"Perfect Storm" Killing Earth's Frogs

Amphibians like the red-legged frog are Earth's ultimate tough guy. For millions of years they've endured - even through previous mass extinctions. But now scientists say their numbers are declining at a rate that sends a deafening warning about human impact on climate change and the environment, CBS News science and technology correspondent Daniel Sieberg reports.

"These guys are survivors, yet here they are in our time, when more than 40 percent of amphibians around the world are threatened," said Vance Vrendenburg, associate professor at San Francisco University.

Climate change and disease are seen as the most serious threats to amphibians like the harlequin frog from Equador - specifically, a fungus known as chytridiomycosis.

"The perfect storm is happening," Vrendenburg said. "All these different factors are leading to their decline, and it's really, really serious. We've been finding dead frogs by the hundreds and thousands."

The new report comes as the Department of the Interior is proposing changes to the Endangered Species Act that would eliminate the need for an independent scientific review in certain cases when it comes to assessing how federal projects, like dams or highways, might affect protected species.

"If you ran into a problem where you really were concerned about something and wanted to do detailed scientific analysis, these rules would make it much harder to do that," said Steve Cohen of Columbia University.

But others say the current regulations are unnecessarily restrictive.

"The Endangered Species Act has evolved into something that is less concerned with helping species and more concerned with exerting economic control and holding up - or sometimes stopping - important economic activity," said Ben Lieberman of the Heritage Foundation.

That thinking baffles Cohen.

"We're very dependent on the same environment those animals are dependent on; so like a canary going down into cave, if the canary dies, we're next," he said.

Environmental groups are outraged today. But the Department of the Interior says it's a necessary move to prevent the Endangered Species Act from being used as a "back door" to regulate gasses blamed for global warming.