Each of us-adult or child-must earn nature's gift by knowing nature directly, however difficult it may be to glean that knowledge in an urban environment.

Nature-deficit disorder describes the human costs of alienation from nature, among them: diminished use of the senses, attention difficulties, and higher rates of physical and emotional illnesses. The disorder can be detected in individuals, families, and communities.

The Centers for Disease Control (CDC) reports that the number of overweight adult Americans increased over 60 percent between 1991 and 2000. According to CDC data, the U.S. population of overweight children between ages two and five increased by almost 36 percent from 1989 to 1999.

How can our kids really understand the moral complexities of being alive if they are not allowed to engage in those complexities outdoors?

Being close to nature, in general, helps boost a child's attention span.

If a child never sees the stars, never has meaningful encounters with other species, never experiences the richness of nature, what happens to that child?

In medieval times, if someone displayed the symptoms we now identify as boredom, that person was thought to be committing something called acedia, a 'dangerous form of spiritual alienation' -- a devaluing of the world and its creator.