Earth Day is an appropriate time to think about the contribution of nature to our health. We all exist within regional and global natural ecosystems that are the fundamental determinants of our health. They provide the air, water and food without which we could not survive, and the energy and raw materials without which our societies would not have developed as they have.
But North Americans are 80 per cent urbanized, spending 90 per cent of our time indoors. The built environment is our most important environment, at least in terms of where we spend our time. We tend to overlook the fact that we — and all our built environments — exist within natural ecosystems.
More important, we are the product of millions of years of hominid evolution, with modern humans emerging a couple of hundred thousand years ago. Until the past few thousand years, all that evolution occurred in nature. Interestingly, landscape preference research has found that across many cultures, we tend to have a preference for savannah-like landscapes, similar to the environment in which modern humans evolved.
So while we might seem to be an urban species, divorced from nature, we are in fact a natural species misplaced in urban settings.
Recently, there has been growing interest in the health impacts of our divorce from nature and the health benefits of contact with and connection to nature. It seems that contact with nature is fundamental to our physical, mental and social well-being and our intellectual development.
In 1984, Roger Ulrich at Texas A&M University reported that post-surgical patients who had a view of nature recovered more quickly and needed fewer painkillers than patients with a view of a brick wall.
Subsequent research has found that simply seeing pictures of nature can be helpful, while a “healing garden” can reduce stress, improve mood and increase satisfaction among patients, families and staff.
One particularly interesting set of results comes from Frances Ming Kuo at the Landscape and Human Health Laboratory at the University of Illinois. She compared people living in identical social-housing estates where, by chance, some had quite “green” environments (lots of vegetation) and others did not. She found:
• The greater the amount of greenery in common spaces, the higher the levels of mutual caring and support among neighbours;
• The more vegetation, the lower the crime rate;
• Higher levels of residential greenery are associated with lower levels of aggression against domestic partners;
• The more natural the view from home, the better girls scored on tests of concentration and self-discipline;
• The more greenery, the higher levels of optimism and sense of effectiveness;
• The greener the setting in which children with attention-deficit disorder spend time, the more their symptoms are relieved.
These are remarkable results. But what is also important is that this is social housing, so these are people who are already disadvantaged. To further disadvantage them by providing less green environments seems to add insult to injury.
Yet we have solid evidence that access to and contact with nature is related to income. People with higher incomes live closer to parks, and their parks are in better condition, than those living in low-income communities. And of course they are more likely to be able to afford to travel to and spend time in wilderness.
Given the health benefits of contact with nature, the policy challenge we face is not how to get people to nature, important though that might be, but how to get nature to people. We will never get all the people in our cities out to the wilderness on a regular basis (and if we did, the wilderness would suffer).
So how do we bring nature into homes and streets, schools and neighbourhoods?
These are important issues for governments to consider. We need more pocket parks, street trees, school and community gardens and other green assets in our communities. Even more important, we need to preferentially increase access to and contact with nature for low-income urban populations, whose needs for such access and contact are greater.
Dr. Trevor Hancock is a professor and senior scholar at the University of Victoria’s school of public health and social policy.