By Suzanne Goldenberg Some of the mightiest rivers on the planet, including the Ganga, the Niger, and the Yellow river in China, are drying up because of climate change, a study of global waterways has warned. The study by the National Centre for Atmospheric Research in Colorado found that global warming has had a far more damaging impact on rivers than had been realised and that, overwhelmingly, those rivers in highly populated areas were the most severely affected. That could threaten food and water supply to millions of people living in some of the world