In the 19th century, the American West was an arid climate yet to be fully explored. But surveyors like geologist John Wesley Powell, the second director of the United States Geological Society, would chart out the natural wonders that lied beyond the Mississippi. While at the USGS, Powell would lead a project to create the first map of the country to integrate geographical features and some of the first survey expeditions along the snaking Colorado River and Grand Canyon. But he also proposed radical ideas about developing the West that took the climate and ecology into account. One of Powell’s theories stated that the U.S. was divided down the middle along the “100th Meridian”—between the dry West region and moist East. In two recent studies, climatologist Richard Seager and his team confirmed this dividing line. Seager joins Ira to explain how this ecological division has changed due to climate change. Shortly after the Declaration of Independence was signed, Congress chose the bald eagle—a symbol of freedom—as the national bird. There were an estimated 100,000 eagles at that time. But the birds were nearly driven to extinction in the 1960s, with only with only 487 breeding pairs out in the wild. After the endangered species list was created and targeted conservation efforts began, eagle populations recovered. Researchers have found that one of the keys to recovery is protecting the nest of breeding pairs of eagles. Subscribe to this podcast. Plus, to stay updated on all things science, sign up for Science Friday's newsletters.

Ask this episode

“What did the council decide on item 42?” — answered with the speaker and the moment.