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.

One of humanity’s greatest achievements over the past 50 years has been reducing global hunger—there are around 300 million ...