It is a fact that excessive herding of animals and exploitation of grasslands are responsible for the majority of dust storms.
This means that dust storms are largely a result of human actions; in other words, they are controllable.

事实上，沙尘暴形成的主要原因是过度放牧及滥垦草原
这表明沙尘暴大多是人的活动所导致， 也就是说，它们是可加以控制的。