community support (11%) and government structure (9%) were less common. The least cited were built environment (2%) and environmental factors (6%). Some studies highlighted interactions, such as external funding and local leadership driving climate action.

Within categories, identification varied. For instance, government capacity and interests had numerous identified factors, while environmental factors and city structure had fewer. Regional gaps exist, particularly in diversity-related aspects within city structure.

At the individual factor level, 15 out of 90 factors accounted for 63% of identifications, with staff capacity and stakeholder involvement leading. Many factors were rarely identified, underscoring gaps in research focus.

Geographic Influence on Climate Action Factors

Regional variations in factor identification are evident. All factor categories were noted in Europe, North America, Asia, and Oceania. Africa and Latin America lacked certain categories like built environment. Similarly, global studies often overlooked government structure and community support.

Europe accounted for 38% of individual factor identifications, followed by North America (32%). Asia, Latin America, and Africa had fewer identifications. While the most identified factors were similar across the global North and South, regional distinctions were notable.

Circles sizes reflect the number of times a factor was identified. Factors shown are those with the greatest absolute count in a region. When more than one factor had the same count in a region, the factor with the higher regional concentration ratio is shown, calculated as Regional concentration ratio = [(count for factor in that region) / (total count of all factors in that region)] / (count for factor overall / count for all factors overall).

While North America and Europe shared key factors like policy frameworks, Latin America focused on administrative structure. In Africa, technical capacity was significant, reflecting regional priorities.

Association Consistency and Direction

Among the 551 factor instances, 61% showed a positive association with climate action, while 34% were negative. Consistent associations appeared for city network membership and political attitudes. Regional consistency was noted for factors like intergovernmental relationships and public issue salience.

Strength of Factor Associations

While many studies didn’t specify association strength, frequently identified factors often had strong links to climate action. Fiscal capacity and city networks were particularly influential. Some less frequently noted factors, like coastal proximity, also showed strong associations.

Regional consistency in strong associations was found for fiscal and technical capacities. However, data gaps remain, especially in Oceania and global studies.

Circles sizes reflect the number of times a factor was identified. Factors shown are those with the greatest overall strength of association in a region, calculated as Strength of association = [very strong + strong] – [weak + very weak]. All factors shown have strong association overall except the three factors in Oceania, for which strength of association is weak.

Regional gaps, especially in Oceania, limit definitive conclusions. In global studies, city networks and economic structure were strongly associated with climate action.

Comparative Analysis of Factor Frequency and Strength

There is a general overlap between frequently identified factors and strong regional associations, yet exceptions and gaps exist. While North American and European factors often align with strong associations, regions like Oceania show limited data on strength. No clear North-South divide was found, though technical capacity and network membership varied in identification frequency.