Iabsolutely need now! is it possible for populations to be affected by weather? give examples

Yes of course!
In the most catastrophic case, it can kill hundreds of thousands through hurricanes and the things that come with hurricanes. 
Droughts can cause death by both dehydration and starvation if the rain is the only dependable source of arrogation 
Too much rain causes floods which can be fatal too

Yes, the best example is Antarctica and Sahara desert.
The land present is vast but population is very less or we can say no population

Self-reports would be the answer.