The wild world is good for you. Essential for you. Without the wild world your health suffers, your efficiency suffers, your effectiveness as a person suffers, your children are less than they might be, and you are less happy than you could be. The wild world is necessary for our sanity. Without nonhuman life, we are less than fully human.

Now it is all very well saying these things. In a vague sort of way, these assertions make a vague sort of sense: the sort of sense that you can’t put your finger on, the sort of sense that gets overridden when it comes down to the sort of thing you can actually prove – like such and such a development will make money; such and such a change will save money.

How can you measure good vibes? How can you measure tranquillity? How can you measure comfort and solace? How can you measure meaning? Impossible: so we flatten the wood for a new bypass that will enable us to get from one grim place to another at much greater speed; so we put up the new hospital unit in what was once the hospital garden; so we allow every town to spread until it joins its neighbour.

But now, astonishingly, we have a document that seeks to do all this measuring: to demonstrate, by experiment and by meticulously recorded observation, that the wild world has a measurable, a computable, value in society. The document offers physical proof of the spiritual benefits of the wild world. And if we find that a contradiction, it is only because the overwhelming trend of the past 200 years of human history have been based on material benefits for the human world.

But now we are beginning to discover the cost of this change. Now, as so much of the natural world has been destroyed, we are beginning to learn how important it is, not just for itself but for human beings. It is not simply that the natural world is nice. Rather, it is that the natural world is essential.

The document is called Natural Thinking; it has been produced by the wonderfully named Dr William Bird for the Royal Society for the Protection of Birds (RSPB), and The Times has been granted an exclusive first perusal of its contents. I met Dr Bird to talk over the thinking behind the paper while he was still putting it together, and have subsequently written some material for the RSPB on the subject, one very close to my heart.

Well, it’s close to all our hearts, whether we know it or not. But it has long been something I have quite explicitly believed in. Now, with this document, I have irrefragable proof. So let’s cut to the chase.

A study on patients recovering from gall-bladder surgery compared those who had a view of trees from a window, and those who could see only a brick wall. The tree group had shorter postop stays, fewer negative comments and fewer postop complications such as nausea and headaches.

A study in the US asked patients and staff in a hospital where they went when stressed. Of these, 95 per cent said that they got a positive change from being outside; 69 per cent said that plants and trees helped them best. Yet hospitals are the most nature-devoid buildings that human beings have ever come up with.

In another study, 166 patients facing open-heart surgery were shown one of four panels: an open, natural view with water; a closed forest; an abstract; or a white panel. The patients with the open, natural view had less postop anxiety. Patients undergoing bronchoscopy were given pictures of nature and recordings of birdsong. They all did better and needed fewer drugs than the control group who had nothing of the kind.

Dr Bird notes that for centuries hospitals were healing places that had restorative gardens, trees and courtyards. Now the stress is on artificial lighting, windowless rooms and abstract art that has been shown to increase stress levels in patients. The implication – not stated in the report but unmistakably present – is that we don’t need only to cure the bodies of the sick; we need also to care for their souls.

Sick people need nature. But then so do the well. Nature helps you to work better. Three groups of young adults: one took a holiday in the wild, the second a holiday in town, the third had no holiday. On return, each was given a highly demanding proofreading test. The wilderness group won by miles.

Another test: one group was assigned to a natural environment for 40 minutes, another to a city, another group listened to soft music and read magazines indoors. Again, the natural group won the subsequent proofreading test.

Dealing with stress is an essential aspect of 21st-century life. Working and the mere organisation of daily living are colossally demanding tasks. Stressed-out students were divided into three groups: one was shown videos of traffic, another of a shopping mall, another of nature. Guess which group unstressed quickest. Alpha-wave activity in the brain indicates a more relaxed state. Alpha waves are increased when you look at plants, especially if they have flowers. A group of young adults was divided in two: one group took an urban walk and found that anger and negativity increased. You can probably work out what happened to the group that took a walk in a nature reserve.

This is a drip-drip-drip process. One small piece of evidence after another wears down the conceptions that go with industrialised and urbanised life. And, in fact, most of us spend our lives seeking the natural world with an instinct like a salmon swimming upstream. To this end, we walk the dog, play golf, go fishing, do the garden, sit in the garden, drink outside rather than inside the pub, have a picnic, live in the suburbs, go to the seaside, buy a weekend place in the country. The most popular leisure activity in Britain is going for a walk. And when joggers jog, they don’t run the streets. Every one of them instinctively heads to the park or the river. It is my profound belief that not only do we all need nature, but we all seek nature, whether we know we are doing so or not.

