Perspective
Environmental health Global health
Volume 222 - Issue 3

Urban green space provision: the case for policy‐based solutions to support human health

Authors:  Craig Williams, Christie Byrne, Shannon Evenden, Veronica Soebarto, Stefan Caddy‐Retalic, Carmel Williams, Yonatal Tefera, Xiaoqi Feng and Andrew Lowe

Med J Aust 2025 || doi: 10.5694/mja2.52569
Published online: 20 January 2025

Urban green spaces are dynamic contributors to the wellbeing of our cities, offering benefits to the health of humans, society, and natural and managed ecosystems

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As one of the world's most urbanised nations, Australia1 is particularly vulnerable to diseases causally linked with urban living.2 Further urban growth requires systemic health policy solutions. Urban green spaces (UGS) are dynamic contributors to the wellbeing of our cities, offering benefits to the health of humans, society, and natural and managed ecosystems. Here we define UGS to encompass planned and intentional green spaces such as parks, curated gardens, sports and recreation areas as well as urban forests and nature reserves, and unconventional green zones such as easements, road and infrastructure routes, streetscapes and commercial precincts.

Increasing urban infill and expansion of housing across Australian major cities is placing greater pressure on green assets as both places of recreation and refuge for communities.3 The expansion of essential grey infrastructure is important for ensuring equity of access to services and facilities for all residents but, nevertheless, increases pressure on UGS.

Here we explain the public health benefits of UGS. We identify barriers to the provision of sufficient, equitable UGS and describe the disconnect between the resourcing required to achieve this and the health and productivity gains resulting from it. In doing this, we make a case for policy‐based solutions.

The health benefits of urban green spaces

Exposure to UGS has a powerful impact on physical and mental health and overall social wellbeing, with concomitant benefits also for the health sector in terms of reduced burden and significant cost savings.4 It achieves these health benefits through interlinked adaptive pathways.5

UGS can provide spaces to enjoy and engage in sports and recreation and can encourage active transport use such as cycling and walking.6 It provides amenity through shading, cooling and exposure to the benefits of biodiversity and the mitigation of air pollution and noise, all which contribute to positive health impacts.7 Australian studies have demonstrated that people residing within 1.4km of large, attractive green spaces were more likely to engage in recreational walking and meet the minimum physical activity guideline than those who lived further from such spaces.8 Green space, particularly tree canopy, has also been associated with reduced rates of morbidity from cardiometabolic diseases, lower psychological distress, and lower risks of dementia diagnosis.9,10,11,12 Emerging research also indicates that natural spaces support biodiverse and healthy soil, which shape the human microbiome, and promote immune fitness.13 Access to green space has also been linked to reduction in crime14 and increased social cohesion and social capital.15,16

Evidence of the positive mental health effects of UGS continues to build.17 Green space provides places for social interaction and facilitates community connections and wellbeing. This is important for feelings of safety, neighbourhood satisfaction and positive mental health, and can help to reduce social isolation.18 The dose of UGS experienced by people is also important, with an exposure of at least 30 minutes per week lowering rates of depression and anxiety, reducing stress levels, and enhancing mood.19,20 Further, spending two hours or more per week in natural environments is associated with higher levels of self‐reported good health and wellbeing.21

Increased urban greening facilitates resilience to heat by providing shade and evaporative cooling. Australia's air temperature is predicted to increase in the range of 0.6–2.5°C by 2050 (relative to 1995–201422). In addition, higher urbanisation and densification are increasing the proportion of the population exposed to urban heat island effects. Mitigating these effects through urban greening is an essential requirement for vouchsafing human health. A study in Adelaide, South Australia, found that urban greening can provide up to 2°C cooler urban climates.23

Importantly, these benefits are not experienced by everyone in the same way. The psychologically restorative benefits of nature contact are dependent on the severity of cognitively stressful demands felt — more need entails greater potential for benefit.5,24 This is seen in the mental health of adolescents who tend to be more introverted or prone to chronic rumination benefiting disproportionately more from access to green spaces, in comparison to their more extraverted and contented peers.12

