Spending time in nature is proven to help us think and feel better, but people are increasingly disconnected from it. Now, an international team led by Stanford University and the University of Washington has developed a conceptual model to help urban planners and developers predict the mental health repercussions of adding or taking away nature as they make land-use decisions.

A paper detailing the work appears in Science Advances. As a story from the Stanford Natural Capital Project explains, nearly two-thirds of the global population will live in cities by 2050, and often removed from nature. At the same time, an estimated 450 million people are living with a mental or neurological disorder, and many of them are city dwellers. The research focuses on the connections between these trends and what can be done.

Ecosystem models have emerged as an important tool for planners to justify how investing in nature benefits society. When deciding whether to build a new park or restore a river, for example, city planners can consider the improved air and water quality, flood protection and increased physical activity that might result. But as the researchers note, relatively little attention has been given to the ways nature affects human mental health.

Ultimately, the Stanford Natural Capital Project plans to build the mental health tool into its planning software suite InVEST, which is used by planners in 185 countries to quantify the many services — like water purification, flood risk mitigation and recreation opportunity — that nature provides to people.

"If the evidence shows that nature contact helps to buffer against negative impacts from other environmental predictors of health, then access to these landscapes can be considered a matter of environmental justice," said study lead author Greg Bratman, PhD, a former Stanford postdoctoral scholar and current assistant professor at the University of Washington. "We hope this framework will contribute to the discussion."

Photo by Mathew Waters