Trees, grass, and vegetation reduce the risk of mental health problems. It is a lesson urban planners must learn. Children who grow up surrounded by trees, grass and green spaces have a lower risk of developing mental illness later in life, according to Danish researchers.
Their findings, which involved almost a million Danes, were more than an interesting correlation: the risk of mental health problems varied directly with the amount of green space available to the child. As more people move to cities and mental health diagnoses appear to increase, the findings could have relevance for urban planning.
More than 450 million people suffer from a mental disorder, according to the World Health Organization. And this number is expected to increase. In some places, urban residents have nearly a 50% increased risk of developing anxiety and mood disorders compared to their rural counterparts, and the risk of schizophrenia is 200% higher for children growing up in rural settings. more urbanized.
Contact with nature has long been linked to better mental health; that is why sanatoriums and hospitals are often located in green surroundings. Living in a greener environment is believed to improve physical and mental health by promoting physical activity, increasing psychological restoration and recovery from stress, and strengthening social bonds in neighborhoods.
Mapping using satellite data
Researchers at Aarhus University used satellite data from 1985 to 2015 to map the amount of green space around Danish childhood homes. Because Denmark collects detailed health data on its citizens, the researchers were able to compare this data with whether the children developed one of the 16 mental disorders later in life.
Children surrounded by the most green space had up to a 55 percent lower relative risk of developing a mental disorder, even after the researchers adjusted for other known risk factors, such as socioeconomic status, urbanization and family history of mental disorders. The more green space a child had, the lower the risk of poor mental health.
This ‘dose dependent’ relationship was present across the country and in the Danish population, indicating that the association is more than just a correlation. Taking into account people moving to and from more urbanized areas, the research also showed that the risk of developing a mental disorder decreased with the amount of time a child was surrounded by green spaces from birth to age 10.
The same researchers further explored the concept in a survey of Danish blood donors. Around 66,000 people answered questions about their access to green spaces and ‘blue spaces’: bodies of water. Current mental well-being was associated with more green space around people’s homes. Calm was particularly associated with ‘blue space’. The researchers also found that the most physically active people had even stronger positive associations with green spaces.
Therefore, green spaces in childhood are extremely important, and therefore urban planning for access to natural environments for all ages is likely to have benefits.
The very large data sets for both studies strengthen the findings. Across time, geography, ‘dose’ level and large numbers of people, the patterns were the same. The results are part of a larger movement of scientific studies that have found a wide range of physical and mental health benefits from green spaces.
These studies are supported by many experimental studies in which scientists manipulated environments that showed that green spaces are linked to stronger cognitive development in children, reduced activity in brain areas linked to depression, and better recovery from depression. stress. Even exposure to nature in virtual reality has an effect.
Taking a greener approach
This knowledge can guide future urban planning, important because by 2050 more than two-thirds of the world’s population is expected to live in a city. The integration of more natural environments in urban areas can improve the mental health of city residents.
A greener approach to urban planning has the associated benefits of mitigating climate change, reducing the urban heat island effect, managing flood risk and conserving biodiversity. Working within and across research disciplines will ensure that the multifunctional potential of urban green spaces is fulfilled.
Local governments around the world are already starting to make cities greener. Denmark’s capital, Copenhagen, recently decided to transform one of its main thoroughfares into a park to improve access to green spaces, and Barcelona in Spain has launched an ambitious city-wide urban greening plan to promote the health of its citizens. and support biodiversity.
In a project in South Africa, Danish researchers are working with local partners to reinvent the city of Tshwane, Pretoria. The plan is to move towards a more habitable, healthy, equitable, biodiverse and climate change resistant city.
Nature-based solutions
Large international organizations such as the World Bank and the European Union have also seen the potential of green urban planning, including nature-based solutions, projects that address development problems while keeping the natural environment at the forefront.
Since 2012, the World Bank has supported nature-based solutions in about 100 projects in 60 countries, allocating $1.18 billion in 2019-20; and the EU provides funding for such projects through its Horizons 2020 programme. Competition for space is intense in the world’s densely populated cities, which means innovative approaches to green space design will be needed, for example , green walls and roofs.
Local perspectives and context are also important. Current studies on green spaces and mental health come mainly from developed economies, so they may not apply to developing economies. Involving local communities in planning decisions will help.
Kristine Engemann, Aarhus University in Copenhagen
Published in
May 27, 2022
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