This is an archived article that was published on in 2011, and information in the article may be outdated. It is provided only for personal research purposes and may not be reprinted.

Habitat fragmentation, invasive species and human population growth already combine to threaten some wildlife populations.

Now, climate change could cause even more serious problems for the Earth's wild creatures, biologist Anthony Barnosky said Friday at the Wallace Stegner Center for Land, Resources and the Environment's 16th annual symposium.

"What we regard as normal today is already an extremely reduced biodiversity," said Barnosky, an integrative biology professor at the Univeristy of California, Berkeley.

If predictions hold, the world could be hotter in 2040 than at any time since humans have inhabited the Earth, he said. Global warming will force wildlife species to move around the globe to find habitat that suits them.

Under a best-case scenario, temperatures will warm by four degrees between now and 2100. Worst-case studies show temperatures could rise by six or seven degrees.

One remedy may be to protect more of the Earth's surface as nature reserves or national parks, Barnowsky said.

Another may be to manage wildlife relocation to new habitats. This could save climate-threatened species. "But the cost is the impacts on other species involved in a human-constructed ecosystem," he said.

Some scientists speculate the world could be starting a "sixth extinction" that would wipe out 75 percent of the Earth's species. They estimate it could begin anytime between 300 and 2,200 years from now.

Nonetheless, Barnowsky remains optimistic. He cited Wallace Stegner's writing of the "geography of hope," saying he has faith in people's ability to recognize a problem and be resourceful in solving it.

"We need to think of different resources," he said. "An all-in-one conservation approach will no longer work."

Other speakers, including Robert Keiter, director of the University of Utah's Stegner Center, and Jodi Hilty, of the Wildlife Conservation Society, echoed Barnowsky's concerns.

They used Wyoming's migratory antelope herds as an example of increasing wildlife habitat fragmentation.

"How do we conserve wildlife when habitat needs to not correspond to existing political boundaries or management priorities, when the landscape is used and fragmented, when nature is unstable and unpredictable, and the specter of climate change looms?" Keiter asked.