How Urban Green Space Affects Happiness Worldwide

There’s lots of research that finds that being in nature is good for your well-being. But most of the studies that evaluate the benefits of being outdoors and spending time in green space have been performed in just one country at a time, and only in a handful of nations.

A new study uses satellite imagery to find that urban green space is linked to happiness in 60 countries around the world.

Researchers were driven by a lack of global data on the relationship between a happy mindset and outdoor blocks of greenery.

“Urban environments reshape the lifestyle of citizens. We thought greenery and happiness would be connected somehow, but there was a lack of studies on the global relationship between them,” researcher Oh-Hyun Kwon of Pohang University of Science and Technology in South Korea tells Treehugger.

“Hence, we used satellite imagery data to measure green space in many different countries.”

For the study, they collected data from the Sentinel-2 satellites. These are twin Earth-observation satellites developed and operated by the European Space Agency to collect high-resolution imagery of agriculture, forests, land-use changes, and land-cover changes.

The team calculated a vegetation index in the most populated cities to measure each country’s urban green space score. They chose 90 cities in 60 countries in order to make sure they were representing at least 10% of the population in the countries they were studying.

For the clearest view, they only used satellite imagery data in the summer, which is June to September in the Northern Hemisphere and December to February in the Southern Hemisphere. They worked with happiness scores calculated by the United Nations in the World Happiness Report.

They found a positive correlation between happiness and urban green space in all the countries they studied. Urban green space added extra happiness compared to the happiness value already determined by a nation’s overall wealth.

The team studied whether this was the same in all countries. They found that happiness in the top 30 wealthiest countries (gross domestic product or GDP per capita of $38,000 or more) is strongly affected by the amount of green space. However, the GDP per capita is a more important factor that determines happiness in the bottom 30 countries.

“First, we observe that urban green space and happiness are correlated with an economic variable (GDP per capita) across 60 developed countries. Note that we studied the cross-sectional relationship between different countries, not the correlation within a single country,” Kwon says.

“Second, we show that the correlation between urban green space and happiness is much stronger for the top 30 wealthiest countries. Last, we find that social support plays an important part in urban green space and happiness relations.”

The results were published in the journal EPJ Data Science.

Urban Planning Resources

This new study goes well beyond earlier research which was much more limited.

“Previous research usually studied green space in a single country. Most of these studies have been conducted in the United States and Europe. Moreover, only a few are based on multi-country settings that enable comparative analysis,” Kwon says.

“Various methods of measuring green space—questionnaires, qualitative interviews, satellite images, Google Street View images, and even smartphone technology—still rely on individual-level measurements and hence are not scalable to the global level. By using satellite imagery and defining a green space metric which is scalable at the global level, we were able to compare urban green space in different countries.”

The researchers suggest that the results can be used for successful urban planning. They propose a model for estimating the amount of urban green space to promote happiness considering each country’s economic status.

“This value can be considered as one parameter for happiness in urban planning,” Kwon says. “Also, our paper discussed securing land for green space. It would be challenging or nearly impossible to secure land for green space after built-up areas are developed in cities. Urban planning for parks and green recovery (new greening in built-up areas) should be considered in developing economies where new cities and suburban areas are rapidly expanding.”