Imagine the entire population of the UA vanishing.

No more students, professors, grounds keepers or maintenance workers.

Unnatural vegetation dependent on technology, like our famous grassy mall, would dry up and perish, gradually overrun by cacti and other native plants.

Huge buildings like the Student Union Memorial Center would be overwhelmed by nature. Cracks would form in the roof from the unrelenting desert sunlight, allowing water to enter the structure over-time, rusting away steal reinforcement, causing the building to crumble.

Eventually, mother nature would return the UA campus to the way it was before it was developed by human kind. Only traces of our campus’s existence would remain, like shopping bags from the UofA Bookstore, ubiquitous iPod cases and utensils used at our campus eateries.

This type of scenario is the subject of “”The World Without Us,”” by Alan Weisman, a UA associate professor of journalism and this month’s speaker at the Distinguished Lecture Series presented by the College of Social and Behavioral Sciences.

Yesterday, Weisman spoke to about 180 people about his book, named by Time magazine as the No. 1 nonfiction book of 2007.

Weisman’s lecture was one of the largest lectures held because the series usually draws 60 to 80 people, said Ginny Healy, director of development for the College of Social and Behavioral Sciences.

Weisman said “”The World Without Us,”” is a “”creative experiment”” where he describes a world where all people disappear in order to show a “”reverse way of looking at our impact on the world.””

Weisman said the process of writing his book was both staggering and fascinating.

While Weisman doesn’t wish for a world without people, he does hope the vision he creates in “”The World Without Us,”” will put our effect on the world into perspective and add knowledge that can help create a harmony between humankind and nature.

“”He is an amazing story teller, both in print and in speech,”” said Heather Raftery, a senior majoring in anthropology and journalism, who attended the lecture. “”He presents this broad and terrific idea so well that many people can understand its brilliance.””

“”Suppose all human activity ceased tomorrow, and suddenly there’s no one to produce plastic anymore. Just from what’s already present, given how we see it fragmenting, organisms will be dealing with this stuff indefinitely,”” Weisman said, quoting doctorate student Mark Browne in “”The World Without Us.””

Raftery said after reading Weisman’s book she became more aware of what she throws away and uses. Before reading the book, Raftery said she used a face-wash that contained plastic micro-beads. She learned that these beads get washed down the drain and eventually end up in the ocean, where they are ingested by sea creatures. The book caused her to “”freak out”” and she now only uses natural face washes.

If our race was to vanish, our legacy would be the billions and billions of pounds of plastics, which do not break down naturally, Weisman said.

He encouraged people to think about what materials they use.

The chapter “”Polymers are Forever,”” which has been republished by different news and scientific periodicals, explains the affect plastics have on the environment, like plastic bags

clogging “”everything from sewer drains to gullets of sea turtles.””

Another topic the lecture touched on was the booming human population. Every four days there are a million more people in the world, said Weisman, and we are coming to the edge of our resources to support this number of people. Useless we begin to manage our population, mother nature will regulate it for us, Weisman said.

He said every biological creature that overpopulates suffers a massive population loss when the creatures meet the edge of their resources.

Weisman said he was concerned about the planet when he started writing his book, but he says he now knows the planet will be just fine, it’s the future of human species for which he is now concerned.

Extinctions happen. Without the extinction of dinosaurs, it’s unlikely mammals, including humans, would have been able to flourish. Even if human kind were to suffer extinction, life would return in different forms, Weisman said.

“”The world unites us and the environment unites us,”” Weisman said. “”We must use our knowledge and take action, if we don’t, mother nature won’t care and she will move on without us.””

Weisman, whose articles have been published in Harper’s magazine, The New York Times Magazine and the Los Angeles Times Magazine, has written about various subjects.

He said the underlying theme of all of his articles is the environment.

He said he feels a responsibility to show human kind’s connection to the environment, something that unites every culture and race.

The best seller has been published in 30 countries. Weisman said he is a journalist presenting the facts on the subject and people can formulate their own opinions on the matter. He feels his book transcends politics and can reach out to people of any religious or political affiliation.

Like The Bible, Weisman’s book opens with a picture of paradise, lush nature, untouched by human hands. Weisman says that at a primal level, we still long for this natural beauty, a beauty that unfortunately is “”abandoned,”” shrinking day-by-day by the booming human population.

Even massive concrete and metal cites like New York would eventually return to lush forest without humankind. Ecosystems will develop no matter where, said Weisman. The book examines the walls put up by man between natures, walls that would fall apart without the human element.

Change can happen from the bottom up, Weisman said, and although he thinks it’s a sin the UA doesn’t use solar power technology, students shouldn’t wait for policy changes to be conscious of their effect on the environment.

Weisman said if students really want to make a difference on campus they should sneak onto the mall at midnight and tear up the grass, which wastes water and uses chemicals.

“”We don’t need the mall,”” said Weisman, adding the area would be better used as a farm for natural foods that could be eaten by students and used for education.