One of the biggest challenges of the 21st century will be figuring out how to feed our rising global population. Now, some scientists are making the radical claim that growing more food won't be enough.
Nature doesn't end at city borders, it's just transformed. That's why scientists are finding new animal species in urban areas, where the ecosystems favour scavengers, weeds and junk-eaters – and it comes as no surprise that Los Angeles has its own unique fly species.
Dairy farmers routinely feed their cows finger-sized magnets that settle in their digestive tracts to help keep them healthy. This is not bizarre homeopathy, but a legitimate treatment for a stomach-churning ailment called "hardware disease".