Farms outside Baghdad as seen from a U.S. Army Blackhawk helicopter. Much of Iraq's soil has a high salt content because of flooding and poor drainage. Jim Gordon/U.S. Army Corps of Engineers/Flickr hide caption

itoggle caption Jim Gordon/U.S. Army Corps of Engineers/Flickr

These scuba divers are among the 2 million tourists who visit the Great Barrier Reef each year. They contribute about $5.6 billion to Australia's economy, according to the Queensland government. Steve Dorsey for NPR hide caption

itoggle caption Steve Dorsey for NPR

The San Luis Reservoir in central California is the largest "off-channel" reservoir in the U.S. It is currently at less than 30 percent of its normal capacity. Kirk Siegler/NPR hide caption

itoggle caption Kirk Siegler/NPR

The restoration's goal is to put as much of the Kissimmee as possible back to the way it was. This photo shows the river after restoration. Courtesy the South Florida Water Management District hide caption

itoggle caption Courtesy the South Florida Water Management District

Researchers say there's plenty the beef industry can do to use less land and water and emit fewer greenhouse gas emissions. But producers may need to charge a premium to make those changes. iStockphoto.com hide caption

itoggle caption iStockphoto.com

Corn farmer Jerry McCulley sprays the weedkiller glyphosate across his cornfield in Auburn, Ill., in 2010. An increasing number of weeds have now evolved resistance to the chemical. Seth Perlman/AP hide caption

itoggle caption Seth Perlman/AP

Millennials seem to prioritize the environment, but may want to dissociate from the "treehugger" baggage of the term "environmentalist." Getty Images hide caption

itoggle caption Getty Images