Overpopulation and excessive consumption are continual world problems and will remain so until changes in society are made.

That was one of many messages on the difficulties in the world from scientist and author Paul Ehrlich during a lecture Monday night at LaSells Stewart Center on the Oregon State University campus.

Ehrlich — the Bing Professor of Population Studies at Stanford University and the author of many books, including the well-known "The Population Bomb" and "Human Natures" — also touched on perceived problems with the current Bush administration and the environment.

"The last thing we should be doing is finding more fossil fuels to burn," Ehrlich said, noting the United States invasion of Iraq, which he says was partially because of the oil there. He said Bush would not have invaded Iraq if was the world's largest producer of broccoli.

Ehrlich pointed to the world's hunger, over-consumption of resources and economic inequity as examples of the planet's problems. Between 600 million and 800 million people of the 6.3 billion on Earth don't get enough food. About 300 million people live on roughly $2 a day. Most subsidies go to the rich, not the poor, he said.

"We are in a sense a triumphant species. But why should we worry?" said Ehrlich, who was awarded the Crafoord Prize of the Royal Swedish Academy of Sciences, given in lieu of a Nobel Prize in areas where the Nobel is not given. "There are aspects of the of the triumph that aren't so triumphant."

How do you control overpopulation?

Ehrlich said one way is to make more women literate. He pointed to research that, in general, women who can read have lower birth rates than those who can't. Slowing consumption of resources also needs to be addressed, though Ehrlich didn't have a precise answer for that.

"Most people … understand there are too many people on the planet, and we need to find humane ways to reduce the numbers," he said in front of a mostly student audience of several hundred.

Ehrlich said caring for the environment is being left behind as the world continues to grow in population. He said the primary solution being discussed is recycling.

"They don't tell you that we can recycle until we're blue in the face and delay the end by three and a half hours." Ehrlich said, drawing laughter from the crowd.