Why going to a park is better than going to the beach

My father was always disapproving of people who excused their failure to turn up to his Sunday meeting by saying they'd been "worshipping God in the great outdoors". But the older I get, and the more I read, the more I think it's not such a bad idea.

I'm much attracted by the American biologist Edward O. Wilson's hypothesis of biophilia, that humans have an innate tendency to seek connection to nature, for its calming effects.

While most people will be heading for the beach in the next few weeks, I usually head for a national park, to lift my quota of trees, bush, grass and anything else that's green.

This time, however, we're heading for a jungle – otherwise known as Manhattan – to do babysitting duty. Ideally, this means I'd be virtually living in Central Park, but that may be a bit too snowy.

My regular reading of the universities' blogsite, The Conversation, has garnered a fair bit of evidence for biophilia.

According to a survey conducted by the Australian Bureau of Statistics in 2007, each year one in five Australians experiences a mental disorder. Most common are anxiety disorders, such as panic attacks or obsessive-compulsive disorder.

Zoe Myers, an urban design specialist at the University of Western Australia, says research shows that city dwellers have a 20 per cent higher chance of suffering anxiety and an almost 40 per cent greater likelihood of developing depression.

Fortunately, research also shows that people in urban areas who live closest to the greatest green space are significantly less likely to suffer poor mental health.

Myers says more than 40 years of research shows that exposure to nature increases calm and rumination, decreases agitation and aggression, and improves concentration, memory and creative thought.

But it's not emptiness or quiet that has these good effects, she says. "Nature in its messy, wild, loud, diverse, animal-inhabited glory has most impact on restoring a stressed mind to a calm and alert state.

"This provides a more complete sense of 'escape' from the urban world, however brief."

Many studies have attested to the restorative effects of forests but, though holidays in national parks are nice, we need something closer to home.

Melanie Davern, of RMIT University, with colleagues from Melbourne University, say recent research on the benefits of urban greening has found, for instance, lower rates of anti-depressant prescriptions in neighbourhoods close to woodlands in Britain, happier people living in areas with more birdlife, and better health in areas with increased neighbourhood tree coverage in the United States.

Planting trees in parks, gardens or streets has many benefits: cooler cities, slower stormwater run-off, filtering of air pollution, habitat for some animals (such as birds, bats and bees), making people happier and providing shade that encourages more walking.

Professor Pierre Horwitz, of Edith Cowan University, is a great advocate for urban bushland – a bush park of native trees, a wetland, or any native vegetation characteristic of the local region.

"With its undisturbed soils and associated wildlife, urban bushland is more diverse than other types of green spaces in our cities, like parks. The more unfragmented the landscape, or unaltered the bushland, the more likely it will be to retain its biodiversity," Horwitz says.

"Exposure to biodiversity from the air, water, soils, vegetation, wildlife and landscape, and all the microbes associated with them ... enhances our immunity. This is thought to be key to the health benefits of nature."

Horwitz says we know that wealthier people tend to live in greener suburbs, and that wealthier people tend to be healthier. So is it wealth rather than nature that's doing the good work?

Fortunately, no. Many studies have controlled for wealth but still found direct health benefits from exposure to biodiversity.

The benefits go not just to individuals, but to the wider city. Forests and woodlands clean our urban air by removing particles and absorbing carbon dioxide. This reduces premature death, acute respiratory symptoms and asthma across the city.

As well, urban bushland improves city water. Wetlands and the vegetation around them clean water by filtering, reducing exposure to pollutants carried in groundwater or surface run-off.

And not forgetting that vegetation moderates extremes of temperature, providing shade when it's hot and less exposure when it's cold, thus reducing heat- or cold-related illnesses.

Trouble is, urban bushland shrinks as new suburbs are developed on the outskirts of our cities. Worse, bigger houses and more high-rise living is causing backyards to be shrinking, too, even though they contribute to our health and our kids' development.

Not to worry. There's a lot of urban roof space, and we're getting more rooftop gardens. Sara Wilkinson and Fiona Orr, of the University of Technology Sydney, studied the use of a rooftop garden at St Vincent's Hospital in Sydney as part of two "horticultural therapy" programs for people recovering from mental illness.

Among the many benefits participants identified were regular connection with others, developing friendships, experiencing enjoyment and restoration of health.

And if you don't have a spare rooftop, you can join the latest trend and install a vertical garden.

Sorry, I'm getting a bit over-excited here. I wonder if "green space" still counts as green when its covered in snow? Hope the apartment we're renting at least has some indoor plants.

