The COVID-19 pandemic significantly impacted urban life and highlighted the critical role of urban green spaces (UGS) in maintaining urban resilience and human well-being. Previous research showed conflicting evidence regarding the changes in UGS use during lockdowns, making it crucial to assess these changes globally, considering factors such as COVID-19 policies, economic conditions (represented by GDP per capita), and different types of UGS. Unequal distribution of UGS within and between cities, particularly between the Global North and South, raises concerns about environmental equity. The growing global urban population adds to the pressure on UGS, making it essential to understand the demand for different UGS types during crises to improve urban green infrastructure planning and preparedness for future challenges. This study aimed to address the knowledge gap by systematically reviewing global evidence on changes in UGS use during different phases of the COVID-19 pandemic, categorized by major UGS types and global regions, and analyzed their relation to COVID-19 policy stringency, GDP per capita, and equity aspects.

Numerous local studies on UGS use during the COVID-19 pandemic reported varying changes, some showing decreases during lockdowns due to restrictions, while others showed increases, either during or after lockdowns, potentially due to a compensation effect for restricted indoor activities. However, there was a lack of consensus on whether these changes were consistent across different world regions, user groups, and types of UGS. Previous reviews were limited in their scope and evidence base. This review aimed to provide a comprehensive understanding of UGS use during the pandemic, considering its relation to COVID-19 policy stringency, economic conditions, regional variations, and equity aspects, addressing the limitations of previous work.

This systematic review followed the Collaboration for Environmental Evidence (CEE) guidelines and PRISMA reporting standards. A pre-published protocol guided the study. The search encompassed five languages (Chinese, English, French, German, and Spanish) across multiple databases (Web of Science, Scopus, CNKI, Web of Science Chinese) and Google Scholar. The search string combined keywords related to urban areas, green space types, COVID-19, and UGS use. Initially, 3,310 articles were screened; 177 articles met the inclusion criteria after a two-stage screening process (title/abstract and full text) and critical appraisal for internal validity (using a six-point Likert scale). Data from 237 cities across 60 countries were extracted. Data analysis involved mapping UGS use changes, logistic regressions to assess the influence of COVID-19 policy stringency and GDP per capita on UGS use changes, and chi-squared tests to compare changes across different UGS types. Qualitative data analysis explored equity issues and adaptation strategies related to UGS use. Sensitivity analyses were conducted on high-validity studies. R software was used for statistical analyses and visualizations.

The study revealed significant global variation in changes in UGS use during the COVID-19 pandemic. During the first lockdowns, 60% of locations reported decreased UGS use, while 37% reported increased use. After the first lockdowns, the trend shifted: 34% reported decreased use, and 57% reported increased use. Regions with higher GDP per capita tended to experience increased UGS use, while those with lower GDP per capita showed more decreases. Stricter COVID-19 policies were associated with decreased UGS use, although this relationship was less consistent in high-validity studies. Different UGS types showed distinct patterns: private gardens, UGS near homes, forests, and natural areas predominantly showed increased use, whereas public parks experienced more decreases. Qualitative analysis highlighted equity issues, with low-income groups and socially vulnerable populations facing greater barriers to accessing UGS. Adaptation strategies included changes in visit frequency, duration, timing, group size, activities, and travel distance. Studies using different methodologies (social media and GPS tracking) reported even higher increases in UGS use in some locations.

The findings indicate a strong correlation between economic wealth (GDP per capita) and increased UGS use during the pandemic. Regions with higher GDP likely had better-resourced UGS, allowing them to better meet the increased demand during lockdowns. Conversely, regions with lower GDP may have lacked sufficient or well-maintained UGS, potentially exacerbating challenges for their populations. COVID-19 policies directly affected UGS use, but other factors, including UGS availability and accessibility, and adaptation strategies, also played a significant role. The contrasting trends across different UGS types suggest that diverse green infrastructure provision is crucial for urban resilience. The North-South divide in UGS use highlights existing inequalities and the need for equitable access to green spaces.

The COVID-19 pandemic underscored the importance of UGS for urban resilience and highlighted global disparities in access and use. The findings suggest that increasing the provision of small-scale gardens, utilizing informal UGS near housing, and preserving natural areas are crucial for creating healthier, more resilient, and equitable cities. Future research should focus on long-term impacts of the pandemic on UGS use and the development of sustainable and equitable green infrastructure planning strategies.

The review's findings are based on available literature, which may exhibit publication bias and uneven geographic coverage, with fewer studies from the Global South. The varying methodologies and data quality across studies presented challenges for meta-analysis and quantitative comparisons. Many studies relied on data with strong limitations (Google mobility reports), leading to results differing from those based on other methods. The study's analysis concluded at a point when the COVID-19 pandemic was not yet over; the long-term impacts on UGS use remain unclear.