Jellyfish blooms can swamp entire ecosystems, but there's growing interest in their culinary potential. But could this really solve the ocean's problems?
Rooftop solar panels are offering the promise of a more normal way of living in Lebanon amidst an unsteady electricity supply – for those who can afford it.
Old coal mines could have a role to play in heating homes, without burning fossil fuels. Martha Henriques explores the buildings heated from old mine workings.
Kelp is fast and relatively easy to grow, and already a vital food in many parts of the world. Martha Henriques asks whether it could also power the aircraft of the future.