CNN: When a ‘Yellow Dragon’ roars, Beijing listens. These huge, sky-blackening dust storms sweep across Asia in March and April, bringing with them millions of tons of sand from inner Mongolia and depositing it in China and on across the Korean peninsula to Japan. During the past few years the storms have grown in ferocity and scale, and they are at the vanguard of an advancing Gobi desert that threatens more than 400 million people in the Chinese provinces of Xinjiang, Inner …