"What Makes Us Human?": Comparisons of the genomes of humans and chimpanzees are revealing rare stretches of DNA that are ours alone.
"Could Food Shortages Bring Down Civilization?": One of the biggest threats to global stability is the potential for food crises to cause government collapse in poor countries.
"The Planetary Air Leak": Many of the gases that make up Earth's atmosphere are slowly leaking into outer space.
"How to Steal Secrets Without a Network": Information thieves can now do an end run around encryption, networks and operating systems.