Green buildings, leaky pavement and trees could help cities meet net zero carbon emissions: study

Dozens of cities in Europe could reach net zero carbon emissions within the next 10 years by incorporating nature into their urban infrastructure, according to new research.

A recent study published by researchers from Sweden, the U.S. and China in the scientific journal Nature Climate Change shows how 54 European cities could reduce carbon emissions by an average of 17.4 per cent using nature-based solutions like parks, streetscaping and rooftop gardens.

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The key to these and other solutions included in the study is that they can do more than just capture carbon emissions.

“Nature-based solutions not only offset a proportion of a city’s emissions, but can contribute to reduction in emissions and resource consumption too,” Zahra Kalantari, co-author and associate professor of water and environmental engineering at KTH Royal Institute of Technology, said in a media release.

For example, urban parks, green space and trees promote more walking, cycling and other environmentally-positive habits.

Other examples of nature-based solutions Kalantari and her co-authors studied include urban farming, permeable pavements which enable rainwater absorption into the ground, narrower roads with more greenery and trees and wildlife habitat preservation.

The research team studied data from previous studies on the effects of these solutions and found that by combining them, cities can sequester carbon, encourage low impact land use and travel, offset city and transportation carbon emissions, capture air pollutants, regulate temperature, increase access to green space and reduce the heat island effect associated with urban areas.

“There are many studies that examine the effects of individual nature-based solutions, but this merges all of them and analyzes the potential systemic effect,” Kalantari said. “That’s new.”

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The study also provides guidance on which measures should be prioritized and where to use them for the best effect, she said. In Berlin, for example, the study recommends prioritizing green buildings and urban green spaces for an emissions reduction rate of six per cent for residences, 13 per cent in industry and 14 per cent in transportation.

The also found the highest potential for carbon reduction was in eastern European Union cities, where nature-based solutions could reduce total carbon emissions by 20.3 per cent, followed by northern European Union cities, where carbon emissions could be reduced by 18.2 per cent.

While sequestering carbon – removing it from the atmosphere and trapping it in solid or liquid form – is a tried and tested method for reducing global climate change, the study found other nature-based solutions are even more effective, in part, because they influence human behaviour.

"The findings in this study have important policy implications in terms of the allocation and implementation of nature-based solutions for the goal of climate change mitigation," the study reads. "Successful implementation will require a much better understanding of the behavioural aspects of nature-based solutions and of the socioeconomic, industrial and cultural context of each city."