Read more >>

Sydney too must go up to go green

As a denizen of the inner city, I love getting away to the countryside. Away from the tar and cement and exhaust fumes to the trees and grass and clean air. In the country or on the coast you feel closer to nature, leading a simpler, cleaner life, doing less damage to the environment. I always feel that, being more natural, trees and grass are good for the spirit.

So it comes as a bit of a shock to read in Triumph of the City, the latest book by America's leading urban economist, Professor Edward Glaeser, of Harvard, that cities are a lot greener than the suburbs and countryside.

''Cities are much better for the environment than leafy living,'' Glaeser says. ''Residing in a forest might seem to be a good way of showing one's love of nature, but living in a concrete jungle is actually far more ecologically friendly.

''We humans are a destructive species, even when ? we're not trying to be. We burn forests and oil and inevitably hurt the landscape that surrounds us. If you love nature, stay away from it.''

We could minimise our damage to the environment by clustering together in high-rises and walking to work, he says. We maximise our damage when we insist on living surrounded by greensward. Lower densities inevitably mean more travel, and that requires energy. While larger living spaces certainly have their advantages, large suburban homes also consume much more energy.

Anyone who believes global warming is a real danger should see dense urban living as part of the solution. Over the next 50 years, China and India will cease to be poor rural nations, and that's a good thing. They, like the West before them, will move from farms to urban living.

''If billions of Chinese and Indians insist on leafy suburbs and the large homes and cars those suburbs entail, then the world's carbon emissions will soar ? The critical question is whether, as Asia develops, it will become a continent of suburban drivers or urban-transit users.''

Historically, the wealthy managed to combine city and country living by having two homes. Winter months were spent in the city, while hot summers were spent on the country estate.

Less expensive solutions were to surround towns and cities with a green belt. Failing that, big city parks were established. But the emergence of faster, cheaper transportation made it possible to live with trees and work in the city.

Homes and cars account for about 40 per cent of the average American household's emissions of carbon dioxide, half of which is attributable to cars. People could buy more fuel-efficient cars, but the big difference is whether you drive 500 kilometres a year or 50,000, which depends on whether you live in a city or a suburb. Cities are also greener than suburbs because city households use less electricity.

''Smart environmentalism requires thinking through the inadvertent side-effects of different environmental policies and recognising those that actually do more harm than good,'' Glaeser says. The conservationists who keep the San Francisco Bay area free from new construction are preventing development in the greenest part of America. They are consequently increasing development in America's browner areas, such as baking-hot, air-conditioned Texas.

''In older cities like New York, NIMBYism hides under the cover of preservationism, perverting the worthy cause of preserving the most beautiful reminders of our past into an attempt to freeze vast neighbourhoods filled with undistinguished architecture.

''In highly attractive cities, the worst aspects of this opposition to change are that it ensures that building heights will be low, new homes will be few, prices will be high, and the city will be off-limits to all but rich people.''

People seem surprisingly ignorant of how supply and demand work. When the demand for a city rises, prices will rise unless more homes are built. When cities restrict new construction, they become more expensive.

Cities grow by building up or out. When a city doesn't build, people are prevented from experiencing the magic of urban proximity. Preserving a city can, in fact, require destroying part of it, Glaeser says.

The modern desire to preserve Baron Haussman's Paris has helped turn the affordable Paris of the past - with its history of impecunious but ultimately celebrated artists - into a boutique city that today can be enjoyed only by the wealthy.

There is great value in protecting the most beautiful parts of our urban past, but cities shouldn't be embalmed in amber. Too much preservation stops cities from providing newer, taller, better buildings for their inhabitants.

Height restrictions - in Paris, New York and Mumbai - should be of interest and concern to far more of us than just the planning professionals. ''These rules are shaping the future of our cities and our world,'' Glaeser says. ''If the cities' history becomes a straitjacket, then they lose one of their greatest assets: the ability to build up.''

Height, he says, is the best way to keep prices affordable and living standards high.

Glaeser's observations seem of obvious relevance to Sydney and the decisions facing the O'Farrell government. Our sky-high house and unit prices are partly the product of strong demand being met by a woefully inadequate supply of additional houses and units. Now those high prices are contributing significantly to Sydney and NSW's weak rate of economic growth.

The lack of additional supply comes partly from our topography, but mainly from excessive government restrictions on development. But there are limits to how far Sydney can be allowed to sprawl - including the inadequacy of public transport.

Sydney needs to go up, and part of that up is more medium-density housing in north shore Liberal electorates, including the Premier's own.

Read more >>

Great cities inspire us to reach for the sky

As I'm sure you've heard, for the first time in human history more than half the world's population lives in cities. In the developing countries, particularly China, the urban population is growing by 5 million a month. In rich and poor countries alike, cities are a magnet. But why are people so keen to crowd into congested, expensive cities?

