Seafood is popular on many menus, but over-fishing is costing the oceans dearly. Aquaculture is one answer, with fish farmed for consumption in protected environments. In South Africa, the industry is in its infancy, but companies are farming fish that are green-listed on the Southern African Sustainable Seafood Initiative.
It looks like something from a sci-fi film, with its massive tower and thousands of wall-like solar mirrors set in an arid and deserted landscape. But Khi Solar One, Africa's first concentrated solar power project, is a very real example of the future of renewable energy.
Gas is flared at Robinson Deep, Johannesburg's biggest landfill, and at Marie Louise, another of its five sites. But generators will be installed this year at the former to turn the methane into power. When all its landfills are all online, it will produce enough power to supply 12 500 middle-income households.
Is the universe expanding? What is dark energy? What's the deal with gravity? And the biggest question of all; are we alone? The Square Kilometre Array, which will aim to answer these questions and more, is slowly taking shape in a remote corner of South Africa's starry-skied Karoo.