The SCALE of the flood / pollution /problem > here it means the size ( in a large) way. The scale of pollution -related problems is beyond your belief . The scale of the flood is disastrous , to say the least . You do not know the scale of my problem . The army armed themselves in a massive scale over the years . A scale of > here it means something this is having a size in relation to the original something . This is a small scale model of the palace . . I want you to built a bigger scale of that house for me .

You might want to include the context of where you heard "the scale of" with the question. The most general meaning, is about "estimating of the size of something".