Mayr says many people are complaining about the destruction of the rain forests, but few are doing anything about it.

"Everyone talks about biodiversity, but I haven't seen any new jobs," Mayr says.

Mayr cites the population explosion as fueling the demise of the rain forests.

"When you have someone like the Pope saying 'have more children,' you have a population explosion," Mayr says. "In the West, we don't even replace ourselves with children."

Mayr feels strongly that the population must examine their ethics closely, and that "everyone should try to contribute instead of just taking."

"I believe in community ethics while the Pope preaches individual ethics," Mayr says. "If a fetus can be diagnosed as having Down's syndrome, community ethics dictate that the baby should be aborted, but individual ethics say that the mother will want to keep the baby."

"Individual ethics cause many of society's burdens," Mayr says. "But there is a danger where community ethics leads to totalitarian states. There must be a balance."

Mayr believes "difficult issues" like these are the ones that tomorrow's leaders must consider.

And if his parting words are any indication, Mayr plans to be right there when they do so.

"Come back and congratulate me on my 100th birthday," he says