The explanation has to be primarily economic, but most economists studiously ignore the spacial dimension of economic activity. There is, however, a notable exception: Professor Edward Glaeser, of Harvard University, is one of the world's leading experts on urban economics.

In his new book, Triumph of the City, Glaeser proclaims cities to be humans' greatest invention. Why? Because they make us rich. ''Urban density provides the clearest path from poverty to prosperity,'' he says. People who live in big cities not only earn a lot more than those who don't, they're more productive.

Cities are ''the absence of physical space between people and companies''. This closeness generates ''economies of agglomeration''. Producing a product close to a large market cuts costs by allowing large-scale production and reducing distribution expenses. The bigger the city, the greater the scope for firms to specialise in particular fields. Firms know they'll have less trouble finding the labour they need in a big city; workers come to cities knowing there'll be plenty of good jobs.

Historically, big cities often arose because they were convenient hubs for national or international trade in particular products. Many developed their own manufacturing industries - garment-making in New York, cars in Detroit, for instance. But such areas of strength can be challenged by changes in technology. Big reductions in the cost of transport and communications have brought about ''the death of distance'' and shifted much manufacturing to developing countries where labour is cheaper.

Detroit has never recovered from greater competition with Japanese and other Asian carmakers. Its population is less than half what it was. New York lost most of its manufacturing industry, but began reinventing itself in the 1970s. Today, more than 40 per cent of Manhattan's payroll is the financial services industry.

This experience leads Glaeser to emphasise a different driver of the benefits of cities: knowledge.

''Humans are an intensely social species that excels, like ants or gibbons, in producing things together. Just as ant colonies do things that are far beyond the abilities of isolated insects, cities achieve much more than isolated humans,'' he says.

''Cities enable collaboration, especially the joint production of knowledge that is mankind's most important creation. Ideas flow readily from person to person in the dense corridors of Bangalore or London, and people are willing to put up with high urban prices just to be around talented people, some of whose knowledge will rub off.''

Cities magnify humanity's strengths. Because humans learn so much from other humans, we learn more when there are more people around us. Urban density creates a constant flow of new information that comes from observing others' successes and failures. Cities make it easier to watch, listen and learn.

Pundits have predicted that improvements in information technology will make urban advantages obsolete. Once you can learn from Wikipedia in Gilgandra, why pay Sydney prices?

''But a few decades of high technology can't trump millions of years of evolution,'' Glaeser says. ''Our species learns primarily from the aural, visual and olfactory clues given off by our fellow humans. The internet is a wonderful tool, but it works best when combined with knowledge gained face to face, as the concentrations of internet entrepreneurs in Bangalore and Silicon Valley would attest.''

An experiment challenged groups of six students to play a game in which everyone could earn money by co-operating. One set of groups met for 10 minutes' face-to-face to discuss strategy before playing. Another set had 30 minutes for electronic interaction. The groups that met in person co-operated well and earned more money. The groups that only connected electronically fell apart, as members put their personal gains ahead of the group's needs.

This fits with many other experiments, which have shown that face-to-face contact leads to more trust, generosity and co-operation than any other sort of interaction.

Cities, and the face-to-face interactions they engender, are tools for reducing the ''complex-communication curse''. Long hours spent one-on-one enable listeners to make sure they get it right. It's easy to mistakenly offend someone from a different culture, but a warm smile can smooth conflicts that could otherwise turn into flaming emails.

Glaeser says the ''central paradox of the modern metropolis'' is that proximity has become even more valuable as the cost of connecting across long distances has fallen. His explanation is that the declining cost of connection has only increased the monetary returns to clustering close together. Before, high transport costs limited the ability to make money quickly from selling a good idea worldwide. ''The death of distance may have been hell on the goods producers in Detroit, who lost out to Japanese competitors, but it has been heaven for the idea producers of New York, San Francisco and Los Angeles, who have made billions on innovations in technology, entertainment and finance.''

So what do you have to do to be a successful city? Well, first, you have to overcome the three main costs of cities: disease, crime and congestion. After you've achieved clean water (solved the sewerage problem), the harder goals are safe streets, fast commutes and good schools.

Cities thrive when they have many small firms and skilled citizens. Industrial diversity, entrepreneurship and education lead to innovation. Innovation allows cities to overcome setbacks and stay prosperous.

''Human capital, far more than physical infrastructure, explains which cities succeed,'' Glaeser concludes. ''Infrastructure eventually becomes obsolete, but education perpetuates itself as one smart generation teaches the next.''

Read more >>