Business Green: Some of the world’s largest rivers, including the Ganges, the Niger and the Colorado, are drying up as a result of climate change with potentially catastrophic consequences for many of the world’s most populous regions and cities. That is the stark warning from a major new study undertaken by the US National Center for Atmospheric Research, which found that one third of the world’s mightiest rivers have seen significant changes in flow levels over the past 50 years, largely as a …