What did Jesus mean by these two things?

Matthew 24:22 And except those days should be shortened, there should no flesh be saved: but for the elect’s sake those days shall be shortened.

When Jesus said, "no flesh be saved", was he speaking about in the entire earth, or was he referring to only in Israel?

Was he referring to the following?

Zechariah 13:8 And it shall come to pass, that in all the land, saith the LORD, two parts therein shall be cut off and die; but the third shall be left therein.

  9 And I will bring the third part through the fire, and will refine them as silver is refined, and will try them as gold is tried: they shall call on my name, and I will hear them: I will say, It is my people: and they shall say, The LORD is my God.

Was the, "days should be shortened", referring to the three and a half years, that had it been longer, then even the third part would have died?

Or was he referring to shortening the days to even less that three and a half years?