Worth a Thousand Words

摘要

In 1868, British soldiers lugged a 500-kilogram camera into the Ethiopian mountains—not to shoot snapshots, but to photocopy documents for headquarters. Occasionally, however, they trained the lens on their surroundings. Now, 145 years later, the antique photos provide a unique window into how climate change and other factors have affected Ethiopian ecosystems. By comparing the historic images with modern photos snapped at the very same spots, researchers are documenting biological shifts that might be otherwise invisible. And Ethiopia isn't the only locale captured in historic photographs: Researchers have also turned up valuable troves from China and the Arctic. The photographs represent "a very powerful ecological tool," says Isla Myers-Smith, an ecologist at the University of Edinburgh in the United Kingdom.