External factors might also constrain levels of health benefit beyond the issue of accessibility, with recent evidence indicating that residents of apartments are constrained to do regular exercise outdoors due to small and overcrowded nearby green space and are thus more likely to experience a major cardiovascular event compared with people who live in houses.25

The urban green space deficit and the unknown quality standards

Increasing recognition of the value of UGS and its equitable availability to residents has led to the creation of green infrastructure strategies and management plans (eg, City of Melbourne's Green our City26). Others are in development at the time of writing (eg, Urban Greening Strategy for metropolitan Adelaide27). These strategies contain aspirational targets for green space provision through the proportion of canopy coverage and urban heat reduction, but their efficacy in the absence of mandated commitments has yet to be demonstrated.

There are many metrics available for defining green space availability, with most describing accessibility (eg, access to green spaces within a 15‐minute walk) and the per capita green space area (m2) available.28 In this way, defining UGS deficit depends on the metrics chosen, and, in the absence of an internationally agreed standard, it is difficult to resolve.

The scale at which accessibility is measured is also critical, with most cities containing suburbs with greater and lesser access to green space that are masked when accessibility is measured at a municipal or regional scale.29 Beyond quantity‐related metrics, the quality of these green spaces is crucial in maximising their positive impacts on public health.17 There are many ways to measure UGS abundance, accessibility and quality.30

There is inequity in the distribution of green space as well as canopy coverage across Australian cities.28 Inner suburbs (typically with higher land values and household income) had much greater UGS compared with outer suburbs and peri‐urban areas (typically with lower land values and income).28 This pattern represents significant health inequities, which are also recorded in other countries (eg, New Zealand31). There is also variation in UGS between major Australian cities, with Sydney and Brisbane providing more green space area per capita than Melbourne and Adelaide.

Rectifying the inequitable distribution of green space within cities will require changes to the policy development process of governments. Addressing complex public policy issues requires joined up and collaborative approaches to policy development, where the breadth of issues affected by the policy can be considered. These changes to the policy process can be supported with the development of legislation and regulations that embed agreed measures to evaluate existing UGS and their health benefits. Although some countries have such standards (eg, the United Kingdom32), most do not. The application of the “3–30–300 rule” — namely, that all people should be able to see 3 established trees from their home or workplace, have at least 30% tree canopy in their residential neighbourhood, and live within 300m of high quality green space32 — might form the basis for an agreed future standard. This is founded on the consistent association between 30% of tree canopy and better mental, cardiometabolic and cognitive health.4 The absence of a standard creates difficulty in planning and financing UGS provision.

Overcoming barriers to urban green space development

Significant barriers to ensuring equitable UGS distribution to a standard that equates with better health and wellbeing outcomes include:

  • Competing land‐use interests. With population growth and a well documented shortage of housing, green space provision is in conflict with land for housing.
  • Physical barriers. There is limited public space in existing urban areas, and including more might not be possible when combined with grey infrastructure needs. Private green space is being lost through infill development and limited incentives and legal barriers to encourage private landowners to retain established trees.33
  • Restricted financial capacity. UGS development requires financial investment, for which there is limited capacity in local government. This is exacerbated by low levels of community awareness, ecological literacy and engagement34 and limited expertise within government to develop green spaces, particularly if it is perceived as low priority and/or expensive to maintain without an appreciable return.
  • Bureaucratic challenges to democratic decision making and effective collaboration. Weak environmental protection laws are commonly combined with regulations that readily permit tree removal or radical pruning for protecting vital network infrastructure and enable urban development at the expense of UGS.35
  • Lack of urban planning decision support tools and processes that account for the health, environment, and economic benefits of green space. In Australia, there is still a lack of clear frameworks and decision support tools that can assist local governments and decision makers to take into account the health benefits of UGS.20 Without clear frameworks and processes that all relevant stakeholders agree upon, and without easy‐to‐use tools that can assist decision makers to consider all the benefits of green space versus costs of establishment, maintenance and replacement, it will be difficult to realise quality green space.

