They converted old tires into a material that not only purifies water using solar energy—but also generates a small amount of electricity.

Giant African rats, already used to sniff out land mines, can do the same for smuggled rhino horns, elephant tusks and other common contraband, researchers report.

A new comprehensive study of “decoupling” finds that for 30% of the regions studied, the answer is yes. But the remaining regions are lagging behind.