A little over a century after early explorers took the first photographs of Muir Glacier in Alaska, the same location is unrecognizable today. By 2005, the glacier had shrunk back completely out of view, and mountains were covered with trees instead of snow and ice.
Side-by-side photos of the glacier are part of a collection called Images of Change that NASA has curated since 2009. Each week, the team searches through images from NASA’s collection of satellites (and occasional photographs taken from land), looking for ones that draw into focus how our cities have sprawled and our landscapes have changed. One focus of the site is climate change.
“Climate change is kind of an abstract concept for most people, or it feels like it’s something that happens invisibly or it’s going to happen in the future,” says Randal Jackson, Internet manager for NASA’s Jet Propulsion Laboratory. “The Images of Change gallery gives us an opportunity to make it feel a little bit more real.”
The view from space makes large-scale changes more obvious. In Kazakhstan, the photos show how the Aral Sea, once the fourth largest sea in the world, has dried up for the first time in 600 years. In Kenya, the photos show Nairobi–a city that didn’t even exist until around 1900–sprawling over the last few decades to a population of over 3 million. In Singapore, we can see artificial islands transforming the coastline.
Not every change is negative. One pair of images shows forests growing back in Uganda, while another shows air pollution starting to disappear in the U.S. The rest of the collection may help spur action by helping the broader public–not just the scientists who use satellite images in daily work–better understand how quickly change can occur.
“People see concrete evidence of our changing planet,” says Holly Shaftel, who curates the images. “Especially when we post images of glacial retreat, they tend to say, ‘Why aren’t we doing something about this?'”