These barriers highlight the tension points between the need for housing, infrastructure and amenities and the health and societal benefits of UGS. Overcoming such barriers will require new thinking combined with mandated standards to ensure sufficient UGS provision to maintain human health.

Economic studies might prove persuasive in overcoming financial challenges, such as a recent study providing economic valuation for street trees in Greater Adelaide.36 The initial findings indicate the average present value benefit of planting a tree is $11236, compared with an estimated cost of $6980, translating to a benefit–cost ratio of 1.6. Costed benefits include health improvements from reduced risk of heat‐related illness. Including health care cost savings could be a compelling motivation for action, with recent longitudinal evidence from New South Wales indicating that increasing tree canopy from less than 10% to 30% or more reduces the risk of cardiovascular disease‐related hospitalisations, leading to $20 million savings per 100000 adults per year.4

Conclusion: urban greening standards as a health measure using a Health in All Policies approach

We contend that UGS should be a policy imperative for all governments, requiring joined up and multisectoral solutions to overcome sectoral silos. The Health in All Policies approach, supported by the World Health Organization Health in All Policies Four Pillars Model,37 offers evidence‐based guidance for cross‐sector collaboration to achieve positive health outcomes. This model provides a framework for incorporating UGS in the decision making of all government agencies.38 The new Australian Federal Climate and Health Strategy identifies Health in All Policies as one of key objectives for action and this may create the space and opportunity to elevate trees and green space in the political decision‐making process.39 Such an approach would better link the health cost and benefits of green space (principally enjoyed at the state and federal level) with the expenditure for green space creation at the local government and community level.

Moving the UGS for health agenda forwards will require a coordinated approach involving government, lobbyists, researchers and law makers. Clear and evidence‐based UGS standards can be used to set the vision and direction for whole of government policy action and create the opportunity for the legislative reform required. Such standards must include scientifically determined dose–response provisions, along with considerations for equity and accessibility.40 There is already an abundance of evidence about green space exposure dose and health. Only by inclusion of accessibility for economically disadvantaged communities will such standards be effective and avoid the well documented failure of previously applied park standards that lead to underutilised UGS.40 The Health in All Policies approach can support whole government decision making that leads to embedding of UGS standards within legislation and regulation and can include compliance with standards incentivised by new financial instruments, such as the newly developed Nature Repair Market designed to support biodiversity.41

Authors

  • Craig Williams1
  • Christie Byrne1
  • Shannon Evenden2
  • Veronica Soebarto3
  • Stefan Caddy‐Retalic3,4
  • Carmel Williams3
  • Yonatal Tefera3,5
  • Xiaoqi Feng6
  • Andrew Lowe2
  • 1. University of South Australia, Adelaide, SA
  • 2. Environment Institute, University of Adelaide, Adelaide, SA
  • 3. University of Adelaide, Adelaide, SA
  • 4. University of Sydney, Sydney, NSW
  • 5. South Australian Health and Medical Research Institute, Adelaide, SA
  • 6. University of New South Wales, Sydney, NSW

Correspondence: craig.williams@unisa.edu.au

Competing interests

No relevant disclosures.

Acknowledgements

We acknowledge the HEAL (Healthy Environments And Lives) National Research Network, which receives funding from the National Health and Medical Research Council Special Initiative in Human Health and Environmental Change (Grant No. 2008937). Support was also provided by the Environment Institute at the University of Adelaide. The funding source was not involved in the authoring of this work. The work of the Dynamic State Summit (2022) in catalysing this work is acknowledged.

References

Provenance: Not commissioned; externally peer reviewed.

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