But despite this, our children are growing up nature-deprived. I spent my boyhood climbing trees on Streatham Common, South London. These days, paedophile-phobia has robbed children of these ancient freedoms. Other problems are traffic, the loss of the open spaces and odd new perceptions about what is best for children. That is to say, things that can be bought, rather things that can be found.

The truth is to be found elsewhere. A study in the US: families had moved to better housing and the children were assessed for attention deficit and hyperactivity. Those whose accommodation had more natural views showed an improvement of 19 per cent; those who had the same improvement in material surroundings but no nice view improved just 4 per cent.

A study in Sweden indictaed that kindergarten children who could play in a natural environment had less illness and greater physical ability than children used only to a normal playground. A US study suggested that when a school gave children access to a natural environment, academic levels were raised across the entire school.

Another study found that children play differently in a natural environment. In playgrounds, children create a hierarchy based on physical competence, with the tough ones taking the lead. But when a grassy area was planted with shrubs, the children got much more into fantasy play, and the social hierarchy was now based on imagination and creativity.

Most bullying is found in schools where there is a tarmac playground; the least bullying is in a natural area that the children are encouraged to explore. This reminds me unpleasantly of Sunnyhill School in Streatham, with its brutal tarmac, where I used to lurk in corners fantasising about wildlife.

But children are frequently discouraged from involvement with natural spaces, for health and safety reasons, for fear that they might get dirty or that they might cause damage. So, instead, the damage is done to the children themselves: not to their bodies but to their souls.

And the report goes on, endlessly showing us the things we lose as we distance ourselves from the wild world. One of the great problems of modern childhood is ADHD – attention deficit hyperactivity disorder – now increasingly and expensively treated with drugs. Yet one study after another indicates that contact with nature gives huge benefits to ADHD children. However, we spend money on drugs rather than on green places.

The life of old people is measurably better when they have access to nature. The increasing emphasis for the growing population of old people is in quality rather than quantity of years. And study after study finds that a garden is the single most important thing in finding that quality.

In wider and more difficult areas of life, there is evidence to indicate that natural surroundings improve all kinds of things. Even problems with crime and aggressive behaviour are reduced when there is contact with the natural world.

Dr Bird’s study states: “A natural environment can reduce violent behaviour because its restorative process in the main helps reduce irritability and impulsive behaviour.” Wild places need encouraging for this reason, no matter how small their contribution.

We tend to look on nature conservation as some kind of cosmic favour that human beings are granting to the natural world. The error here is fathoms deep: not only do humans need nature for themselves, but the very idea that humanity and the natural world are separable things is profoundly damaging.

Human beings are a species of mammals. For seven million years they lived on the planet as part of nature. Our ancestral selves miss the natural world; crave contact with nonhuman life. Anyone who has patted a dog, stroked a cat, sat under a tree with a pint, given or received a bunch of flowers or chosen to walk through the park on a nice day, understands that.

We need the wild world. It is essential to our wellbeing, our health, our sanity, our happiness. It is not a luxury item, a bolt-on extra, something to keep so long as nothing more paying gets in the way. Without the wild world we are not more but less civilised. Without other living things around us we are less than human.

This is something we have always known in our hearts. Now we have a document that proves it.

Five ways to find harmony in the natural world

Walk Break the rhythm of permanently being under a roof. Get off a stop earlier, make a circuit of the park at lunchtime, walk the school run, get a dog, feel yourself moving in moving air, look, listen, absorb.

Sit Just as important: take a moment, every now and then, to be still in an open space. In the garden, anywhere that’s not in the office, anywhere out of the house, away from the routine. Sit under a tree, look at water, feel refreshed, ever so slightly renewed.

Drink The best way to enjoy the natural world is by yourself; the second best way is in company. Take a drink outside with a good person, a good gathering: talk with the sun and the wind with birdsong for background. Suggestions for drinks: tea, Robinson’s Barley Water, lager, Pimm’s, champagne. They all work.

Learn Expand your boundaries. Learn five species of bird, five butterflies, five trees, five bird songs. That way, you see and hear more: and your mind responds gratefully to the greater amount of wildness in your life.

Make pilgrimages The place you always wanted to visit: by the seaside, in the country, in the hills. Take a weekend break, a day-trip, get out there and do it: for the scenery, for the way through the woods, for the birds, for the bees. Go somewhere special: bring specialness home as a souvenir. It lasts for ever, after all.

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