South Africa’s Karoo, a vast arid wilderness, may contain gas reserves that could solve the country’s energy problems — but only through an extraction process called fracking that has greens seeing red. The sprawling and ecologically sensitive region, home to rare species such as the mountain zebra and riverine rabbit, may hold vast deposits of natural gas in shale rock deep underground. Once unobtainable, such reserves can now be exploited with new techniques and could serve as a badly needed energy source for Africa’s largest economy, which is heavily reliant on coal.