Why cities struggle to use nature for climate resilience

Cities everywhere are warming up, flooding more often, and struggling with polluted air as climate change loads more energy into the atmosphere.

Parks, trees, rivers, and ponds could act as quiet defenses, yet many urban areas still fail to tap their full power.

An international review from the University of Surrey (UoS) was designed to explore why city nature projects so often stall.

By analyzing hundreds of studies and expert reports, the researchers uncovered the often-overlooked hurdles that stand between ambitious plans and on-the-ground action in cities.

Nature-based climate solutions

The analysis was led by Professor Prashant Kumar, founding director of the Global Centre for Clean Air Research at UoS.

Professor Kumar’s research focuses on nature-based solutions (NbS) – projects that use living systems to reduce hazards like heat, flooding, and dirty air.

In this field, a core idea is green-blue infrastructure – networks of plants and water that are woven into streets, roofs, and shorelines.

Recent studies show that such networks can cool neighborhoods, slow floods, clean air, and support wildlife.

Finding what works and what doesn’t

From more than 500 detailed studies and expert input, the team grouped the main obstacles into environmental, social, economic, and governance or policy categories.

The researchers noted that unless cities tackle several of these categories at once, nature-based projects can falter or even backfire after construction.

“The work brings together environmental and social scientists, engineers, economists, urban planners and stakeholders to map 21 underexplored barriers to the implementation of nature-based solutions in the real world, across environmental, social, economic, governance and policy domains,” said Dr. Maria Athanassiadou of the UK Met Office.

“In bringing together such a wide range of disciplines and international perspectives, we have been able to show not just what works, but why it sometimes doesn’t.” 

Barriers for nature projects

Some environmental barriers arise when trees, wetlands, or green roofs clash with energy hardware such as photovoltaics, solar panels that turn sunlight into electricity.

Poorly designed wetlands can trap polluted runoff, release greenhouse gases, or add allergenic pollen, so careless planting can quietly trade one problem for another.

Professor Kumar noted that residents want more parks, street trees, canals, and living plant walls because these features cool cities, limit floods, and clean air.

“However, our research shows implementation too often lags behind policy priorities,” he said.

Richer cities have more green space

On the social side, the study highlights environmental injustice, patterns where marginalized communities get fewer high quality green spaces than wealthier neighbors.

Fear of crime, past exclusion from certain parks, or designs that do not match local culture can all make new projects feel unwelcoming.

A global analysis of nearly 500 cities revealed that green spaces cool richer cities far more than poorer ones in the Global South.

Studies also show that residents of greener neighborhoods enjoy better mental health and lower overall mortality.

These benefits reach beyond exercise, linking contact with trees and grass to less stress, fewer depressive symptoms, and a stronger sense of well being.

When new parks and trees appear mainly in privileged districts, they can push up property prices and deepen gaps in who enjoys cleaner air.

The researchers argue that designs and investments should start with local voices, making green spaces feel safe, welcoming, and worth caring for.

Money for environmental projects

On the economic side, the team found that city budgets undervalue biodiversity, the variety of living species that keep urban ecosystems stable and productive.

Many projects also go ahead without careful cost checks, so savings from cooler streets or reduced flooding never show up in official accounts.

Other work on nature-based solutions echoes these concerns, emphasizing that better finance and shared evidence are needed before cities invest at scale.

The experts call for better natural capital accounting, tools that record the value of trees, wetlands, and living assets alongside roads, pipes, and buildings.

Without these tools, the benefits of shade, cleaner air, and flood protection stay invisible when cities compete for limited investment money.

One option is to use green bonds, loans that raise money for environmental projects and follow guidelines in the Green Bond Principles.

These rules help investors see where their money goes and give cities a clearer case for funding climate ready parks, trees, and waterways.

Healthier cities with nature projects

The experts have proposed 12 recommendations focused on tailored design frameworks, fair investment in underserved areas, and active community involvement.

According to study co-author Dr. Ajit Ahlawat, the research provides empirical evidence that green and blue infrastructure constitutes a practical, actionable pathway for immediate climate action.

“By enabling policymakers to mainstream nature-based solutions, it offers a means to reduce emissions, mitigate climate risks, enhance urban resilience, and advance net-zero targets, while promoting healthier and more equitable cities for current and future generations.” 

The study is published in the journal The Innovation.

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